IBM believe they have achieved the highest cut-off frequency so far for any graphene device of 100 billion cycles/second (100 GigaHertz).
Due to its exceptional electronic properties, graphene is considered as a leading material for next generation electronic devices in the multibillion dollar semiconductor industry. It has the potential to enable terahertz computing at processor speeds 100 to 1000 times faster than silicon.
"A key advantage of graphene lies in the very high speeds in which electrons propagate, which is essential for achieving high-speed, high-performance next generation transistors," said Dr. T.C. Chen, vice president, Science and Technology, IBM Research.
Graphene is a single atom-thick layer of carbon atoms bonded in a hexagonal honeycomb-like arrangement. This two-dimensional form of carbon has unique electrical, optical, mechanical and thermal properties.
IBM researchers reported that, "The high frequency record was achieved using wafer-scale, epitaxially grown graphene using processing technology compatible to that used in advanced silicon device fabrication."
"Uniform and high-quality graphene wafers were synthesized by thermal decomposition of a silicon carbide (SiC) substrate. The graphene transistor itself utilized a metal top-gate architecture and a novel gate insulator stack involving a polymer and a high dielectric constant oxide. The gate length was modest, 240 nanometers, leaving plenty of space for further optimization of its performance by scaling down the gate length."
They also noted that, "The frequency performance of the graphene device already exceeds the cut-off frequency of state-of-the-art silicon transistors of the same gate length (~ 40 GigaHertz). Similar performance was obtained from devices based on graphene obtained from natural graphite, proving that high performance can be obtained from graphene of different origins."
This could aid the Carbon Electronics for RF Applications (CERA) programme. They are looking at developing next generation devices using graphene-based RF electronics that will lead to ultra-high-speed, ultra-low-noise, ultra-low power RF circuits. The impact on communications, electronic warfare, radar, and many other key DoD systems will be significant.
Graphene is being studied worldwide for electronics, displays, solar cells, sensors, and hydrogen storage.
Texan company, Graphene Energy have shown storage abilities similar to those of ultracapacitors already on the market, and they believe graphene's ultra thin structure will allow for sheets of the material to be stacked to increase energy storage and possibly double the current capacity of ultracapacitors. This would allow ultracapacitors to expand into solar energy industries where energy storage is a challenge when the sun isn't shining.
Over a year ago, the team demonstrated graphene transistors with a cut-off frequency of 26 GigaHertz using graphene flakes extracted from natural graphite.
For more attend Printed Electronics Europe 2010.