The latest in display tech — multitouch skin

Via KurzweilAI.net — Like almost all announcements of this type of product, I’ll  be much more interested when this is available on the open market with practical applications. Of course, it’s still pretty cool to contemplate.

Multitouch ‘Skin’ Transforms Surfaces Into Interactive Screens

Physorg.com, Feb. 2, 2010 A new large-format multi-touch technology launched today by DISPLAX will transform any non-conductive flat or curved surface, such as glass, plastic or wood, into a multitouch screen. DISPLAX Multitouch Technology uses a controller that works by processing multiple input signals it receives from a grid of nanowires embedded in the film attached to the enabled surface. Each time a finger is placed on the screen or a user blows on the surface, a small electrical disturbance is caused. The microprocessor controller analyzes this data and decodes the location of each input on that grid to track the finger and air-flow movements. Read Original Article>>

Growing graphene

It’s been a while since I’ve blogged about graphene so I was pleased to read this news at the physics arXiv blog on a method to produce the material at a substantially lower cost. The hype about graphene probably is a bit over-the-top, but it’s proving to be quite the miracle nanomaterial.

From the second link:

The world of materials science is aflutter with stories about graphene, a supermaterial that is capable of almost anything (if you believe the hype). This form of carbon chickenwire, they tell us, is stronger, faster and better than almost any other material you care to name.

But not cheaper. At least not yet. The big problem with graphene is making it. The only way to get it is to chip away at a bigger block of graphite and then hunt through the flakes looking for single layers of the stuff. That’s not a technique that’s going to revolutionise the electronics industry, regardless of how much cheap labour is available in China.

That’s why an announcement from Hirokazu Fukidome at Tohoku University in Japan and a few buddies is hugely important. These guys say they have found a way to grow graphene on a silicon substrate. To show off their technique they’ve combined it with conventional lithography to create a graphene-on-silicon field effect transistor–just the kind of device the electronics industry wants to build by the billion.

That’s a big deal for two reasons. First, being able to grow graphene from scratch is going to be a huge boost to the study of this stuff and its myriad amazing properties. Second, being able to grow it on silicon makes it compatible (in principle at least) with the vast silicon-based fabrication industry as it stands.

Optical computing breakthrough

Via KurzweilAI.net — It really is fun watching to see where the next big advancement in computing comes from. Optical computers, quantum computers, something we haven’t even heard of yet? One thing is certain, computers will continue to become more and more powerful for the foreseeable future.

Spasers set to sum: A new dawn for optical computing

New Scientist Tech, Jan. 25, 2010 The “spaser,” the latest by-product of a buzzing field known as nanoplasmonics, based on plasmons, may lead to building a super-fast computer that computes with light. Plasmons, which are ultra-high-frerquency electron waves on a metallic surface, overcome the speed limits of the wires that interconnect transistors in chips, allowing for converting electronic signals into photonic ones and back again with speed and efficiency. Read Original Article>>

“Hot electrons” and solar cells

The latest solar breakthrough news.

The release:

Elusive ‘hot’ electrons captured in ultra-thin solar cells

Shrinking cells snares charges in less than one-trillionth of a second

CHESTNUT HILL, MA (12/11/2009) – Boston College researchers have observed the “hot electron” effect in a solar cell for the first time and successfully harvested the elusive charges using ultra-thin solar cells, opening a potential avenue to improved solar power efficiency, the authors report in the current online edition of Applied Physics Letters.

When light is captured in solar cells, it generates free electrons in a range of energy states. But in order to snare these charges, the electrons must reach the bottom of the conduction band. The problem has been that these highly energized “hot” electrons lose much of their energy to heat along the way.

Hot electrons have been observed in other devices, such as semiconductors. But their high kinetic energy can cause these electrons, also known as “hot carriers,” to degrade a device. Researchers have long theorized about the benefits of harnessing hot electrons for solar power through so-called “3rd generation” devices.

By using ultrathin solar cells – a film fewer than 30 nanometers thick – the team developed a mechanism able to extract hot electrons in the moments before they cool – effectively opening a new “escape hatch” through which they typically don’t travel, said co-author Michael J. Naughton, the Evelyn J. and Robert A. Ferris Professor of Physics at Boston College.

The team’s success centered on minimizing the environment within which the electrons are able to escape, said Professor of Physics Krzysztof Kempa, lead author of the paper.

Kempa compared the challenge to trying to heat a swimming pool with a pot of boiling water. Drop the pot into the center of the pool and there would be no change in temperature at the edge because the heat would dissipate en route. But drop the pot into a sink filled with cold water and the heat would likely raise the temperature in the smaller area.

“We have shrunk the size of the solar cell by making it thin,” Kempa said. “In doing so, we are bringing these hot electrons closer to the surface, so they can be collected more readily. These electrons have to be captured in less than a picosecond, which is less than one trillionth of a second.”

The ultrathin cells demonstrated overall power conversion efficiency of approximately 3 percent using absorbers one fiftieth as thick as conventional cells. The team attributed the gains to the capture of hot electrons and an accompanying reduction in voltage-sapping heat. The researchers acknowledged the film’s efficiency is limited by the negligible light collection of ultra-thin junctions. However, combining the film with better light-trapping technology – such as nanowire structures – could significantly increase efficiency in an ultra-thin hot electron solar cell technology.

###

In addition to Naughton and Kempa, the research team included Professor of Physics Zhifeng Ren, Research Associate Professor and Laboratory Director Andrzej A. Herczynski, Research Scientist Yantao Gao, doctoral student Timothy Kirkpatrick, and Jakub Rybczynski of Solasta Corp., of Newton MA, which supported the research. Naughton, Kempa and Ren are principals in the clean energy firm as well.

Macro yarn from nano fibers

Step aside Kevlar, your replacement just clocked in.

This nanotech product looks to have immediate practical applications. Anyone who was a serious tennis player quite some ago ought to remember the Prince Boron racket. Outrageously priced at $500 in a time when cracking three figures was very, very expensive for tennis equipment. I wonder how much an updated version using this boron nitride nanofiber yarn would command?

From the first link, the release:

A yarn spun of boron-nitride nanotubes suspends a quarter.

NEWPORT NEWS, VA, Dec. 2 –Researchers have used lasers to create the first practical macroscopic yarns from boron nitride fibers, opening the door for an array of applications, from radiation-shielded spacecraft to stronger body armor, according to a just-published study.

Researchers at NASA’s Langley Research Center, the Department of Energy’s Thomas Jefferson National Accelerator Facility and the National Institute of Aerospace created a new technique to synthesize high-quality boron-nitride nanotubes (BNNTs). They are highly crystalline and have a small diameter. They also structurally contain few walls and are very long. Boron nitride is the white material found in clown make-up and face powder.

“Before, labs could make really good nanotubes that are are short or really crummy ones that are long. We’ve developed a technique that makes really good ones that are really long,” said Mike Smith, a staff scientist at NASA’s Langley Research Center.

The synthesis technique, called the pressurized vapor/condenser (PVC) method, was developed with Jefferson Lab’s Free-Electron Laser and later perfected using a commercial welding laser. In this technique, the laser beam strikes a target inside a chamber filled with nitrogen gas. The beam vaporizes the target, forming a plume of boron gas. A condenser, a cooled metal wire, is inserted into the boron plume. The condenser cools the boron vapor as it passes by, causing liquid boron droplets to form. These droplets combine with the nitrogen to self-assemble into BNNTs.

Researchers used the PVC method to produce the first high-quality BNNTs that are long enough to be spun into macroscopic yarn, in this case centimeters long. A cotton-like mass of nanotubes was finger-twisted into a yarn about one millimeter wide, indicating that the nanotubes themselves are about one millimeter long.

Fibrils of boron-nitride nanotubes are formed through the pressurized vapor/condenser method. The nanotube fibrils are produced when the FEL laser beam strikes a target of pressed boron powder. The number indicates laser power level in arbitrary units; about 1.5 kW in actuality. The target rotates to distribute the laser heat evenly.
(click image to view the video)

“They’re big and fluffy, textile-like,” said Kevin Jordan, a staff electrical engineer at Jefferson Lab. “This means that you can use commercial textile manufacturing and handling techniques to blend them into things like body armor and solar cells and other applications.”

Transmission electron microscope images show that the nanotubes are very narrow, averaging a few microns in diameter. TEM images also revealed that the BNNTs tended to be few-walled, most commonly with two-five walls, although single-wall nanotubes were also present. Each wall is a layer of material, and fewer-walled nanotubes are the most sought after.

The researchers say the next step is to test the properties of the new boron-nitride nanotubes to determine the best potential uses for the new material. They are also attempting to improve and scale up the production process.

“Theory says these nanotubes have energy applications, medical applications and, obviously, aerospace applications,” said Jordan.

Smith agreed, “Some of these things are going to be dead ends and some are going to be worth pursuing, but we won’t know until we get material in people’s hands.”

The research will be published in the December 16 issue of the journal Nanotechnology. The article is available for a short time online. It will also be presented at the 2009 Materials Research Society Fall Meeting on December 3.

The research was supported by the NASA Langley Creativity and Innovation Program, the NASA Subsonic Fixed Wing program, DOE’s Jefferson Lab and the Commonwealth of Virginia. The experiments were hosted at Jefferson Lab.

Jefferson Lab is managed and operated for the U.S. Department of Energy’s Office of Science by Jefferson Science Associates, LLC, a joint venture between Southeastern Universities Research Association, Inc. and CSC Applied Technologies Division, LLC.

Semiconducting nanowires are coming

With all the news about nanotechnology and wiring that’s been coming out over the last year or so, this release is no surprise.

The release:

November 26, 2009

Nanowires key to future transistors, electronics

WEST LAFAYETTE, Ind. -

Nanowire formation
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caption below

A new generation of ultrasmall transistors and more powerful computer chips using tiny structures called semiconducting nanowires are closer to reality after a key discovery by researchers at IBM, Purdue University and the University of California at Los Angeles.The researchers have learned how to create nanowires with layers of different materials that are sharply defined at the atomic level, which is a critical requirement for making efficient transistors out of the structures.

 

“Having sharply defined layers of materials enables you to improve and control the flow of electrons and to switch this flow on and off,” said Eric Stach, an associate professor of materials engineering at Purdue.

