Oxygen adsorption in graphene can be controlled using a field-effect transistor

Graphene can adsorb oxygen onto its surface (which changes graphene's electronic transport properties). This can be useful for Spintronics devices, but the adsorption is difficult to control. Researchers from the Tokyo Institute of Technology developed a way to control the adsorption of oxygen by applying an electric field to a Graphene-based field-effect transistor (FET).

The density of carriers (electrons and holes) in the FET can be tuned by applying an electric field to the gate of the device and, when oxygen molecules then adsorb onto the device, the conductivity of the FET changes.

Read the full story Posted: Aug 20,2011

Scientist predicts that Graphene will skip FET and jump straight to quantum devices

Georgia Tech Professor Walt de Heer predicts that Graphene will not follow the model of using standard field-effect transistors, but will pursue devices that use ballistic conductors and quantum interference. The Professor's research team hopes to show a basic quantum interference switch within a year.

Taking advantage of the wave properties will allow electrons to be manipulated with techniques similar to optical control, for instance switching may be carried out using interference - separating beams of electrons and then recombining them in or out of phase to switch the signal.

Read the full story Posted: Mar 24,2011

SiO2 can be used to improve a Graphene based FET, paves the way towards Graphene nonvolatile memory

Researchers from the A*STAR Institute of Materials Research and Engineering and the National University of Singapore have developed an improved design for a Graphene based field-effect transistor (FET). The new device includes an additional silicon dioxide (SiO2) dielectric gate below the graphene layer. This allows for simplified bit writing by providing an additional background source of charge carriers.

The new device can lead the way towards ;grapheneferroelectric FETs to be used for nonvolatile memory. The researchers say that the new design achieved impressive practical results - symmetrical bit writing with a resistance ratio between the two resistance states of over 500% and reproducible nonvolatile switching over 100,000 cycles.

Read the full story Posted: Feb 16,2011

IBM opened a bandgap for Graphene FETs, commercialization is closer than ever

IBM Researchers has opened a bandgap for graphene field-effect transistors (FET) that could someday rival complementary metal oxide semiconductor. This is one of the last roadblocks to commercialization of Graphene-based technology, according to IBM.

Graphene has a higher carrier mobility than Silicon, but lacks a band gap, which has kept the on-off ratio of graphene transistors dismally low—usually less than 10 compared to hundreds for silicon. Now IBM says that they have managed to create a tunable electrical bandgap (up to 130meV) for their bi-layer graphene FETs. And larger bandgaps are possible, too.

Read the full story Posted: Jan 28,2010