David Kirkpatrick

November 2, 2010

Cool nanotech image — growing nanowires

Cool image and interesting process

nanotechnology image
In the growth of sapphire nanowires using the vapor-liquid-solid method, scientists have observed that a facet at the liquid-solid interface alternately grows and shrinks, which promotes nanowire growth. These images are from the video below. Image credit: Sang Ho Oh, et al.

From the link:

Nanowires can be grown in many ways, but one of the lesser-understood growth processes is vapor-liquid-solid (VLS) growth. In VLS, a vapor adsorbs onto a liquid droplet, and the droplet transports the vapor and deposits it as a crystal at a liquid-solid interface. As the process repeats, a nanowire is built one crystal at a time. One advantage of the VLS process is that it allows scientists to control the nanowire’s growth in terms of size, shape, orientation, and composition, although this requires understanding the growth mechanisms on the atomic scale. In a new study, scientists have investigated the steps involved in VLS growth, and have observed a new oscillatory behavior that could lead to better controlled nanowire growth.

Hit the link for a video of the process.

October 22, 2010

Cool nanotech image — graphene transistors

Filed under: et.al., Science — Tags: , , , , — David Kirkpatrick @ 9:34 am

The article connected to the image is pretty good, too.

Triple transistor: Single graphene transistors like this one can be made to operate in three modes and perform functions that usually require multiple transistors in a circuit.
Credit: Alexander Balandin

Also from the link:

Researchers have already made blisteringly fast graphene transistors. Now they’ve used graphene to make a transistor that can be switched between three different modes of operation, which in conventional circuits must be performed by three separate transistors. These configurable transistors could lead to more compact chips for sending and receiving wireless signals.

Chips that use fewer transistors while maintaining all the same functions could be less expensive, use less energy, and free up room inside portable electronics like smart phones, where space is tight. The new graphene transistor is an analog device, of the type that’s used for wireless communications in Bluetooth headsets and radio-frequency identification (RFID) tags.

 

October 16, 2010

Cool nanotech image — graphene

Filed under: et.al., Science, Technology — Tags: , , , , , — David Kirkpatrick @ 9:12 am

Actually the accompanying article is pretty cool, too, so do take the time to check it out.

But now, the image …

This image of a single suspended sheet of graphene taken with the TEAM 0.5, at Berkeley Lab’s National Center for Electron Microscopy shows individual carbon atoms (yellow) on the honeycomb lattice.

Also from the link:

In the current study, the team made graphene nanoribbons using a nanowire mask-based fabrication technique. By measuring the conductance fluctuation, or ‘noise’ of electrons in graphene nanoribbons, the researchers directly probed the effect of quantum confinement in these structures. Their findings map the electronic band structure of these graphene nanoribbons using a robust electrical probing method. This method can be further applied to a wide array of nanoscale materials, including graphene-based electronic devices.

“It amazes us to observe such a clear correlation between the noise and the band structure of these graphene nanomaterials,” says lead author Guangyu Xu, a physicist at University of California, Los Angeles. “This work adds strong support to the quasi-one-dimensional subband formation in graphene nanoribbons, in which our method turns out to be much more robust than conductance measurement.”

One more bit from the link, from the intro actually:

In last week’s announcement of the Nobel Prize in Physics, the Royal Swedish Academy of Sciences lauded graphene’s “exceptional properties that originate from the remarkable world of quantum physics.” If it weren’t hot enough before, this atomically thin sheet of carbon is now officially in the global spotlight.

So expect to hear a lot more about graphene in the coming months. Of course if you’re a regular reader of this blog, you’ve been getting a pretty steady (aside from the last month of light blogging) diet of graphene since almost day one (since February 2008 to be exact).

September 3, 2010

Cool nanotech image — a 2-water molecule thick ice crystal

Researchers used graphene to trap the room-temperature ice on a mica surface.

Atomic force micrograph of ~1 micrometer wide × 1.5 micrometers (millionths of a meter) tall area. The ice crystals (lightest blue) are 0.37 nanometers (billionths of a meter) high, which is the height of a 2-water molecule thick ice crystal. A one-atom thick sheet of graphene is used to conformally coat and trap water that has adsorbed onto a mica surface, permitting it to be imaged and characterized by atomic force microscopy. Detailed analysis of such images reveals that this (first layer) of water is ice, even at room temperature. At high humidity levels, a second layer of water will coat the first layer, also as ice. At very high humidity levels, additional layers of water will coat the surface as droplets. Credit: Heath group/Caltech

Hit the link for the full story on this image.