Electronic devices are often made of “heterostructures,” meaning they contain sharply defined layers of different semiconducting materials, such as silicon and germanium. Until now, however, researchers have been unable to produce nanowires with sharply defined silicon and germanium layers. Instead, this transition from one layer to the next has been too gradual for the devices to perform optimally as transistors.

The new findings point to a method for creating nanowire transistors.

The findings are detailed in a research paper appearing Friday (Nov. 27) in the journal Science. The paper was written by Purdue postdoctoral researcher Cheng-Yen Wen, Stach, IBM materials scientists Frances Ross, Jerry Tersoff and Mark Reuter at the Thomas J. Watson Research Center in Yorktown Heights, N.Y, and Suneel Kodambaka, an assistant professor at UCLA’s Department of Materials Science and Engineering.

Whereas conventional transistors are made on flat, horizontal pieces of silicon, the silicon nanowires are “grown” vertically. Because of this vertical structure, they have a smaller footprint, which could make it possible to fit more transistors on an integrated circuit, or chip, Stach said.

“But first we need to learn how to manufacture nanowires to exacting standards before industry can start using them to produce transistors,” he said.

Nanowires might enable engineers to solve a problem threatening to derail the electronics industry. New technologies will be needed for industry to maintain Moore’s law, an unofficial rule stating that the number of transistors on a computer chip doubles about every 18 months, resulting in rapid progress in computers and telecommunications. Doubling the number of devices that can fit on a computer chip translates into a similar increase in performance. However, it is becoming increasingly difficult to continue shrinking electronic devices made of conventional silicon-based semiconductors.

“In something like five to, at most, 10 years, silicon transistor dimensions will have been scaled to their limit,” Stach said.

Transistors made of nanowires represent one potential way to continue the tradition of Moore’s law.

The researchers used an instrument called a transmission electron microscope to observe the nanowire formation. Tiny particles of a gold-aluminum alloy were first heated and melted inside a vacuum chamber, and then silicon gas was introduced into the chamber. As the melted gold-aluminum bead absorbed the silicon, it became “supersaturated” with silicon, causing the silicon to precipitate and form wires. Each growing wire was topped with a liquid bead of gold-aluminum so that the structure resembled a mushroom.

Then, the researchers reduced the temperature inside the chamber enough to cause the gold-aluminum cap to solidify, allowing germanium to be deposited onto the silicon precisely and making it possible to create a heterostructure of silicon and germanium.

The cycle could be repeated, switching the gases from germanium to silicon as desired to make specific types of heterostructures, Stach said.

Having a heterostructure makes it possible to create a germanium “gate” in each transistor, which enables devices to switch on and off.

The work is based at IBM’s Thomas J. Watson Research Center and Purdue’s Birck Nanotechnology Center in the university’s Discovery Park and is funded by the National Science Foundation through the NSF’s Electronic and Photonic Materials Program in the Division of Materials Research.

PHOTO CAPTION:
Researchers are closer to using tiny devices called semiconducting nanowires to create a new generation of ultrasmall transistors and more powerful computer chips. The researchers have grown the nanowires with sharply defined layers of silicon and germanium, offering better transistor performance. As depicted in this illustration, tiny particles of a gold-aluminum alloy were alternately heated and cooled inside a vacuum chamber, and then silicon and germanium gases were alternately introduced. As the gold-aluminum bead absorbed the gases, it became “supersaturated” with silicon and germanium, causing them to precipitate and form wires. (Purdue University, Birck Nanotechnology Center/Seyet LLC)

Silicon nanowires

Carbon gets most of the nanotech ink, but here’s some news on silicon nanowires.

The release:

Understanding mechanical properties of silicon nanowires paves way for nanodevices

		IMAGE: These are silicon nanowires used in the in-situ scanning electron microscopy mechanical testing by Dr. Yong Zhu and his team. Click here for more information.

Silicon nanowires are attracting significant attention from the electronics industry due to the drive for ever-smaller electronic devices, from cell phones to computers. The operation of these future devices, and a wide array of additional applications, will depend on the mechanical properties of these nanowires. New research from North Carolina State University shows that silicon nanowires are far more resilient than their larger counterparts, a finding that could pave the way for smaller, sturdier nanoelectronics, nanosensors, light-emitting diodes and other applications.

It is no surprise that the mechanical properties of silicon nanowires are different from “bulk” – or regular size – silicon materials, because as the diameter of the wires decrease, there is an increasing surface-to-volume ratio. Unfortunately, experimental results reported in the literature on the properties of silicon nanowires have reported conflicting results. So the NC State researchers set out to quantify the elastic and fracture properties of the material.

“The mainstream semiconductor industry is built on silicon,” says Dr. Yong Zhu, assistant professor of mechanical engineering at NC State and lead researcher on this project. “These wires are the building blocks for future nanoelectronics.” For this study, researchers set out to determine how much abuse these silicon nanowires can take. How do they deform – meaning how much can you stretch or warp the material before it breaks? And how much force can they withstand before they fracture or crack? The researchers focused on nanowires made using the vapor-liquid-solid synthesis process, which is a common way of producing silicon nanowires.

		IMAGE: Dr. Yong Zhu and his research team stand front of a scanning electron microscope. From left to right, they are Feng Xu, Qingquan Qin and Yong Zhu. Click here for more information.

Zhu and his team measured the nanowire properties using in-situ tensile testing inside scanning electron microscopy. A nanomanipulator was used as the actuator and a micro cantilever used as the load sensor. “Our experimental method is direct but simple,” says Qingquan Qin, a Ph.D. student at NC State and co-author of the paper. “This method offers real-time observation of nanowire deformation and fracture, while simultaneously providing quantitative stress and strain data. The method is very efficient, so a large number of specimens can be tested within a reasonable period of time.”

As it turns out, silicon nanowires deform in a very different way from bulk silicon. “Bulk silicon is very brittle and has limited deformability, meaning that it cannot be stretched or warped very much without breaking.” says Feng Xu, a Ph.D. student at NC state and co-author of the paper, “But the silicon nanowires are more resilient, and can sustain much larger deformation. Other properties of silicon nanowires include increasing fracture strength and decreasing elastic modulus as the nanowire gets smaller and smaller.”

The fact that silicon nanowires have more deformability and strength is a big deal. “These properties are essential to the design and reliability of novel silicon nanodevices,” Zhu says. “The insights gained from this study not only advance fundamental understanding about size effects on mechanical properties of nanostructures, but also give designers more options in designing nanodevices ranging from nanosensors to nanoelectronics to nanostructured solar cells.”

###

The study, “Mechanical Properties of Vapor-Liquid-Solid Synthesized Silicon Nanowires,” was co-authored by Zhu, Xu, Qin, University of Michigan (UM) researcher Wei Lu and UM Ph.D. student Wayne Fung. The study is published in the Nov. 11 issue o fNano Letters, and was funded by grants from the National Science Foundation and NC State.

Carbon nanotubes are the wiring of the future

Previously I’ve blogged about carbon nanotubes replacing copper wiring, and here’s news of a new manufacturing technique that gets that idea closer to the mainstream. This shift in wiring is most likely a “when” instead of an “if.”

From the second link:

A new method for assembling carbon nanotubes has been used to create fibers hundreds of meters long. Individual carbon nanotubes are strong, lightweight, and electrically conductive, and could be valuable as, among other things, electrical transmission wires. But aligning masses of the nanotubes into well-ordered materials such as fibers has proven challenging at a scale suitable for manufacturing. By processing carbon nanotubes in a solution called a superacid, researchers at Rice University have made long fibers that might be used as lightweight, efficient wires for the electrical grid or as the basis of structural materials and conductive textiles.

Others have made carbon-nanotube fibers by pulling the tubes from solid hair-like arrays or by spinning them like wool as they emerge from a chemical reactor. The problem with starting from a solid, says Rice chemical engineering professor Matteo Pasquali, is that “the alignment is not spectacular, and these methods are difficult to scale up.” The better aligned and ordered the individual nanotubes in a larger structure, the better the collective structure’s electrical and mechanical properties. Using the Rice methods, well-aligned nanotube fibers can be made on a large scale, shot out from a nozzle similar to a showerhead.

The late Nobel laureate Richard Smalley started the Rice project in 2001. Smalley knew solution-processing would be a good way to assemble nanotube fibers and films because of nanotubes’ shape. Carbon nanotubes are much longer than they are wide, so when they’re in a flowing solution, they line up like logs floating down a river. But carbon nanotubes aren’t soluble in conventional solvents. The Rice group laid the foundations for liquid processing of the nanotubes five years ago, when they discovered that sulfuric acid brings the nanotubes into solution by coating their surfaces with positively charged ions.

Nanotube fiber: This fiber, which is about 40 micrometers in diameter, is made up of carbon nanotubes.
Credit: Rice University

Improving dye-sensitized solar cells

Efficiencies are going up and costs and holding steady or falling. All this bodes well for the future of solar power.

From the link:

Dye-sensitized solar cells are flexible and cheap to make, but they tend to be inefficient at converting light into electricity. One way to boost the performance of any solar cell is to increase the surface area available to incoming light. So a group of researchers at Georgia Tech has made dye-sensitized solar cells with a much higher effective surface area by wrapping the cells around optical fibers. These fiber solar cells are six times more efficient than a zinc oxide solar cell with the same surface area, and if they can be built using cheap polymer fibers, they shouldn’t be significantly more expensive to make.

The advantage of a fiber-optic solar-cell system over a planar one is that light bounces around inside an optical fiber as it travels along its length, providing more opportunities to interact with the solar cell on its inner surface and producing more current. “For a given real estate, the total area of the cell is higher, and increased surface area means improved light harvesting and more energy,” says Max Shtein, an assistant professor of materials science and engineering at the University of Michigan who was not involved with the research.

Solar on fiber: An optical fiber (left) is covered in dye-coated zinc-oxide nanowires (closeup, right). Both images were made using a scanning electron microscope.
Credit: Angewandte Chemie

A beautiful nanotech image

I regularly have blog posts that feature nanotech images, and sometimes I just run a nanotechnology image because it is so beautiful. This is one of those times –

2004: Quantum dot nanocrystals deposited on a silicon substrate (200x), Polarized reflected light. / Seth A. Coe-Sullivan, Massachusetts Institute of Technology. Courtesy of Nikon Small World. The 2004 runners up.

