David Kirkpatrick

February 18, 2010

Graphene replacing silicon — is it “when” and not “if?”

Not quite yet, but headway is being made in making graphene the successor to silicon as the semiconductor for electronics. I first blogged about graphene replacing silicon back in late March 2008 (this blog wasn’t even three months old at the time — hit the link and dig the crazy layout I was using for KurzweilAI posts).

From the first link, the latest news — both good and bad — in making graphene the semiconductor of choice:

“Graphene has been the subject of intense focus and research for a few years now,” Philip Kim tells PhysOrg.com. “There are researchers that feel that it is possible that graphene could replace silicon as a semiconductor in electronics.”

Kim is a scientist at Columbia University in New York City. He has been working with Melinda Han and Juliana Brant to try and come up with a way to make  a feasible replacement for silicon. Toward that end, they have been looking at ways to overcome some of the problems associated with using graphene as a semiconductor in . They set forth some ideas for electron transport for graphene in : “ in Disordered Graphene Nanoribbons.”

“Graphene has high mobility, and less scattering than silicon. Theoretically, it is possible to make smaller structures that are more stable at the nanolevel than those made from silicon,” Kim says. He points out that as electronics continue to shrink in size, the interest in finding viable alternatives to silicon is likely to increase. Graphene is a good candidate because of the high  it offers, its stability on such a small scale, and the possibility that one could come up with different device concepts for electronics.

And here’s a bonus fun graphene graphic from the link:

Graphene A

Graphene is an atomic-scale honeycomb lattice made of carbon atoms. By Dr. Thomas Szkopek, via Wikipedia

September 8, 2008

Is graphene going to be the new semiconductor?

Filed under: Science, Technology — Tags: , , , , , — David Kirkpatrick @ 10:22 pm

Here’sa report from PhysOrg on graphene replacing semiconductors in the next generation computer chip:

When one looks at the structure of graphite, stacked layers of pure carbon are apparent. However, it wasn’t until 2004 that a process sophisticated enough to “slice” off one of the layers was discovered. This single layer is called graphene. Graphene is basically a sheet of bonded carbon atoms, with the thickness of only one atom. If one could look down at graphene from the top, one would observe that the sheet bears a strong resemblance to honeycomb, with its hexagons fitted snugly together.

“Graphene behaves almost like semiconductor but without a energy gap,” Kim explains. This is why it would do well as a material for computer chips. “When you apply an electric field perpendicular to graphene, the number of electrons – the carrier density – can be tuned.”

“One of the main themes is how fast the charge can move in graphene,” Kim continues. “Higher mobility means electron conducts faster in the system. It has always been speculated that the mobility of graphene can be quite high. But it has not been shown as high as some of the highest semiconductors in the past.”

August 23, 2008

New online tool for investors

Here’s the release on a study published the Journal of Consumer Research:

How much risk can you handle? Making better investment decisions

Many Americans make investment decisions with their retirement funds. But they don’t always make informed judgments. A new study in the Journal of Consumer Research introduces a new tool that investors can use to choose investments based on their financial goals and risk attitudes.

Authors Daniel G. Goldstein (London Business School), Eric J. Johnson (Columbia University), and William F. Sharpe (Stanford University) developed a tool, which they call the Distribution Builder. With brief training, people can use the Distribution Builder to better understand their investment goals and trade-offs.

“We think that the Distribution Builder can function like a flight simulator, allowing investors to explore the outcomes of their decisions with only virtual outcomes,” write the authors.

The Distribution Builder is an online tool that estimates the level of risk a user considers unacceptable in his or her investments by using a probability distribution. Since many employees make retirement investment decisions without understanding the complex picture of their own risk preferences, the Distribution Builder is a novel way for people to uncover their preexisting preferences. And, according to the researchers, it can also help people construct better preferences.

The researchers claim that by using the tool, investors can become more actively involved in the process of deciding where and how much to invest. They also believe investment management companies could use the tool to better serve their investors.

The Distribution Builder may have applications that reach beyond retirement investments. “Beyond financial services, the basic DB framework could be used to study other consumer choices in which there is a risk-reward tradeoff, including waiting times at health clinics (or on customer support lines), delivery times of packages, and overage charges for mobile-phone plans,” they conclude.

 

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Daniel G. Goldstein, Eric J. Johnson, and William F. Sharpe. “Choosing Outcomes Versus Choosing Products: Consumer-Focused Retirement Investment Advice” Journal of Consumer Research: October 2008.

July 18, 2008

Stronger than … well, anything!

Filed under: Science, Technology — Tags: , , , , — David Kirkpatrick @ 2:32 pm

From KurzweilAI.net, strain measurement testing has shown graphene to be the strongest material ever tested.

Strongest Material Ever Tested
Technology Review, July 17, 2008

In a strain measurement using perfect samples of graphene, Columbia University researchers have confirmed that is the strongest material ever tested.


Illustration showning the one-atom-thick atomic structure of graphene (Jeffrey Kysar, Columbia University)

The finding provides evidence that graphene transistors could be the most effective material to withstand heat in future ultrafast microprocessors.

 
Read Original Article>>

June 23, 2008

A couple of solar breaktroughs

From KurzweilAI.net — MIT students create a low-cost, low-tech solar dish, and carbon nanotubes may lower the cost and improve the performance of solar cells.

MIT team plays with fire to create cheap energy
Christian Science Monitor, June 18, 2008

A simple new low-cost solar dish developed by MIT students produces steam heat for less than the cost of heat from oil or natural gas, according to the MIT team.

The steam heat can be used cost effectively for manufacturing, food pasteurization, and heating buildings.
 
Read Original Article>>

 

Perfecting a solar cell by adding imperfections
PhysOrg.com, June 16, 2008

New research at Santa Fe Institute, Michigan State University, and Columbia University shows that a film of carbon nanotubes may be able to replace two of the layers normally used in a solar cell, with improved performance at lower cost.

Exposing the carbon nanotubes to ozone made the carbon nanotubes better catalysts, with more than a ten-fold improvement, and replaced expensive platinum. And making them longer improved both conductivity and transparency.

The carbonnanotube films might also be used in fuel cells and batteries.

 
Read Original Article>>

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