September 2, 2010

Cool nanotech image — the perfect nanocube

Check this out

Caption: These electron microscope images show perfect-edged nanocubes produced in a one-step process created at NIST that allows careful control of the cubes’ size, shape and composition.

Credit: NIST

Usage Restrictions: None

Related news release: The perfect nanocube: Precise control of size, shape and composition

And:

Caption: These electron microscope images show perfect-edged nanocubes produced in a one-step process created at NIST that allows careful control of the cubes’ size, shape and composition.

Credit: NIST

Usage Restrictions: None

Related news release: The perfect nanocube: Precise control of size, shape and composition

Head below the fold for the accompanying release: (more…)

August 26, 2010

Cool nanotech image — microneedles

Cool to look, even more cool when put into practice. Microneedles can deliver quantum dots into skin and should lead to new diagnosis and treatment of medical conditions such as skin cancer.

And now, the image:

Hollow microneedles open the door to new techniques for diagnosing and treating a variety of medical conditions, including skin cancer. Image reproduced by permission of the Royal Society of Chemistry.

For more on microneedles, here’s the full release.

May 1, 2010

Cool nanotech image — atomic moire pattern of graphene

Filed under: et.al., Science, Technology — Tags: , , , , , — David Kirkpatrick @ 5:11 pm

Check this out:

Caption: Moiré patterns appear when two or more periodic grids are overlaid slightly askew, which creates a new larger periodic pattern. Researchers from NIST and Georgia Tech imaged and interpreted the moiré patterns created by overlaid sheets of graphene to determine how the lattices of the individual sheets were stacked in relation to one another and to find subtle strains in the regions of bulges or wrinkles in the sheets.

Credit: NIST

Usage Restrictions: None

Related news release: Seeing moire in graphene

March 17, 2010

Amazing nanotech image — nanoparticle ribbons twisted by light

Truly amazing finding to go along with a very cool image:

After 72 hours of exposure to ambient light, strands of nanoparticles twisted and bunched together. Credit: Nicholas Kotov

Be sure and hit the link up there for the full release on this news, and for a very, very large version of this image.

March 2, 2010

Cool nanotech image — cadmium sulfide semiconducting laser

This image is part of the series linked in the previous post on the laser turning 50, but it deserves highlighting as a very cool nanotechnology image.

Researchers at the University of California, Berkeley, have created the smallest semiconducting laser, which could eventually be used for optical computing. A cadmium sulfide wire 50 nanometers in diameter generates visible light and holds it in a five-nanometer space.

Credit: Xiang Zhang Lab/UC Berkeley

November 21, 2009

Carbon nanotube supercapacitors

Flawed carbon nanotubes may lead to supercapacitors.

From the link:

Most people would like to be able to charge their cell phones and other personal electronics quickly and not too often. A recent discovery made by UC San Diego engineers could lead to carbon nanotube-based supercapacitors that could do just this.

In recent research, published in , Prabhakar Bandaru, a professor in the UCSD Department of Mechanical and Aerospace Engineering, along with graduate student Mark Hoefer, have found that artificially introduced defects in nanotubes can aid the development of supercapacitors.

“While batteries have large , they take a long time to charge; while electrostatic capacitors can charge quickly but typically have limited capacity. However, supercapacitors/electrochemical capacitors incorporate the advantages of both,” Bandaru said.

Of course I mostly ran this post just to add to the excuse for running this awesome image of a carbon nanotube. Earlier this week I featured an incredible image of graphene. We’re getting some just simply amazing looks into the atomic world right now. And it’ll only get better.

Carbon nanotubes could serve as supercapacitor electrodes with enhanced charge and energy storage capacity (inset: a magnified view of a single carbon nanotube).

Credit: UC San Diego

November 17, 2009

Incredible nanotech image — graphene

Filed under: et.al., Science, Technology — Tags: , , , , — David Kirkpatrick @ 10:02 pm

I’ve done lots of blogging on the nanomaterial graphene, and here’s an incredible image of the atom-thick sheet of carbon:

A graphene sheet stretched across a gap in a semiconductor chip. Image: Kirill Bolotkin

And here’s a link to the PhysOrg article accompanying the image.