2009 Feynman Prize winners announced by Foresight Institute

News from the nanotech think tank:

PALO ALTO, Calif., Oct 06, 2009 (BUSINESS WIRE) — The Foresight Institute, a nanotechnology education and public policy think tank based in Palo Alto, has announced the winners of the prestigious 2009 Foresight Institute Feynman Prizes in Nanotechnology.

Established in 1993 in honor of Nobel Prize winner Richard Feynman, two $5,000 prizes are awarded in two categories, theory and experiment, to recognize researchers whose recent work has most advanced the field toward the achievement of Feynman’s vision for nanotechnology: molecular manufacturing, the construction of atomically-precise products through the use of molecular machine systems.

The winner of the 2009 Feynman Prize for Experimental work is the team of Yoshiaki Sugimoto, Masayuki Abe (Osaka University), and Oscar Custance (National Institute for Materials Science, Japan), in recognition of their pioneering experimental demonstrations of mechanosynthesis, specifically the use of atomic resolution dynamic force microscopy — also known as non-contact atomic force microscopy (NC-AFM) — for vertical and lateral manipulation of single atoms on semiconductor surfaces. Their work, published in Nature, Science, and other prestigious scientific journals, has demonstrated a level of control over the ability to identify and position atoms on surfaces at room temperature which opens up new possibilities for the manufacture of atomically precise structures.

The winner of the 2009 Feynman Prize for Theory is Robert A. Freitas Jr. (IMM), in recognition of his pioneering theoretical work in mechanosynthesis in which he proposed specific molecular tools and analyzed them using ab initio quantum chemistry to validate their ability to build complex molecular structures. This Prize also recognizes his previous work in systems design of molecular machines, including replicating molecular manufacturing systems which should eventually be able to make large atomically precise products economically and the design of medical nanodevices which should eventually revolutionize medicine.

“What once seemed like a distant vision when it was first outlined by Feynman in 1959 — a new manufacturing technology able to arrange the very atoms that are the fundamental building blocks of matter — has come a step closer to reality,” said J. Storrs Hall, President of Foresight Institute. “This is no small thing, for all manufactured products are made from atoms — and if we can better control how those atoms are arranged we can make fundamentally better products.

“Products that are remarkably light, strong, smart, green, and cheap. Molecular manufacturing will dwarf the Industrial Revolution.”

The Feynman Prizes will be awarded in person in January near the Palo Alto headquarters of Foresight Institute.

About Foresight Institute http://www.foresight.org/

Foresight Institute is a leading think tank and public interest organization focused on nanotechnology. Foresight dedicates itself to providing education, policy development, and networking to ensure the beneficial implementation of molecular manufacturing.

Getting carbon nanotubes under control

An important aspect of creating nanotubes is controlling their atomic-level structure. Looks like these researchers have found a solution to the issue.

From the link:

Single‐walled carbon nanotubes, made of a cheap and abundant material, have so much potential because their function changes when their atomic‐level structure, referred to as chirality, changes.

But for all their promise, building tubes with the right structure has proven a challenge.

A pair of Case Western Reserve University researchers mixed metals commonly used to grow nanotubes 
and found that the composition of the catalyst can control the chirality.

In a letter to be published Sept. 20 in the online edition of Nature Materials, R. Mohan Sankaran, an assistant professor of chemical engineering at the Case School of Engineering, and Wei‐Hung Chiang, who received his doctorate degree in chemical engineering in May, describe their findings.

“We have established a link between the structure of a catalyst and the chirality of carbon nanotubes,” 
Sankaran said. “Change the catalyst structure by varying its composition, and you can begin to control the chirality of the nanotubes and their electrical and optical properties.”

The chirality of a single‐walled carbon nanotube describes how a lattice of carbon atoms is rolled into a tube. The rolling can occur at different angles, producing different structures that exhibit very different properties.

Nanotubes are normally grown in bulk mixtures. When using a nickel catalyst, typically one‐third of those grown are metallic and could be used like metal wires to conduct electricity. About two‐thirds are semiconducting nanotubes, which could be used as transistors, Chiang explained. But, separating them according to properties, “is costly and can damage the nanotubes.”

The future of technology looks pretty bright

I’ve blogged on all three of the technologies — OLEDs and nanowires pretty extensively — but this is a very nice thumbnail sketch of what’s at the edge of the real-world horizon, if not already here.

From the last link:

Have a look at just three technologies that have the ability to completely revolutionize IT from the ground up: memristors, nanowires and OLEDS.

Memristors are transistor-like devices made out of titanium dioxide that can remember voltage state information. They hold the potential for completely revolutionizing storage and processing technologies because they erase the distinction between processing and storage (you can do both/and on the same chip). More prosaically, they make it possible to create storage devices that require no power. How will that affect your data center?

Then there are nanowires: tiny wires no more than a single nanometer in width that can be conductors, insulators or semiconductors (albeit with weird quantum properties). These can form the basis for embedded intelligent networks — sensor and control networks that are actually built into the materials and devices they control. (Take that, smart grids!)

Finally, there are organic LEDs, which have the interesting property that they can be printed onto things such as wallpaper at relatively low cost. Sony has developed OLED monitors, and GE is looking into OLED wallpaper. So in a couple of years, your new office (or home office) may come equipped with wallpaper that, at the touch of a button, can turn into a floor-to-ceiling high-resolution display. (Think of the bandwidth requirements).

Each of these technologies holds the possibility of completely reshaping IT within the next few years. And the conjunction of all three could make the conjunction of the transistor and fiber optics look like a warm-up act.

Carbon nanotubes and electronics

Via KurzweilAI — This post is a two-fer on nanotech and carbon nanotubes.

From the “two” link:

Using Nanotubes in Computer Chips

PhysOrg.com, Sep. 10, 2009 A simple enough manufacturing process developed by MITresearchers could enable carbon nanotubes to replace the vertical wires in chips, permitting denser packing ofcircuits. Read Original Article>>

And from the “fer” link:

Capsules for Self-Healing Circuits

Technology Review, Sept. 11, 2009 Nanotube-filled capsules could restore conductivity to damaged electronics, University of Illinois at Urbana-Champaign researchers have found. Read Original Article>>

Graphite, data storage and semiconductors

Interesting release from Rice involving graphite and nanotechnology, but not the usual carbon nanotubes, graphene or graphane.

The release:

Graphitic memory techniques advance at Rice

Researchers simplify fabrication of nano storage, chip-design tools

Advances by the Rice University lab of James Tour have brought graphite’s potential as a mass data storage medium a step closer to reality and created the potential for reprogrammable gate arrays that could bring about a revolution in integrated circuit logic design.

In a paper published in the online journal ACS Nano, Tour and postdoctoral associate Alexander Sinitskii show how they’ve used industry-standard lithographic techniques to deposit 10-nanometer stripes of amorphous graphite, the carbon-based, semiconducting material commonly found in pencils, onto silicon. This facilitates the creation of potentially very dense, very stable nonvolatile memory for all kinds of digital devices.

With backing from a major manufacturer of memory chips, Tour and his team have pushed the technology forward in several ways since a paper that appeared last November first described two-terminal graphitic memory. While noting advances in other molecular computing techniques that involve nanotubes or quantum dots, he said none of those have yet proved practical in terms of fabrication.

Not so with this simple-to-deposit graphite. “We’re using chemical vapor deposition and lithography — techniques the industry understands,” said Tour, Rice’s Chao Professor of Chemistry and a professor of mechanical engineering and materials science and of computer science. “That makes this a good alternative to our previous carbon-coated nanocable devices, which perform well but are very difficult to manufacture.”

Graphite makes a good, reliable memory “bit” for reasons that aren’t yet fully understood. The lab found that running a current through a 10-atom-thick layer of graphite creates a complete break in the circuit — literally, a gap in the strip a couple of nanometers wide. Another jolt repairs the break. The process appears to be indefinitely repeatable, which provides addressable ones and zeroes, just like today’s flash memory devices but at a much denser scale.

Graphite’s other advantages were detailed in Tour’s earlier work: the ability to operate with as little as three volts, an astoundingly high on/off ratio (the amount of juice a circuit holds when it’s on, as opposed to off) and the need for only two terminals instead of three, which eliminates a lot of circuitry. It’s also impervious to a wide temperature range and radiation; this makes it suitable for deployment in space and for military uses where exposure to temperature extremes and radiation is a concern.

Tour’s graphite-forming technique is well-suited for other applications in the semiconductor industry. One result of the previous paper is a partnership between the Tour group and NuPGA (for “new programmable gate arrays”), a California company formed around the research to create a new breed of reprogrammable gate arrays that could make the design of all kinds of computer chips easier and cheaper.

The Tour lab and NuPGA, led by industry veteran Zvi Or-Bach (founder of eASIC and Chip Express), have applied for a patent based on vertical arrays of graphite embedded in “vias,” the holes in integrated circuits connecting the different layers of circuitry. When current is applied to a graphite-filled via, the graphite alternately splits and repairs itself (a process also described in the latest paper), just like it does in strip form. Essentially, it becomes an “antifuse,” the basic element of one type of field programmable gate array (FPGA), best described as a blank computer chip that uses software to rewire the hardware.

Currently, antifuse FPGAs can be programmed once. But this graphite approach could allow for the creation of FPGAs that can be reprogrammed at will. Or-Bach said graphite-based FPGAs would start out as blanks, with the graphite elements split. Programmers could “heal” the antifuses at will by applying a voltage, and split them with an even higher voltage.

Such a device would be mighty handy to computer-chip designers, who now spend many millions to create the photolithography mask sets used in chip fabrication. If the design fails, it’s back to square one.

“As a result of that, people are only hesitantly investing in new chip designs,” said Tour. “They stick with the old chip designs and make modifications. FPGAs are chips that have no specific ability, but you use software to program them by interconnecting the circuitry in different ways.”  That way, he said, fabricators don’t need expensive mask sets to try new designs.

“The No. 1 problem in the industry, and one that gives an opportunity for a company like ours, is that the cost of masks keeps moving up as people push semiconductors into future generators,” said Or-Bach. “Over the last 10 years, the cost of a mask set has multiplied almost 10 times.

“If we can really make something that will be an order of magnitude better, the markets will be happy to make use of it. That’s our challenge, and I believe the technology makes it possible for us to do that.”

