Friday, October 25, 2013

All graphene computer chips designed in a research paper

All graphene computer chips designed in a research paper

For now, UCSB’s design is just that — a computer model that should technically work, but which hasn’t been built yet. In theory, though, with the worldwide efforts to improve high-quality graphene production and patterning, we should be able to build an all-graphene IC in the next few years. Even then, though, it will still take a long time to go from laboratory prototype to full-scale commercial production — perhaps a decade or more. For the time being, the higher electron mobility of III-V semiconductors compared to silicon should provide a stopgap solution for the continuing miniaturization and ultra-low-power requirements of modern computing. When graphene ICs do finally take off, though, we have terahertz switching speeds and transistor densities in the tens-of-billions to look forward to.

Proposal for all-graphene monolithic logic circuits


ABSTRACT

Since the very inception of integrated circuits, dissimilar materials have been used for fabricating devices and interconnects. Typically, semiconductors are used for devices and metals are used for interconnecting them. This, however, leads to a “contact resistance” between them that degrades device and circuit performance, especially for nanoscale technologies. This letter introduces and explores an “all-graphene” device-interconnect co-design scheme, where a single 2-dimensional sheet of monolayer graphene is proposed to be monolithically patterned to form both active devices (graphene nanoribbon tunnel-field-effect-transistors) as well as interconnects in a seamless manner. Thereby, the use of external contacts is alleviated, resulting in substantial reduction in contact parasitics. Calculations based on tight-binding theory and Non-Equilibrium Green's Function (NEGF) formalism solved self-consistently with the Poisson's equation are used to analyze the intricate properties of the proposed structure. This constitutes the first NEGF simulation based demonstration that devices and interconnects can be built using the “same starting material” – graphene. Moreover, it is also shown that all-graphene circuits can surpass the static performances of the 22 nm complementary metal-oxide-semiconductor devices, including minimum operable supply voltage, static noise margin, and power consumption.

Wednesday, October 2, 2013

KTH | Battery low? Give your mobile some water

KTH | Battery low? Give your mobile some water

Based on micro fuel cell technology developed at KTH Royal Institute of Technology in Stockholm, the MyFC PowerTrekk uses ordinary water to extend battery life for devices of up to 3 watts.
Anders Lundblad, KTH researcher and founder of MyFC, says that the device can be powered by fresh or seawater. The water need not be completely clean.
“Our invention has great potential to accelerate social development in emerging markets,” Lundblad says. “There are large areas that lack electricity, while mobile phones fulfil more and more vital functions, such as access to weather information or electronic payment.”
A USB connector attaches the compact PowerTrekk charger to the device. When plain water is poured onto a small recyclable metal disc inside the unit, hydrogen gas is released and combines with oxygen to convert chemical energy into electrical energy. The resulting charge is enough to power an iPhone to between 25 and 100 per cent of its battery capacity.
Lundblad has done research on micro fuel cells and small flat Proton Exchange Membrane (PEM) fuel cells for more than 15 years at the Department of Applied Electrochemistry at KTH. He says the business vision behind MyFC is to commercialise fuel cell technology and contribute to the development of environmental technology.
He says the charger is the first step toward building fuel cells in laptops.
“The launch of our charger is a strategic move to gain wide acceptance of fuel cells throughout society,” he says. “Our chargers may be considered expensive now; but in the longer term, as they reach a mass market, they would go down in price.”
Fuel cells can already be found in electric cars, trucks and buses, and backup electrical power supply systems for hospitals and cogeneration plants. The process by which fuel cells generate electricity is considered to be safe and environmentally-friendly, and the only by-product is water vapour. The fuel cell system is passive and has no fans or pumps.
Lundblad says that fuel cell chargers are faster and more reliable than solar chargers. The main target groups for MyFC PowerTrekk are those who travel or live in remote areas of the world, outdoor enthusiasts and aid workers, he says.
The charger is both a fuel cell and a portable battery, providing a direct power source as well as a storage buffer for the fuel.
MyFC plans to open an online shop for its MyFC PowerTrekk product. The company has already sold the technology to users in China, Japan, the U.S. and much of Europe.
For more information contact Anders Lundblad on anders.lundblad @ myfc.se.
Katarina Ahlfort

Japanese start-up plans hydrogen fuel cell for 2014 - Batteries / fuel cells, Components, Rohm, Aquafairy, CEATEC - Computerworld

Japanese start-up plans hydrogen fuel cell for 2014 - Batteries / fuel cells, Components, Rohm, Aquafairy, CEATEC - Computerworld

A Japanese start-up says it has finessed a technology that could finally make consumer-grade fuel cells a reality. If successful, the company, Aquafairy, would create a business where many much larger companies have failed.
Prototypes of the company's hydrogen fuel cell technology are on show this week at the Ceatec exhibition in Japan where the company's president, Mike Aizawa, said he hopes the first products will be on sale next year.
The promise of fuel cells is attractive: instantly available electricity from a safe, disposable fuel cartridge. They are typically seen as a way to provide electricity where there is no power grid, when electricity supply has failed or, in a portable package, for on-the-go charging of gadgets such as smartphones or tablets.
Japan's major electronics companies went through a period of several years beginning around 2005 when they showed prototype fuel cells, but none of them ever managed to reach the market and much of that research appears to have ended.
"They all failed because they used Methanol," said Aizawa in an interview with the IDG News Service. "They couldn't figure out a way to do it efficiently. If I had thought they would have succeeded, I never would have started my company."
Aquafairy was established in mid-2006 and has been developing a fuel cell based on hydrogen. Typically an extremely reactive fuel, the company has developed a treatment that turns it into a sold form that's safe to handle but is still useful as a fuel, said Aizawa.
At Ceatec, the company has three working prototype fuel cells on show.
A pocket-size portable model, designed to fully charge a smartphone, appeared to be attracting the most interest. Producing 2.5 watts of power, it's a little lighter than a smartphone at 89 grams and measures about the same size. Through USB, it can charge most portable electronics gadgets.
A second charger is already in field trials in Japan and can deliver 200 watts of power. Weighing 7 kilograms and a little smaller than a conventional car battery, it's powered by a canister containing solid hydrogen that looks similar to the small butane canisters used in camping stoves.
Developed with Japan's New Energy and Industrial Technology Development Organization (NEDO), it has a couple of USB outputs and two conventional AC outputs. This charger is being eyed for use after disasters, like 2011's earthquake and tsunami that hit Japan.
The final charger is a long-life type designed for use in remote areas, such as mountains and forests. It provides just half a watt, but can do so for half a year meaning trips to replace batteries on things like scientific measuring equipment don't need to be made frequently.
Aquafairy is working with Japan's Rohm on the control circuitry for the chargers and to bring the products to market, but says it is also looking for partnerships with other companies and organizations.
Aizawa didn't provide a cost for the technology, but said he knows he has to deliver it at a consumer-friendly price.
"That's my job for the next year," he said.
Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is martyn_williams@idg.com