From the link:

Not only is this the thinnest material possible, but it also is 10 times stronger than steel and it conducts electricity better than any other known material at room temperature. These and graphene’s other exotic properties have attracted the interest of physicists, who want to study them, and nanotechnologists, who want to exploit them to make novel electrical and mechanical devices.

“There are two features that make graphene exceptional,” says Kirill Bolotin, who has just joined the Vanderbilt Department of Physics and Astronomy as an assistant professor. “First, its molecular structure is so resistant to defects that researchers have had to hand-make them to study what effects they have. Second, the electrons that carry  travel much faster and generally behave as if they have far less mass than they do in ordinary metals or superconductors.”

November 16, 2009

Beautiful nanotech image — photovoltaic solar cell

This is a nice gallery of nanotech images from New Scientist. Here’s the description from the series, “Chemist George Whitesides has collaborated with MIT and Harvard photographer-in-residence Felice Frankel to produce No Small Matter, a book of images of the micro and nanoworld.”

From the first image, my favorite:

Sun catchers

This is a close-up of the top side of a photovoltaic solar cell. The cell converts the energy from the sun’s photons into electrical energy by taking advantage of the photo-electric effect. This cell is made of a wafer of crystalline silicon.

Light is absorbed by the wafer and creates charge that is collected by silver conductor lines, shown in the image as the gold-coloured strip. The cell is coated with silicon nitride which acts as an anti-reflective surface, preventing light energy from bouncing away and giving the cell its blue-violet colour.

Rather than attaching solar panels to our roofs, recent research suggests that in the future we could paint solar cells on to our houses, removing the need to rely on expensive silicon wafers.

(Image: Felice Frankel)

February 20, 2009

Smallest ever square nanotube

Very cool nanotech story and image from PhysOrg.

The image:

An electron microscope image of the smallest reported square-cross-section nanotube. Image courtesy Daniel Ugarte.

An electron microscope image of the smallest reported square-cross-section nanotube. Image courtesy Daniel Ugarte.

 

And from the link:

Scientists have observed the smallest reported nanotube that has a square cross-section. The structure formed spontaneously and unexpectedly when silver nanowires were stretched and is a reminder that scientists still have much more to learn about the nanoscale world.

The study was performed by scientists at two Brazilian institutions, the Laboratorio Nacional de Luz Sıncrotron (the Brazilian Synchrotron Light Laboratory) and the Universidade Estadual de Campinas-UNICAMP.

This research illustrates how material behavior at the nanoscale can be vastly and surprisingly different from the macroscopic scale, particularly in the case of applied mechanical stress. In general, the main differences between the behaviors of nanoscale and bulk materials are due to “surface energy.” In the physics of solid materials, surfaces must be less energetic than the rest of the material, lest surfaces be constantly created until the material become nothing but a single surface.

For nanostructures, surface energy is more powerful because there is such a small amount of the material. Scientists expect to see certain atomic behaviors, such as how the atoms order themselves, based on predictions of surface energy. But this work has shown that the addition of a mechanical stress, such as pulling, can produced unexpected results.

October 2, 2008

Nanoscale image of fuel-cell nanoparticle

It may not be pretty, but it is pretty cool.

From the link:

In a step toward developing better fuel cells for electric cars and more, engineers at MIT and two other institutions have taken the first images of individual atoms on and near the surface of nanoparticles key to the eco-friendly energy storage devices.

Nanoparticles made of platinum and cobalt are known to catalyze some of the chemical reactions behind fuel cells, making those reactions run up to four times faster than if platinum alone is used as the catalyst.

Left image highlights two platinum-cobalt catalyst nanoparticles (inside the dashed boxes) with a 'sandwich' structure of platinum and cobalt atoms near the surface. At right is a cross-sectional model corresponding to the lower particle, showing platinum atoms enriched in the outermost layer, cobalt enriched in the second, and additional layers containing a mixture of the two. (Image at left taken at Oak Ridge National Laboratory.) Image courtesy / Electrochemical Energy Laboratory at MIT

Left image highlights two platinum-cobalt catalyst nanoparticles (inside the dashed boxes) with a 'sandwich' structure of platinum and cobalt atoms near the surface. At right is a cross-sectional model corresponding to the lower particle, showing platinum atoms enriched in the outermost layer, cobalt enriched in the second, and additional layers containing a mixture of the two. (Image at left taken at Oak Ridge National Laboratory.) Image courtesy / Electrochemical Energy Laboratory at MIT

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