The ACS Nano paper appears here: http://pubs.acs.org/doi/pdf/10.1021/nn9006225

Read more about Tour’s research of graphitic memory here: 
http://www.media.rice.edu/media/NewsBot.asp?MODE=VIEW&ID=11817

To download images, go here: http://www.rice.edu/nationalmedia/images/graphitestripes.jpg
http://www.rice.edu/nationalmedia/images/graphitestripes2.jpg
http://www.rice.edu/nationalmedia/images/vias.jpg

Nanotech in the marketplace

I somehow let this release from last week’s inbox get past me. Pretty interesting information on real-world market application of nanotechnology.

The release:

Nanotech-enabled Consumer Products Top the 1,000 Mark

Public Inventory Continues to Grow

WASHINGTON, Aug. 25 /PRNewswire-USNewswire/ — Nanotech consumer products have now crossed the millennial threshold.

Over 1,000 nanotechnology-enabled products have been made available to consumers around the world, according to the Project on Emerging Nanotechnologies (PEN). The most recent update to the group’s three-and-a-half-year-old inventory reflects the increasing use of the tiny particles in everything from conventional products like non-stick cookware and lighter, stronger tennis racquets, to more unique items such as wearable sensors that monitor posture.

“The use of nanotechnology in consumer products continues to grow rapidly,” says PEN Director David Rejeski. “When we launched the inventory in March 2006 we only had 212 products. If the introduction of new products continues at the present rate, the number of products listed in the inventory will reach close to 1,600 within the next two years. This will provide significant oversight challenges for agencies like the Food and Drug Administration and Consumer Product Safety Commission, which often lack any mechanisms to identify nanotech products before they enter the marketplace.”

Health and fitness items continue to dominate the PEN inventory, representing 60 percent of products listed. More products are based on nanoscale silver — used for its antimicrobial properties — than any other nanomaterial; 259 products (26 percent of the inventory) use silver nanoparticles. The updated inventory represents products from over 24 countries, including the U.S., China, Canada, and Germany. This update also identifies products that were previously available, but for which there is no current information.

The release of the updated inventory coincides with the first public hearing on nanotechnology being held by the Consumer Product Safety Commission (CPSC).  The CPSC, with a staff of fewer than 400 employees, oversees the safety of 15,000 types of consumer products.

Andrew Maynard, chief science advisor for PEN, noted that “the CPSC deserves credit for focusing on nanotechnologies. The resources available to the agency to address health and safety issues are negligible compared to the over $1.5 billion federal investment in nanotechnology research and development.”

The inventory is available at http://www.nanotechproject.org/inventories/consumer/

The PEN consumer products inventory includes products that have been identified by their manufacturer or a credible source as being nanotechnology-based.  This update identifies products that were previously sold, but which may no longer be available.  It remains the most comprehensive and widely used source of information on nanotechnology-enabled consumer products in the world.

Nanotechnology is the ability to measure, see, manipulate and manufacture things usually between 1 and 100 nanometers . A nanometer is one billionth of a meter. A human hair is roughly 100,000 nanometers wide. The limit of the human eye’s capacity to see without a microscope is about 10,000 nanometers. In 2007 the global market for goods incorporating nanotechnology totaled $147 billion. Lux research projects that figure will grow to $3.1 trillion by 2015.

The Project on Emerging Nanotechnologies was launched in 2005 by the Wilson Center and The Pew Charitable Trusts. It is a partnership dedicated to helping business, governments, and the public anticipate and manage the possible health and environmental implications of nanotechnology. To learn more, visit www.nanotechproject.org.

Source: The Project on Emerging Nanotechnologies

Web Site:  http://www.nanotechproject.org/

American Society for Nanomedicine holding first conference in late October

Very hot from the inbox — news on the first conference from the new organiztion, the American Society for Nanomedicine:

Newly Formed American Society for Nanomedicine (ASNM) to Hold First Conference (www.amsocnanomed.org)

ASHBURN, Va., Sept. 4 /PRNewswire-USNewswire/ — Nanomedicine – the science and technology of diagnosing, treating and preventing disease to improve human health using nanotechnology – has the potential to revolutionize healthcare.  Current and future products range from miniaturized “smart pills” that precision-target certain cancers to nanosensors that are capable of navigating through the body for early detection of disorders.  These approaches have the ability to reduce toxicity for the patient, thereby improving efficacy and patient compliance.  The newly formed American Society for Nanomedicine (ASNM) is holding its inaugural conference on October 22-25, 2009 in the Washington D.C. area, where some of the biggest stakeholders in this emerging technology operate and practice.

This major interdisciplinary international conference is designed for physicians, scientists, policy-makers, engineers, lawyers and educators from government, academia and industry.  The conference venue is the Bolger Center in Potomac, Maryland, USA (http://www.dolce-bolger-center-hotel.com/).

This four-day conference will highlight numerous cutting-edge presentations broken up into various sessions focusing on innovations in nanomedicine and applications of nanotechnology to the pharmaceutical, device and biotechnology industries.  It will feature more than forty speakers, who are among the top researchers and leaders in various facets of nanomedicine throughout the world. The areas of emphasis are clinical applications of nanotechnology enabling successful vaccine development, effective cancer therapy and novel drug delivery approaches.  In addition, issues such as ethics, safety and toxicity, patent law, intellectual property and commercialization will be addressed.  Poster sessions, an award ceremony and numerous networking opportunities are included.

About American Society for Nanomedicine

American Society for Nanomedicine (ASNM) is a professional non-profit, medical society headquartered in Ashburn, Virginia, USA.  It promotes worldwide seminal research activities in nanomedicine and explores the applications of nanotechnology in the pharmaceutical, device and biotechnology industries.  Members also discuss issues such as ethics, toxicity, patents and commercialization.  They are drawn from diverse and overlapping fields such as biotechnology, engineering, medicine, policy and law. Members enjoy numerous benefits, including reduced rates to attend ASNM conferences and discounted rates to ASNM-affiliated journals.

Conference Information/Registration: www.amsocnanomed.org

Source: American Society for Nanomedicine

Web Site:  http://www.amsocnanomed.org/

NanoPen to improve nanotech manufacturing

Nanotech news from the American Chemical Society:

‘NanoPen’ may write new chapter in nanotechnology manufacturing

		IMAGE: These highly-magnified images are composed of tiny nanoparticles produced by a “NanoPen. “ Click here for more information.

Researchers in California are reporting development of a so-called “NanoPen” that could provide a quick, convenient way of laying down patterns of nanoparticles — from wires to circuits — for making futuristic electronic devices, medical diagnostic tests, and other much-anticipated nanotech applications. A report on the device, which helps solve a long-standing challenge in nanotechnology, appeared in ACS’ Nano Letters, a monthly journal.

In the new study, Ming Wu and colleagues point out that researchers have already developed several different techniques for producing patterns of nanoparticles, which are barely 1/50,000th the width of a human hair. But current techniques tend to be too complex and slow. They require bulky instrumentation and take minutes or even hours to complete. These techniques also require the use of very high temperatures to apply the nanostructures to their target surfaces. Such limitations prevent widespread application of such techniques, the researchers say.

The scientists say their NanoPen solves these problems. In lab studies, the researchers used it to deposit various nanoparticles into specific patterns in the presence of relatively low light and temperature intensities. The process, which requires the use of special “photoconductive” surfaces, takes only seconds to complete, they note. Manufacturers can adjust the size and density of the patterns by adjusting the voltage, light intensity, and exposure time applied during the process, the researchers say.

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ARTICLE #4 FOR IMMEDIATE RELEASE
“NanoPen: Dynamic, Low-Power, and Light-Actuated Patterning of Nanoparticles”

DOWNLOAD FULL TEXT ARTICLE: http://pubs.acs.org/stoken/presspac/presspac/full/10.1021/nl901239a

Nanotech across the United States

A release from this morning:

Putting Nanotechnology on the Map

New data show nanotechnology-related activities in every U.S. state

WASHINGTON, Aug. 18 /PRNewswire-USNewswire/ — Every state can now lay claim to the nanotechnology revolution.

Data released today by the Project on Emerging Nanotechnologies (PEN) highlights more than 1,200 companies, universities, government laboratories, and other organizations across all 50 U.S. states and in the District of Columbia that are involved in nanotechnology research, development, and commercialization. This number is up 50 percent from the 800 organizations identified just two years ago.

While many of the original “Nano Metro” clusters — areas with the nation’s highest concentration of nanotechnology companies, universities, research laboratories, and organizations — have maintained their prominence in the field, areas such as Boston have moved up in the rankings, while others, such as Raleigh, N.C., have broken into the top-ranked locations for the first time.

This information is part of PEN’s interactive map displaying the growing “Nano Metro” landscape, powered by Google Maps(R), and available online at www.nanotechproject.org/121. The map’s accompanying analysis ranks cities and states by numbers of companies, academic and government research centers, and organizations and technology focus by sector.

  Nanotechnology Map Highlights:

  –  The top 4 states overall (each with over 75 entries) are California,
      Massachusetts, New York, and Texas. These states have retained their
      lead since the first analysis was released in 2007. Ohio has moved up
      four spots as the state with the sixth most entries.  North Carolina
      has broken into the top 10 states for the first time.
  –  All 50 states and the District of Columbia have at least one company,
      university, government laboratory, or organization working in the
      field of nanotechnology.
  –  The top 6 Nano Metros (each with 30 or more entries) are: Boston; San
      Francisco; San Jose, Calif.; Raleigh; Middlesex-Essex, Mass.; and
      Oakland, Calif. Boston and San Francisco have taken the lead from San
      Jose. Raleigh has moved into the top 5 Nano Metros (displacing
      Oakland).
  –  The top 3 sectors for companies working in nanotechnology (each with
      over 200 entries) are: materials; tools and instruments; and medicine
      and health.

  –  The number of universities and government laboratories working in
      nanotechnology is still substantial, as it was in 2007, with 182
      identified.

“The rapid growth in nanotechnology activity across the United States illustrates the impact of continued and significant investments in nanoscience and nanoengineering by the federal government and private sector,” said PEN Director David Rejeski.  “There is now not a single state without organizations involved in this cutting-edge field.”

The global market for goods based on nanotechnology is predicted to grow from $147 billion in 2007 to $3.1 trillion in 2015, according to the research and advisory firm Lux Research. “Given this expected continuation in growth, the ‘Nano Metro’ map remains a work in progress and will be further updated as more data becomes available,” according to Rejeski.

