Navigation Links
Carbon nanoribbons could make smaller, speedier computer chips

Stanford chemists have developed a new way to make transistors out of carbon nanoribbons. The devices could someday be integrated into high-performance computer chips to increase their speed and generate less heat, which can damage today's silicon-based chips when transistors are packed together tightly.

For the first time, a research team led by Hongjie Dai, the J. G. Jackson and C. J. Wood Professor of Chemistry, has made transistors called "field-effect transistors"-a critical component of computer chips-with graphene that can operate at room temperature. Graphene is a form of carbon derived from graphite. Other graphene transistors, made with wider nanoribbons or thin films, require much lower temperatures.

"For graphene transistors, previous demonstrations of field-effect transistors were all done at liquid helium temperature, which is 4 Kelvin [-452 Fahrenheit]," said Dai, the lead investigator. His group's work is described in a paper published online in the May 23 issue of the journal Physical Review Letters.

The Dai group succeeded in making graphene nanoribbons less than 10 nanometers wide, which allows them to operate at higher temperatures. "People had not been able to make graphene nanoribbons narrow enough to allow the transistors to work at higher temperatures until now," Dai said. Using a chemical process developed by his group and described in a paper in the Feb. 29 issue of Science, the researchers have made nanoribbons, strips of carbon 50,000-times thinner than a human hair, that are smoother and narrower than nanoribbons made through other techniques.

Field-effect transistors are the key elements of computer chips, acting as data carriers from one place to another. They are composed of a semiconductor channel sandwiched between two metal electrodes. In the presence of an electric field, a charged metal plate can draw positive and negative charges in and out of the semiconductor. This allows the electric current to either pass through or be blocked, which in turn controls how the devices can be switched on and off, thereby regulating the flow of data.

Researchers predict that silicon chips will reach their maximum shrinking point within the next decade. This has prompted a search for materials to replace silicon as transistors continue to shrink in accordance with Moore's Law, which predicts that the number of transistors on a chip will double every two years. Graphene is one of the materials being considered.

David Goldhaber-Gordon, an assistant professor of physics at Stanford, proposed that graphene could supplement but not replace silicon, helping meet the demand for ever-smaller transistors for faster processing. "People need to realize this is not a promise; this is exploration, and we'll have a high payoff if this is successful," he said.

Dai said graphene could be a useful material for future electronics but does not think it will replace silicon anytime soon. "I would rather say this is motivation at the moment rather than proven fact," he said.

Although researchers, including those in his own group, have shown that carbon nanotubes outperform silicon in speed by a factor of two, the problem is that not all of the tubes, which can have 1-nanometer diameters, are semiconducting, Dai said. "Depending on their structure, some carbon nanotubes are born metallic, and some are born semiconducting," he said. "Metallic nanotubes can never switch off and act like electrical shorts for the device, which is a problem."

On the other hand, Dai's team demonstrated that all of their narrow graphene nanoribbons made from their novel chemical technique are semiconductors. "This is why structure at the atomic scale-in this case, width and edges-matters," he said.


Contact: Louis Bergeron
Stanford University

Related biology technology :

1. Awareness of Genzymes Renvela(R) (Sevelamer Carbonate) is High, Although Uptake of this New Phosphate Binding Agent has Been Slower than Nephrologists and Renal Dietitians Initially Expected
2. Breakthrough in nanotechnology by uncovering conductive property of carbon-based molecules
3. Carbon nanotube measurements: latest in NIST how-to series
4. Carbon nanotubes made into conductive, flexible stained glass
5. The future of computing -- carbon nanotubes and superconductors to replace the silicon chip
6. Carbon nanotubes outperform copper nanowires as interconnects
7. Mission critical for carbon management
8. National Association of Emergency Medical Technicians (NAEMT) Supports Prehospital Screening for Carbon Monoxide in the Blood
9. Carbon offset warning from international team of scientists
10. International Association of Fire Fighters (IAFF) Advocates Screening Fire Fighters for Carbon Monoxide Poisoning Using Pulse CO-Oximetry
11. ADM, MGSC and ISGS Announce Carbon Sequestration Project
Post Your Comments:
(Date:11/30/2015)... Jose, CA (PRWEB) , ... ... ... Content Intelligence Company, today announced tighter software integration with MarkLogic, the Enterprise ... where organizations maximize information to drive change. , Smartlogic’s Content Intelligence capabilities ...
(Date:11/27/2015)... ... November 27, 2015 , ... Pittcon is pleased to announce ... offered in symposia, oral sessions, workshops, awards, and posters. The core of ... applications such as, but not limited to, biotechnology, biomedical, drug discovery, environmental, food ...
(Date:11/25/2015)... 26, 2015 --> ... 2016 - 2020 report analyzes that automating biobanking ... quality in long-term samples, minimizing manual errors, improving ... minimizes manual errors such as mislabeling or inaccurate ... it plays a vital role in blood fractionation, ...
(Date:11/25/2015)... Mass. , Nov. 25, 2015 Harvard ... biotechnology company developing bioengineered organ implants for life-threatening conditions, ... present at the LD Micro "Main Event" investor conference ... The presentation will be webcast live and posted for ... be available at the conference for one-on-one meetings on ...
Breaking Biology Technology:
(Date:11/18/2015)... ALBANY, New York , November 18, 2015 /PRNewswire/ ... Transparency Market Research has published a new market report ... Share, Growth, Trends, and Forecast, 2015 - 2021. According to ... bn in 2014 and is anticipated to reach US$29.1 ... 2015 to 2021. North America ...
(Date:11/17/2015)... November 17, 2015 Paris ... 2015.  --> Paris , qui ... DERMALOG, le leader de l,innovation biométrique, a inventé ... passeports et empreintes sur la même surface de balayage. ... et l,autre pour les empreintes digitales. Désormais, un seul ...
(Date:11/17/2015)... 17, 2015 Pressure BioSciences, Inc. (OTCQB: PBIO) ... and sale of broadly enabling, pressure cycling technology ("PCT")-based ... today announced it has received gross proceeds of $745,000 ... Placement (the "Offering"), increasing the total amount raised to ... additional closings are expected in the near future. ...
Breaking Biology News(10 mins):