Scientists at the University of Illinois at Urbana-Champaign have developed the fastest transistor (a typical computer processor contains millions of these). Working at the blinding speed of 604GHz, the new device was built from compounds called Indium Phosphide and Indium Gallium Arsenide that were designed to reduce data-transit time and improve density. The same group established an earlier record in 2003, when they made a transistor work at 509GHz (by breaking their own records of 452GHz and 382GHz).

Light emitting transistor (Courtesy: UIUC)The research was funded by the U.S. military through a $5.9 million DARPA grant. The results were published by Milton Feng and his student Walid Hafez in the journal Applied Physics Letters.
This new transistor paves the way to the creation of tera-hertz (1000+ GHz) devices. The researchers employed a technique known as Pseudomorphic grading, in which selective doping of the base, collector and emitter regions of the transistor results in a lower band-gap, and therefore, higher speed.
Once wired by the thousands into circuits, this faster transistor could improve the quality and battery life of high-frequency electronics like cell phones. This work can also lead to faster and more energy efficient computers and communication networks: the same group created the world's first light emitting transistor in 2003, which when combined with this transistor, can make high-speed (Tera-Hertz) fiber-optic communications possible.