About Nanotechnology

Nanotechnology is the ability to measure, see, manipulate and manufacture things usually between 1 and 100 nanometers. A nanometer is one billionth of a meter; a human hair is roughly 100,000 nanometers wide.

The Project on Emerging Nanotechnologies was launched in 2005 by the Wilson Center and The Pew Charitable Trusts. It is a partnership dedicated to helping business, governments, and the public anticipate and manage the possible health and environmental implications of nanotechnology. To learn more, visit www.nanotechproject.org.

Source: The Project on Emerging Nanotechnologies
   
Web Site:  http://www.nanotechproject.org/

Lockheed Martin announces job cuts

A release from around an hour ago:

Lockheed Martin Space Systems Company Announces Workforce Reductions

DENVER, Aug. 17 /PRNewswire/ — Lockheed Martin Space Systems Company, a major business area of the Lockheed Martin Corporation (NYSE:LMT), today announced employment reductions aimed at improving its competitive posture.

Space Systems will implement a broad-based workforce reduction of approximately 800 employees by year-end. The reductions represent about 4.5 percent of the overall workforce and will impact all levels and disciplines, including technical, managerial, and administrative positions primarily at the Denver, Colo., and Sunnyvale, Calif. facilities. The company also will offer a voluntary layoff plan designed to minimize the number of layoffs necessary.

The reductions announced today are separate from the ongoing downsizing underway at the company’s Michoud Operations as a result of the planned fly-out of the Space Shuttle program in 2010.

Joanne Maguire, executive vice president, Lockheed Martin Space Systems Company, said, “The action we are taking, though difficult, is necessary to adapt to our current projected business base and to maintain an appropriate workforce to meet our customers’ needs.”

Maguire reaffirmed the company’s dedication to mission success: “Space Systems is a sound enterprise with technical breadth and unmatched capabilities. We will remain relentlessly focused on operational excellence and mission success as we position ourselves for the future.”

The company will provide career transition support to those impacted by these workforce reductions.

Lockheed Martin Space Systems Company designs and develops, tests, manufactures and operates a full spectrum of advanced-technology systems for national security and military, civil government and commercial customers. Chief products include human space flight systems; a full range of remote sensing, navigation, meteorological and communications satellites and instruments; space observatories and interplanetary spacecraft; laser radar; ballistic missiles; missile defense systems; and nanotechnology research and development.

Headquartered in Bethesda, Md., Lockheed Martin is a global security company that employs about 146,000 people worldwide and is principally engaged in the research, design, development, manufacture, integration and sustainment of advanced technology systems, products and services. The corporation reported 2008 sales of $42.7 billion.

Source: Lockheed Martin
   
Web Site:  http://www.lockheedmartin.com/

DNA scaffolding and circuit boards

A release red hot from the inbox:

IBM Scientists Use DNA Scaffolding To Build Tiny Circuit Boards

Nanotechnology advancement could lead to smaller, faster, more energy efficient computer chips

SAN JOSE, Calif., Aug. 17 /PRNewswire-FirstCall/ — Today, scientists at IBM Research (NYSE:IBM) and the California Institute of Technology announced a scientific advancement that could be a major breakthrough in enabling the semiconductor industry to pack more power and speed into tiny computer chips, while making them more energy efficient and less expensive to manufacture.

  (Photo:  http://www.newscom.com/cgi-bin/prnh/20090817/NY62155-a )
  (Photo:  http://www.newscom.com/cgi-bin/prnh/20090817/NY62155-b )
  (Logo:  http://www.newscom.com/cgi-bin/prnh/20090416/IBMLOGO )

IBM Researchers and collaborator Paul W.K. Rothemund, of the California Institute of Technology, have made an advancement in combining lithographic patterning with self assembly – a method to arrange DNA origami structures on surfaces compatible with today’s semiconductor manufacturing equipment.

Today, the semiconductor industry is faced with the challenges of developing lithographic technology for feature sizes smaller than 22 nm and exploring new classes of transistors that employ carbon nanotubes or silicon nanowires. IBM’s approach of using DNA molecules as scaffolding — where millions of carbon nanotubes could be deposited and self-assembled into precise patterns by sticking to the DNA molecules – may provide a way to reach sub-22 nm lithography.

The utility of this approach lies in the fact that the positioned DNA nanostructures can serve as scaffolds, or miniature circuit boards, for the precise assembly of components – such as carbon nanotubes, nanowires and nanoparticles – at dimensions significantly smaller than possible with conventional semiconductor fabrication techniques. This opens up the possibility of creating functional devices that can be integrated into larger structures, as well as enabling studies of arrays of nanostructures with known coordinates.

“The cost involved in shrinking features to improve performance is a limiting factor in keeping pace with Moore’s Law and a concern across the semiconductor industry,” said Spike Narayan, manager, Science & Technology, IBM Research – Almaden. “The combination of this directed self-assembly with today’s fabrication technology eventually could lead to substantial savings in the most expensive and challenging part of the chip-making process.”

The techniques for preparing DNA origami, developed at Caltech, cause single DNA molecules to self assemble in solution via a reaction between a long single strand of viral DNA and a mixture of different short synthetic oligonucleotide strands. These short segments act as staples – effectively folding the viral DNA into the desired 2D shape through complementary base pair binding. The short staples can be modified to provide attachment sites for nanoscale components at resolutions (separation between sites) as small as 6 nanometers (nm). In this way, DNA nanostructures such as squares, triangles and stars can be prepared with dimensions of 100 – 150 nm on an edge and a thickness of the width of the DNA double helix.

IBM uses traditional semiconductor techniques, the same used to make the chips found in today’s computers, to etch out patterns, creating the lithographic templates for this new approach. Either electron beam or optical lithography are used to create arrays of binding sites of the proper size and shape to match those of individual origami structures. The template materials are chosen to have high selectivity so that origami binds only to the patterns of “sticky patches” and nowhere else.

The paper on this work, “Placement and orientation of DNA nanostructures on lithographically patterned surfaces,” by scientists at IBM Research and the California Institute of Technology will be published in the September issue of Nature Nanotechnology and is currently available at: http://www.nature.com/nnano/journal/vaop/ncurrent/abs/nnano.2009.220.html.

For more information about IBM Research, please visit http://www.research.ibm.com/.

To view and download DNA scaffolding images, in high or low resolution, please go to: http://www.thenewsmarket.com/ibm.

Photo:  http://www.newscom.com/cgi-bin/prnh/20090416/IBMLOGO
http://www.newscom.com/cgi-bin/prnh/20090817/NY62155-b
http://www.newscom.com/cgi-bin/prnh/20090817/NY62155-a
PRN Photo Desk, photodesk@prnewswire.com
Source: IBM
  

Web Site:  http://www.research.ibm.com/

Practical solar power

This release is really more of an article on making solar power practical than it is an announcement of news. It’s an interesting read on solar.

The release:

Bringing solar power to the masses

On a 104-degree Friday in July when sunlight bathed The University of Arizona campus, doctoral student Dio Placencia sat before a noisy vacuum chamber in the Chemical Sciences Building trying to advance the renewable energy revolution.

As a member of UA professor Neal R. Armstrong’s research group, Placencia conducts research aimed at creating a thin, flexible organic solar cell that could power a tent or keep a car charged between trips to work and back home again.

He’s passionate about renewable energy and says it’s a waste that so little solar has been incorporated into society. “I have a little flat panel that I walk around with,” Placencia said. “I usually put that on my backpack, and I charge my cell phone when I’m walking to school.”

The sun is clean and free. “Here it is,” he said. “Why not use it?”

Across the University, professors, researchers, students and others involved in policy planning and economic analysis are working to make that question moot. In a region noted for abundant sunlight, they are chipping away at problems like how to employ solar at the utility-generating plant level, how to harness it to charge the newly indispensable products of the day – cell phones, MP3 players, laptops – what to do at night and when clouds halt the energy giveaway from the sky.

The research proceeds in labs amid state-of-the-art equipment funded by multimillion-dollar federal grants. It’s the product of students’ hunches and long careers spent unlocking the mysteries of science. Along the way, students are being immersed in a nascent industry that many hope will be the economic engine of the next decade.

“Looking at renewable energy is a perfect place to emphasize that we don’t know where the next breakthrough is going to be,” said Leslie P. Tolbert, UA vice president for research, graduate studies and economic development. “Somewhere in a lab someplace, there’s somebody figuring out a whole new way to capture sunlight. In fact, there are many people doing that. And even they are depending on knowing that there is, behind them, a cadre of basic science researchers producing new information that will feed their thoughts.”

Armstrong, a professor of chemistry and optical sciences at the UA, occasionally teaches freshman chemistry. He decided one day near the end of the semester to try to make the material even more relevant. “I said to myself, well, lithium ion batteries in my cell phone, in my iPod,” – his daughter had given him one – “I wonder how much coal we burn to charge those guys up at the end of the day. Because that’s one of the big drivers for portable power, to get all this stuff off the grid.” After making some very conservative calculations, he arrived at an answer, which he shared with the class: “You burn about a quarter of a pound of coal per charge of your lithium ion battery, and you generate about half a pound of CO2 per charge, per battery, per day …. The room got really quiet.”

The next time, he intends to calculate how much coal is burned per Twitter tweet.

“It really is chilling,” Armstrong said. “You start doing the math and thinking about the number of consumer electronic devices that you and I have added to our lives in the last decade that I charge up typically once every night – my laptop computer and my cell phone. Then you start thinking about, ‘What if I do buy an electric car, and I come home at night and plug that sucker in,’ and you do the same thing. We’ll shut this grid down in no time.”

In April, the U.S. Department of Energy announced it was funding Armstrong’s Center for Interface Science as one of 46 Energy Frontier Research Centers. The mission of these centers, which will receive $2 million to $5 million a year for five years, is “to address current fundamental scientific roadblocks to clean energy and energy security,” according to the DOE.

Ever since Armstrong was a graduate student during the first Arab oil embargo in 1973, he’s experienced a succession of government distress calls over energy. One such emergency led him to discover the work of Heinz Gerischer and Frank Willig in Germany. They had figured out how to adsorb dye molecules to the surface of oxides and split water with light from the sun. “I thought, ‘That’s it. That’s what I’m going to do my career on.’”

He moved to the UA in 1978, attracted by a program in photo-thermal solar energy conversion. In the 1980s, with gas cheap and plentiful again, solar went back on the back burner.

