Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Innovation is step toward digital graphene transistors

Researchers are making progress in creating digital transistors using a material called graphene, potentially sidestepping an obstacle thought to dramatically limit the material's use in computers and consumer electronics. This composite image shows the circuit schematics of a new type of graphene inverter, a critical building block of digital transistors, left, and scanning electron microscope images of the fabricated device.  (Hong-Yan Chen, Purdue University Birck Nanotechnology Center)
Researchers are making progress in creating digital transistors using a material called graphene, potentially sidestepping an obstacle thought to dramatically limit the material's use in computers and consumer electronics. This composite image shows the circuit schematics of a new type of graphene inverter, a critical building block of digital transistors, left, and scanning electron microscope images of the fabricated device.

(Hong-Yan Chen, Purdue University Birck Nanotechnology Center)

Abstract:
Complementary-Type Graphene Inverters Operating at Room Temperature

Hong-Yan Chen, Joerg Appenzeller

ECE Department and Birck Nanotechnology Center, Purdue University

Graphene has recently emerged as a promising candidate for a number of electronic applications. However, the fact that graphene is a zero-band-gap material by nature has raised many questions in terms of graphene's usefulness for digital applications. Several recent experimental studies have demonstrated graphene-based inverters, but issues remain, such as low inverter gain (0.044[1], 0.02[2]) and mismatch between input/output voltage levels [1,2]. Li et al. [3,4] reported top-gated complementary-like graphene inverters exhibiting a gain larger than 1. However, all data were obtained at 77K, and the implementation of a p-type and n-type FET was accomplished by relying on the intrinsic dependence of graphene's transfer characteristics on the supply voltage, an effect that is hardly controllable and that poses major problems for further device optimization. In this paper, focusing on inverter characteristics without attempting to build a highly scaled device, we report the first room-temperature, electrostatic-doping-controlled, complementary graphene inverter with a gain larger than one.

Innovation is step toward digital graphene transistors

West Lafayette, IN | Posted on September 6th, 2011

Researchers are making progress in creating digital transistors using a material called graphene, potentially sidestepping an obstacle thought to dramatically limit the material's use in computers and consumer electronics.

Graphene is a one-atom-thick layer of carbon that conducts electricity with little resistance or heat generation. After its discovery in 2004 - which earned a Nobel Prize in physics - it was touted as a potential replacement for silicon, possibly leading to ultrafast devices with simplified circuits that might be less expensive to manufacture.

However, graphene's luster has dulled in recent years for digital applications as researchers have discovered that it has no "band gap," a trait that is needed to switch on and off, which is critical for digital transistors.

"The fact that graphene is a zero-band-gap material by nature has raised many questions in terms of its usefulness for digital applications," said Purdue doctoral student Hong-Yan Chen.

Electrons in semiconductors like silicon exist at two energy levels, known as the valence and conduction bands. The energy gap between these two levels is called the band gap. Having the proper band gap enables transistors to turn on and off, which allows digital circuits to store information in binary code consisting of sequences of ones and zeroes.

Chen has led a team of researchers in creating a new type of graphene inverter, a critical building block of digital transistors. Other researchers have created graphene inverters, but they had to be operated at 77 degrees Kelvin, which is minus 196 Celsius (minus 320 Fahrenheit).

"If graphene could be used in digital applications, that would be really important," said Chen, who is working with Joerg Appenzeller, a professor of electrical and computer engineering and scientific director of nanoelectronics at Purdue's Birck Nanotechnology Center.

The Purdue researchers are the first to create graphene inverters that work at room temperature and have a gain larger than one, a basic requirement for digital electronics that enables transistors to amplify signals and control its switching from 0 to 1.

Findings were detailed in a paper, "Complementary-Type Graphene Inverters Operating at Room-Temperature," presented in June during the 2011 Device Research Conference in Santa Barbara, Calif.

Thus far graphene transistors have been practical only for specialized applications, such as amplifiers for cell phones and military systems. However, the new inverters represent a step toward learning how to use the material to create graphene transistors for broader digital applications that include computers and consumer electronics.

To create electronic devices, silicon is impregnated with impurities to change its semiconducting properties. Such "doping" is not easily applicable to graphene. However, the researchers have potentially solved this problem by developing "electrostatic doping," which makes it possible for graphene inverters to mimic the characteristics of silicon inverters.

Electrostatic doping is induced through the electric field between metal gates, which are located 40 nanometers away from graphene channels. The doping can be altered by varying the voltage, enabling researchers to test specific doping levels.

"This will allow us to find the sweet spot for operating the device," Chen said.

Further work will be needed to integrate the prototype into a working graphene circuit for digital applications.

The research is based at the Birck Nanotechnology Center in Purdue's Discovery Park.

####

For more information, please click here

Contacts:
Writer:
Emil Venere
765-494-4709


Sources:
Joerg Appenzeller
765-494-1076


Hong-Yan Chen

Copyright © Purdue University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

New method allows for greater variation in band gap tunability: The method can change a material's electronic band gap by up to 200 percent January 31st, 2015

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Everything You Need To Know About Nanopesticides January 30th, 2015

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

Graphene

Discovery Channel taps Angstron Materials for segment featuring graphene advances January 29th, 2015

Creating new materials with quantum effects for electronics January 29th, 2015

Graphenea sales more than double in 2014 January 29th, 2015

Researchers Make Magnetic Graphene: UC Riverside research could lead to new multi-functional electronic devices January 27th, 2015

Chip Technology

Creating new materials with quantum effects for electronics January 29th, 2015

Advantest to Exhibit at SEMICON Korea in Seoul, South Korea February 4-6 Showcasing Broad Portfolio of Semiconductor Products, Technologies and Solutions January 29th, 2015

Researchers Make Magnetic Graphene: UC Riverside research could lead to new multi-functional electronic devices January 27th, 2015

Nanometrics to Present at the Stifel 2015 Technology, Internet and Media Conference January 27th, 2015

Nanoelectronics

Electronic circuits with reconfigurable pathways closer to reality January 26th, 2015

Rice-sized laser, powered one electron at a time, bodes well for quantum computing January 15th, 2015

Rapid journey through a crystal lattice: Researchers measure how fast electrons move through single atomic layers January 14th, 2015

A new step towards using graphene in electronic applications January 14th, 2015

Discoveries

New method allows for greater variation in band gap tunability: The method can change a material's electronic band gap by up to 200 percent January 31st, 2015

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Everything You Need To Know About Nanopesticides January 30th, 2015

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

Announcements

New method allows for greater variation in band gap tunability: The method can change a material's electronic band gap by up to 200 percent January 31st, 2015

Evidence mounts for quantum criticality theory: Findings bolster theory that quantum fluctuations drive strange electronic phenomena January 30th, 2015

Everything You Need To Know About Nanopesticides January 30th, 2015

DNA nanoswitches reveal how life's molecules connect: An accessible new way to study molecular interactions could lower cost and time associated with discovering new drugs January 30th, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE