February 8, 2010 – Researchers at IBM say they have once again set the mark for graphene-based transistors, setting a new mark of 100GHz cutoff frequency (100 billion cycles/sec), the highest achieved so far for any graphene device.
Graphene, the single-atom-thick layer of hexagonally-arranged carbon atoms, possesses unique and intriguing electrical, optical, mechanical, and thermal properties. "A key advantage of graphene lies in the very high speeds in which electrons propagate," which scientists hope to leverage into vastly faster transistors, stated T.C. Chen, VP of science & technology at IBM Research. (In Dec. 2008 IBM set the previous mark of 26GHz cutoff frequency.)
|SEM image of (A) a top-gated Hall bar device and (B) a top-gated field-effect transistor fabricated on the epitaxial graphene wafer. The scale bar in (B) is 2μm. (Source: Science)|
IBM also notes that the frequency performance of this graphene transistor exceeds the cutoff frequency of silicon transistors of the same gate length (~40GHz). Also, devices based on graphene obtained from natural graphite showed similar performance, indicating that performance can be obtained from graphene with different origins. (The Dec. 2008 work used graphene flakes extracted from natural graphite.)