The next call came about four years ago. “DOE was beginning to sense that the tides were about to shift again, big-time,” Armstrong said. “And they were really concerned that they didn’t know what to do – how to present this to Congress in a way that would lead to new funding and which would have a rationale associated with it so that by the middle of this century we had someplace to go.”

Armstrong realized it was time to come back to the problem that he wanted to work on 30 years before. “This time, we were really well-equipped,” he said. “We’ve learned how to image molecules at the molecular level, we’ve learned how to measure energies of incredibly thin films, we’ve learned how to make devices, we’ve collaborated with physicists and material sciences and that sort of thing, we’ve done a lot of interesting other stuff and I suddenly realized I could bring it all back together here.”

In his office, he displays a sample of his work: a 1-inch square of glass on which is deposited a thin film of indium tin oxide, a conducting transparent oxide commonly found in display technologies like computer screens. On top of that is a thin film of organic dyes. The last layer is an aluminum electrode.

“You’d have a roll of plastic with these cells laid out on it,” he explained. “The idea is for you to go to Target or something like that and buy this roll of plastic and roll it out. It’s got two wires connected to it, and you plug in your battery or your laptop and charge it up.”

“The grand total in terms of the thickness is about 400 nanometers, which is one ten-thousandth the thickness of a human hair. And yet, shine a light on it and you get electricity out of it. Now we’d like it to be a bit thicker. We have to keep them thin in order to get all of the electrical charge out of the device. But if you think about this as a sandwich structure, we’ve made this incredibly thin sandwich and then each of the layers in contact with each other have to be just right in terms of the chemical composition, the orientation of the molecules, how well they adhere to each of the underlying surfaces. And if I go in and change just one molecule layer, the composition – that’s at the level of 1 nanometer in thickness – I can take a good device and turn it into a bad device; I can take a bad device and turn it into a good device. That’s the kind of level of control that we need. And we don’t fully understand it.”

But the equipment available now – optical microscopes capable of imaging individual molecules and revealing their electrical properties and spatial orientation – are helping his team understand. His goal is to figure out how to have the molecules arrange themselves – every time – in a way to produce lots of electricity. “They have to all line up like little soldiers,” he said.

“We have to give you a technology that is going to look like an ink, like a blue ink, that you can spray down on one of these surfaces and the molecules at the nanometer level are going to say, ‘OK, we’re going to get organized this way,’ and in doing so, when I put that top electrode on and shine a light, I’ll get lots and lots of electricity out of there,” Armstrong said.

A high vacuum photoelectron spectrometer allows them to build each molecular layer, moving it within the vacuum to study it, and then continue with another molecular layer. Other tools, like a silicon microtip, which looks like a tiny phonograph needle, can be positioned to +/- 0.01 nanometers. “Well inside the diameter of a molecule,” he said. Bouncing a laser off the back of the tip yields an image. Passing current through the tip, they can map the electrical properties of molecules. All this can help them build a template to create the ideal array of the molecule assemblies.

Erin Ratcliff joined the team as a postdoctoral electrochemist with a doctorate from Iowa State. “My background wasn’t in solar cells at all,” she said. “I had to come here and had to learn everything, where grad students get it from Day One at the UA.”

She spoke of the business school curve, resembling a hockey stick, when progress begins to accelerate rapidly. “We’re right at the magic moment when the hockey stick starts to take off, when you go from flat to hockey stick. We’re right there. It’s exciting to read the literature and hope that, yes, we will take off. It will be exciting to look back and say ‘I was there for that.’”

 

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Solar cells, nanotech and plastics

This release involves using nanotechnology to help create that efficiently turn light into electricity, improving solar cells in the process.

The release:

Plastics that convert light to electricity could have a big impact

		IMAGE: David Ginger, a University of Washington associate professor of chemistry, displays the tiny probe for a conductive atomic force microscope, used to record photocurrents on scales of millionths of an… Click here for more information.

Researchers the world over are striving to develop organic solar cells that can be produced easily and inexpensively as thin films that could be widely used to generate electricity.

But a major obstacle is coaxing these carbon-based materials to reliably form the proper structure at the nanoscale (tinier than 2-millionths of an inch) to be highly efficient in converting light to electricity. The goal is to develop cells made from low-cost plastics that will transform at least 10 percent of the sunlight that they absorb into usable electricity and can be easily manufactured.

A research team headed by David Ginger, a University of Washington associate professor of chemistry, has found a way to make images of tiny bubbles and channels, roughly 10,000 times smaller than a human hair, inside plastic solar cells. These bubbles and channels form within the polymers as they are being created in a baking process, called annealing, that is used to improve the materials’ performance.

The researchers are able to measure directly how much current each tiny bubble and channel carries, thus developing an understanding of exactly how a solar cell converts light into electricity. Ginger believes that will lead to a better understanding of which materials created under which conditions are most likely to meet the 10 percent efficiency goal.

As researchers approach that threshold, nanostructured plastic solar cells could be put into use on a broad scale, he said. As a start, they could be incorporated into purses or backpacks to charge cellular phones or mp3 players, but eventually they could make in important contribution to the electrical power supply.

Most researchers make plastic solar cells by blending two materials together in a thin film, then baking them to improve their performance. In the process, bubbles and channels form much as they would in a cake batter. The bubbles and channels affect how well the cell converts light into electricity and how much of the electric current actually gets to the wires leading out of the cell. The number of bubbles and channels and their configuration can be altered by how much heat is applied and for how long.

The exact structure of the bubbles and channels is critical to the solar cell’s performance, but the relationship between baking time, bubble size, channel connectivity and efficiency has been difficult to understand. Some models used to guide development of plastic solar cells even ignore the structure issues and assume that blending the two materials into a film for solar cells will produce a smooth and uniform substance. That assumption can make it difficult to understand just how much efficiency can be engineered into a polymer, Ginger said.

For the current research, the scientists worked with a blend of polythiophene and fullerene, model materials considered basic to organic solar cell research because their response to forces such as heating can be readily extrapolated to other materials. The materials were baked together at different temperatures and for different lengths of time.

Ginger is the lead author of a paper documenting the work, published online last month by the American Chemical Society journal Nano Letters and scheduled for a future print edition. Coauthors are Liam Pingree and Obadiah Reid of the UW. The research was funded by the National Science Foundation and the U.S. Department of Energy.

Ginger noted that the polymer tested is not likely to reach the 10 percent efficiency threshold. But the results, he said, will be a useful guide to show which new combinations of materials and at what baking time and temperature could form bubbles and channels in a way that the resulting polymer might meet the standard.

Such testing can be accomplished using a very small tool called an atomic force microscope, which uses a needle similar to the one that plays records on an old-style phonograph to make a nanoscale image of the solar cell. The microscope, developed in Ginger’s lab to record photocurrent, comes to a point just 10 to 20 nanometers across (a human hair is about 60,000 nanometers wide). The tip is coated with platinum or gold to conduct electrical current, and it traces back and forth across the solar cell to record the properties.

As the microscope traces back and forth over a solar cell, it records the channels and bubbles that were created as the material was formed. Using the microscope in conjunction with the knowledge gained from the current research, Ginger said, can help scientists determine quickly whether polymers they are working with are ever likely to reach the 10 percent efficiency threshold.

Making solar cells more efficient is crucial to making them cost effective, he said. And if costs can be brought low enough, solar cells could offset the need for more coal-generated electricity in years to come.

“The solution to the energy problem is going to be a mix, but in the long term solar power is going to be the biggest part of that mix,” he said.

 

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Nanophotonics market may reach $40B in five years

A release from the inbox:

Global Nanophotonic Market Worth US$37.6 Billion by 2014

WILMINGTON, Delaware, July 23/PRNewswire/ –     According to a new market research report, ‘Nanophotonics – Advanced
Technologies and Global Market (2009-2014)’, published by MarketsandMarkets
(http://www.marketsandmarkets.com), the global nanophotonics market is
expected to be worth US$3.6 billion by 2014, out of which the Asian market
will account for nearly 74% of the total revenues. The global market is
expected to record a CAGR of 100.7% from 2009 to 2014.

    Browse 134 market data tables and in-depth TOC on nanophotonics market.
Early buyers will receive 10% customization of reports
http://www.marketsandmarkets.com/Market-Reports/nanophotonics-advanced-techno
logies-and-global-market-125.html

    (Due to the length of the URL in the above paragraph, it may be necessary
 to copy and paste this hyperlink into your Internet browser’s URL address
field. Remove the space if one exists.)

    Nanophotonics (http://www.marketsandmarkets.com/Market-Reports/
nanophotonics-advanced-technologies-and-global-market-125.html) is born out
of the combination of three major sciences:photonics, nanotechnology,
and optoelectronics. While photonics and optoelectronics have revolutionized
the electronics and semiconductors market, nanotechnology has the greatest
potential for further improvement, and hence has emerged as the most
sought-after technology by big companies and research laboratories. In spite
of it being in the nascent stage, nanophotonics is expected to make it to
the mainstream market owing to the higher power efficiency, thermal
resistivity, and operational life.

    (Due to the length of the URL in the above paragraph, it may be necessary
 to copy and paste this hyperlink into your Internet browser’s URL address
field. Remove the space if one exists.)

    The nanophotonic component market is growing at a robust rate for the
last few years and is expected to maintain a very high CAGR for the next few
years. The market is expected to reach US$3.6 billion in 2014 at a CAGR of
100.7% from 2009 to 2014.

    Asia holds a major share of the global nanophotonics market. However, the
U.S. and Europe represent very high growth rate of 161.1% and 160.0%,
respectively, from 2009 to 2014. The U.S. and Europe assume further
importance because of the large consumer base for the nanophotonic devices.
Extensive investment in research and development for the application of
nanophotonics in increasing number of application areas has become the main
driver for this market

    The LED market is the largest segment; and is expected to reach US$2.7
billion by 2014 at a CAGR of 91.3%. Optical amplifier and holographic memory
device markets are estimated to record growth rate of 239% and 234.6%
respectively from 2009 to 2014. The high growth rate of nanophotonics
products is mainly due to high demand from Asian countries.

    The Asian market is the largest geographical segment; and is expected to
be worth US$2.7 billion by 2014. The second largest segment is Europe, with a
CAGR of 160.0%. However, market size of the U.S. is expected to increase at
the highest CAGR of 161.1% from the year 2009 to 2014.

    The report is titled ‘Nanophotonics- Advanced Technologies and Global
Market (2009 – 2014)’ and was published in June 2009.

    Scope of the Report

    This report aims to identify and analyze products, applications and
ingredients for nanophotonics market. The report segments the nanophotonics
product market as follows:

    Nanophotonics components – products

    Nanophotonic LED, nanophotonic OLED, nanophotonic near field optics,
nanophotonic photovoltaic cells, nanophotonic optical amplifiers,
nanophotonic optical switches and nanophotonic holographic data storage
system.

    Nanophotonics – applications
    Indicators and signs, lighting, non-visual applications,
telecommunications, entertainment and consumer electronics

    Nanophotonics – ingredients

Photonic crystals, plasmonics, nanotubes, nanoribbons and quantum dots.

    About MarketsandMarkets

    MarketsandMarkets is a research and consulting firm that publishes 120
market research (http://www.marketsandmarkets.com/) reports per year. Each
strategically analyzed report contains 250 pages of valuable market data,
including more than 100 market data summary tables and in-depth, five-level
segmentation for each of the products, services, applications, technologies,
ingredients and stakeholders categories. Our reports also analyze about 200
patents, over 50 companies and micro markets that are mutually exclusive and
collectively exhaustive. Browse all our 120 titles at
http://www.marketsandmarkets.com.

Source: MarketsandMarkets

CIGS-based solar cells ready for prime time

If CIGS-based solar cells are ready for commercial production this could be a major solar power breakthrough.

The release:

Low-cost solution processing method developed for CIGS-based solar cells

The method could provide an answer to a manufacturing issue

Though the solar industry today predominately produces solar panels made from crystalline silicon, they remain relatively expensive to make. New players in the solar industry have instead been looking at panels that can harvest energy with CIGS (copper-indium-gallium-selenide) or CIGS-related materials. CIGS panels have a high efficiency potential, may be cheaper to produce and would use less raw materials than silicon solar panels. But unfortunately, manufacturing of CIGS panels on a commercial scale has thus far proven to be difficult.

Recently researchers at the UCLA Henry Samueli School of Engineering and Applied Science have developed a low-cost solution processing method for CIGS-based solar cells that could provide an answer to the manufacturing issue. In a new study to be published in the journal Thin Solid Films on July 7, Yang Yang, a professor in the school’s Department of Materials Science and Engineering, and his research team show how they have developed a low-cost solution processing method for their copper-indium-diselenide solar cells which have the potential to be produced on a large scale.

“This CIGS-based material can demonstrate very high efficiency,” said William Hou, a graduate student on Yang’s team and first author of the study. “People have already demonstrated efficiency levels of up to 20 percent, but the current processing method is costly. Ultimately the cost of fabricating the product makes it difficult to be competitive with current grid prices. However, with the solution process that we recently developed, we can inherently reach the same efficiency levels and bring the cost of manufacturing down quite significantly.”

The copper-indium-diselenide thin-film solar cell developed by Yang’s team achieved 7.5 percent efficiency in the published study but has in a short amount of time already improved to 9.13 percent in the lab.

“We started this process 16 months ago from ground zero. We spent three to four months getting the material to reach 1 percent and today it’s around 9 percent. That is about an average increase of 1 percent every two months,” said Yang, also a member of the California NanoSystems Institute, where some of the work is being done.

Currently, most CIGS solar cells are produced using vacuum evaporation techniques called co-evaporation, which can be costly and time-consuming. The active elements — copper, indium, gallium and selenide — are heated and deposited onto a surface in a vacuum. Using vacuum processing to create CIGS films with uniform composition on a large scale has also been challenging.

The copper-indium-diselenide material created by Yang’s team does not need to go through the vacuum evaporation process. Their material is simply dissolved into a liquid, applied and baked. To prepare the solution, Yang’s team used hydrazine as the solvent to dissolve copper sulfide and indium selenide in order to form the constituents for the copper-indium-diselenide material. In solar cells, the “absorber layer” (either copper-indium-diselenide or CIGS) itself is the most critical to performance and the most difficult to control. Their copper-indium-diselenide layer, which is in solution form, can be easily painted or coated evenly onto a surface and baked.

“In our method, material utilization is one advantage. Another advantage is our solution technology has the potential to be fabricated in a continuous roll-to-roll process. Both are important breakthroughs in terms of cost,” said Hou.

The team’s goal is to reach an efficiency level of 15 to 20 percent. Yang predicts three to four years before commercialization.

“As we continue to work on enhancing the performance and efficiency of the solar cells, we also look forward to opportunities to collaborate with industry in order to develop this technology further. We hope this technology will lead to a new green energy company in the U.S., especially here in California so that it may also bring job opportunities to many who need it,” said Yang.

 

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The study was funded in part by the NSF Integrative Graduate Education and Research Traineeship-Materials Creation Training Program.

The Department of Materials Science and Engineering is part of the UCLA Henry Samueli School of Engineering and Applied Science, established in 1945, offers 28 academic and professional degree programs, including an interdepartmental graduate degree program in biomedical engineering. Ranked among the top 10 engineering schools at public universities nationwide, the school is home to five multimillion-dollar interdisciplinary research centers in wireless sensor systems, nanotechnology, nanomanufacturing and nanoelectronics, all funded by federal and private agencies.

Turning Buckyballs into Buckywires

Buckyballs are a nanotech that seems to be rarely discussed these days with all the breakthroughs in other areas. Scientists at the University of Cambridge have found a way to turn Buckyballs into Buckywires through polymerization. This steps adds to the utility of Buckyballs considerably. Buckywires should be better than carbon nanotubes in price and possibly performance.

From the link:

The trick that Geng and co have found is a way to connect two buckyballs together using a molecule of 1,2,4-trimethylbenzene–a colorless aromatic hydrocarbon. Repeat that and you’ve got a way to connect any number of buckyballs. And to prove it, the researchers have created and studied these buckywires in their lab, saying that the wires are highly stable.

Buckywires ought to be handy for all kinds of biological, electrical, optical, and magnetic applications. The gist of the paper is that anything that traditional carbon nanotubes can do, buckywires can do better. Or at least more cheaply.

The exciting thing about this breakthrough is the potential to grow buckywires on an industrial scale from buckyballs dissolved in a vat of bubbling oil. Since the buckywires are insoluble, they precipitate out, forming crystals. (Here it ought to be said that various other groups are said to have made buckywires of one kind or another, but none seem to have nailed it from an industrial perspective.)

Shape of cobalt nanoparticles affects behavior

Interesting nanotech news from the NIST.

The release:

Shape matters in the case of cobalt nanoparticles

		IMAGE: These cubes of cobalt (left/top), measuring about 50 nanometers wide, are showing scientists that, on the nanoscale, a change in shape is a change in property. Unlike smaller spherical cobalt… Click here for more information.

Shape is turning out to be a particularly important feature of some commercially important nanoparticles—but in subtle ways. New studies* by scientists at the National Institute for Standards and Technology (NIST) show that changing the shape of cobalt nanoparticles from spherical to cubic can fundamentally change their behavior.

Building on a previous paper** that examined the properties of cobalt formed into spheres just a few nanometers in diameter, the new work explores what happens when the cobalt is synthesized instead as nanocubes. Nanoparticles of cobalt possess large magnetic moments—a measure of magnetic strength—and unique catalytic properties, and have potential applications in information storage, energy and medicine.

One striking difference is the behavior of the two different particle types when external magnetic fields are applied and then removed. In the absence of a magnetic field, both the spherical and cubic nanoparticles spontaneously form chains—lining up as a string of microscopic magnets. Then, when placed in an external magnetic field, the individual chains bundle together in parallel lines to form thick columns aligned with the field. These induced columns, says NIST physicist Angela Hight Walker, imply that the external magnetic fields have a strong impact on the magnetic behavior of both nanoparticle shapes.

But their group interactions are somewhat different. As the strength of the external field is gradually reduced to zero, the magnetization of the spherical nanoparticles in the columns also decreases gradually. On the other hand, the magnetization of the cubic particles in the columns decreases in a much slower fashion until the particles rearrange their magnetic moments from linear chains into small circular groups, resulting in a sudden drop in their magnetization.

The team also showed that the cubes can be altered merely by observing with one of nanotechnology’s microscopes of choice. After a few minutes’ exposure to the illuminating beam of a transmission electron microscope, the nanocubes melt together, forming “nanowires” that are no longer separable as individual nanoparticles. The effect, not observed with the spheres, is surprising because the cubes average 50 nm across, much larger than the spheres’ 10 nm diameters. “You might expect the smaller objects to have a lower melting point,” Hight Walker says. “However, the sharp edges and corners in the nanocubes could be the locations to initiate melting.”

While Walker says that the melting effect could be a potential method for fabricating nanostructures, it also demands further attention. “This newfound effect demonstrates the need to characterize the physico-chemical properties of nanoparticles extremely well in order to pursue their applications in biology and medicine,” she says.

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 * G. Cheng, R.D. Shull and A.R. Hight Walker. Dipolar chains formed by chemically synthesized cobalt nanocubes. Journal of Magnetism and Magnetic Materials, May 11, 2009, Vol. 321, issue 10, pp. 1351—1355.

** G. Cheng, D. Romero, G.T. Fraser and A.R. Hight Walker. Magnetic-field-induced assemblies of cobalt nanoparticles. Langmuir, December 2005. See Oct. 20, 2007, Tech Beat article, “Magnetic Nanoparticles Assembled into Long Chains”.

Graphene beats copper in IC connections

It’s been a while since I’ve had the chance to blog about graphene, but here is the latest on the carbon nanomaterial.  (Be sure to hit the second link for images.)

The release:

Graphene May Have Advantages Over Copper for Future IC Interconnects

New Material May Replace Traditional Metal at Nanoscale Widths

Atlanta (June 4, 2009) —The unique properties of thin layers of graphite—known as graphene—make the material attractive for a wide range of potential electronic devices. Researchers have now experimentally demonstrated the potential for another graphene application: replacing copper for interconnects in future generations of integrated circuits.

In a paper published in the June 2009 issue of the IEEE journal Electron Device Letters, researchers at the Georgia Institute of Technology report detailed analysis of resistivity in graphene nanoribbon interconnects as narrow as 18 nanometers.

The results suggest that graphene could out-perform copper for use as on-chip interconnects—tiny wires that are used to connect transistors and other devices on integrated circuits. Use of graphene for these interconnects could help extend the long run of performance improvements for silicon-based integrated circuit technology.

“As you make copper interconnects narrower and narrower, the resistivity increases as the true nanoscale properties of the material become apparent,” said Raghunath Murali, a research engineer in Georgia Tech’s Microelectronics Research Center and the School of Electrical and Computer Engineering. “Our experimental demonstration of graphene nanowire interconnects on the scale of 20 nanometers shows that their performance is comparable to even the most optimistic projections for copper interconnects at that scale. Under real-world conditions, our graphene interconnects probably already out-perform copper at this size scale.”

Beyond resistivity improvement, graphene interconnects would offer higher electron mobility, better thermal conductivity, higher mechanical strength and reduced capacitance coupling between adjacent wires.

“Resistivity is normally independent of the dimension—a property inherent to the material,” Murali noted. “But as you get into the nanometer-scale domain, the grain sizes of the copper become important and conductance is affected by scattering at the grain boundaries and at the side walls. These add up to increased resistivity, which nearly doubles as the interconnect sizes shrink to 30 nanometers.”

The research was supported by the Interconnect Focus Center, which is one of the Semiconductor Research Corporation/DARPA Focus Centers, and the Nanoelectronics Research Initiative through the INDEX Center.

Murali and collaborators Kevin Brenner, Yinxiao Yang, Thomas Beck and James Meindl studied the electrical properties of graphene layers that had been taken from a block of pure graphite. They believe the attractive properties will ultimately also be measured in graphene fabricated using other techniques, such as growth on silicon carbide, which now produces graphene of lower quality but has the potential for achieving higher quality.

Because graphene can be patterned using conventional microelectronics processes, the transition from copper could be made without integrating a new manufacturing technique into circuit fabrication.

“We are optimistic about being able to use graphene in manufactured systems because researchers can already grow layers of it in the lab,” Murali noted. “There will be challenges in integrating graphene with silicon, but those will be overcome. Except for using a different material, everything we would need to produce graphene interconnects is already well known and established.”

Experimentally, the researchers began with flakes of multi-layered graphene removed from a graphite block and placed onto an oxidized silicon substrate. They used electron beam lithography to construct four electrode contacts on the graphene, then used lithography to fabricate devices consisting of parallel nanoribbons of widths ranging between 18 and 52 nanometers. The three-dimensional resistivity of the nanoribbons on 18 different devices was then measured using standard analytical techniques at room temperature.

The best of the graphene nanoribbons showed conductivity equal to that predicted for copper interconnects of the same size. Because the comparisons were between non-optimized graphene and optimistic estimates for copper, they suggest that performance of the new material will ultimately surpass that of the traditional interconnect material, Murali said.

“Even graphene samples of moderate quality show excellent properties,” he explained. “We are not using very high levels of optimization or especially clean processes. With our straightforward processing, we are getting graphene interconnects that are essentially comparable to copper. If we do this more optimally, the performance should surpass copper.”

Though one of graphene’s key properties is reported to be ballistic transport—meaning electrons can flow through it without resistance—the material’s actual conductance is limited by factors that include scattering from impurities, line-edge roughness and from substrate phonons—vibrations in the substrate lattice.

Use of graphene interconnects could help facilitate continuing increases in integrated circuit performance once features sizes drop to approximately 20 nanometers, which could happen in the next five years, Murali said. At that scale, the increased resistance of copper interconnects could offset performance increases, meaning that without other improvements, higher density wouldn’t produce faster integrated circuits.

“This is not a roadblock to achieving scaling from one generation to the next, but it is a roadblock to achieving increased performance,” he said. “Dimensional scaling could continue, but because we would be giving up so much in terms of resistivity, we wouldn’t get a performance advantage from that. That’s the problem we hope to solve by switching to a different materials system for interconnects.”

Nanoantennas

Sounds like some nanotech with potential.

The release:

Bridging the gap in nanoantennas

		IMAGE: The bottom line depicts the topography, whereas the upper line plots the scanned near-field images. Figure a shows a metal nanorod that can be considered the most simple dipole antenna…. Click here for more information.

In a recent publication in Nature Photonics, a joint team of researchers at CIC nanoGUNE, Donostia International Physics Center DIPC, Centro de Física de Materiales of CSIC/UPV-EHU in San Sebastian (Spain), Harvard University (USA) and the Max Planck Institute of Biochemistry in Munich (Germany) reports an innovative method for controlling light on the nanoscale by adopting tuning concepts from radio-frequency technology. The method opens the door for targeted design of antenna-based applications including highly sensitive biosensors and extremely fast photodetectors, which could play an important role in future biomedical diagnostics and information processing.

An antenna is a device designed to transmit or receive electromagnetic waves. Radio frequency antennas find wide use in systems such as radio and television broadcasting, point-to-point radio communication, wireless LAN, radar, and space exploration. In turn, an optical antenna is a device which acts as an effective receiver and transmitter of visible or infrared light. It has the ability to concentrate (focus) light to tiny spots of nanometer-scale dimensions, which is several orders of magnitude smaller than what conventional lenses can achieve. Tiny objects such as molecules or semiconductors that are placed into these so-called “hot spots” of the antenna can efficiently interact with light. Therefore optical antennas boost single molecule spectroscopy or signal-to-noise in detector applications.

In their experiments the researchers studied a special type of infrared antennas, featuring a very narrow gap at the center. These so called gap-antennas generate a very intense “hot spot” inside the gap, allowing for highly efficient nano-focusing of light. To study how the presence of matter inside the gap (the “load”) affects the antenna behavior, the researchers fabricated small metal bridges inside the gap (Figure b). They mapped the near-field oscillations of the different antennas with a modified version of the scattering-type near-field microscope that the Max Planck and nanoGUNE researchers had pioneered over the last decade. For this work, they chose dielectric tips and operated in transmission mode, allowing for imaging local antenna fields in details as small as 50 nm without disturbing the antenna. “By monitoring the near-field oscillations of the different antennas with our novel near-field microscope, we were able to directly visualize how matter inside the gap affects the antenna response. The effect could find interesting applications for tuning of optical antennas” says Rainer Hillenbrand leader of the Nanooptics group at the newly established research institute CIC nanoGUNE Consolider.

The nanooptics group from DIPC and CSIC-UPV/EHU led by Javier Aizpurua in San Sebastián fully confirmed and helped to understand the experimental results by means of full electrodynamic calculations. The calculated maps of the antenna fields are in good agreement with the experimentally observed images. The simulations add deep insights into the dependence of the antenna modes on the bridging, thus confirming the validity and robustness of the “loading” concept to manipulate and control nanoscale local fields in optics.

Furthermore, the researchers applied the well developed radio–frequency antenna design concepts to visible and infrared frequencies, and explained the behavior of the loaded antennas within the framework of optical circuit theory. A simple circuit model showed remarkable agreement with the results of the numerical calculations of the optical resonances. “By extending circuit theory to visible and infrared frequencies, the design of novel photonic devices and detectors will become more efficient. This bridges the gap between these two disciplines” says Javier Aizpurua.

With this work, the researches provide first experimental evidence that the local antenna fields can be controlled by gap-loading. This opens the door for designing near-field patterns in the nanoscale by load manipulation, without the need to change antenna length, which could be highly valuable for the development of compact and integrated nanophotonic devices.

 

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Nanotech improves transistor chips

Nanotechnology offers fairly regular breakthroughs in chip tech. Here’s the latest.

The release:

Self-assembled nanowires could make chips smaller and faster

CHAMPAIGN, Ill. — Researchers at the University of Illinois have found a new way to make transistors smaller and faster. The technique uses self-assembled, self-aligned, and defect-free nanowire channels made of gallium arsenide.

In a paper to appear in the IEEE (Institute of Electrical and Electronics Engineers) journal Electron Device Letters, U. of I. electrical and computer engineering professor Xiuling Li and graduate research assistant Seth Fortuna describe the first metal-semiconductor field-effect transistor fabricated with a self-assembled, planar gallium-arsenide nanowire channel.

Nanowires are attractive building blocks for both electronics and photonics applications. Compound semiconductor nanowires, such as gallium arsenide, are especially desirable because of their better transport properties and versatile heterojunctions. However, a number of challenges – including integration with existing microelectronics – must first be overcome.

“Our new planar growth process creates self-aligned, defect-free gallium-arsenide nanowires that could readily be scaled up for manufacturing purposes,” said Li, who also is affiliated with the university’s Micro and Nanoelectronics Laboratory and the Beckman Institute. “It’s a non-lithographic process that can precisely control the nanowire dimension and orientation, yet is compatible with existing circuit design and fabrication technology.”

The gallium-arsenide nanowire channel used in the researchers’ demonstration transistor was grown by metal organic chemical vapor deposition using gold as a catalyst. The rest of the transistor was made with conventional microfabrication techniques.

While the diameter of the transistor’s nanowire channel was approximately 200 nanometers, nanowires with diameters as small as 5 nanometers can be made with the gold-catalyzed growth technique, the researchers report. The self-aligned orientation of the nanowires is determined by the crystal structure of the substrate and certain growth parameters.

In earlier work, Li and Fortuna demonstrated they could grow the nanowires and then transfer-print them on other substrates, including silicon, for heterogeneous integration. “Transferring the self-aligned planar nanowires while maintaining both their position and alignment could enable flexible electronics and photonics at a true nanometer scale,” the researchers wrote in the December 2008 issue of the journal Nano Letters.

In work presented in the current paper, the researchers grew the gallium-arsenide nanowire channel in place, instead of transferring it. In contrast to the common types of non-planar gallium arsenide nanowires, the researchers’ planar nanowire was free from twin defects, which are rotational defects in the crystal structure that decrease the mobility of the charge carriers.

“By replacing the standard channel in a metal-semiconductor field-effect transistor with one of our planar nanowires, we demonstrated that the defect-free nanowire’s electron mobility was indeed as high as the corresponding bulk value,” Fortuna said. “The high electron mobility nanowire channel could lead to smaller, better and faster devices.”

Considering their planar, self-aligned and transferable nature, the nanowire channels could help create higher performance transistors for next-generation integrated circuit applications, Li said.

The high quality planar nanowires can also be used in nano-injection lasers for use in optical communications.

The researchers are also developing new device concepts driven by further engineering of the planar one-dimensional nanostructure.

 

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The work was supported by the National Science Foundation.