HOUSTON, TXRice University research into the wide-ranging capabilities of graphene could lead to circuit applications that are more compact and versatile with silicon-based technologies. Triple-mode, singletransistor amplifiers based on graphenethe one-atom-thick form of carbon whose discoverers recently won a Nobel Prize could become key components in future electronic circuits. By combining the three modes, for example, the Rice-Riverside team demonstrated such common signaling schemes as phase and frequency shift keying for wireless and audio applications.

Graphene is strong, nearly transparent, and conducts electricity very well. Another key property is its ambipolaritygraphene's ability to switch between using positive and negative carriers depending on the input signal. A three-terminal, single-transistor amplifier made of graphene can be changed during operation to any of three modes at any time using carriers that are positive, negative, or both. In doing so, it provides opportunities that are not possible with traditional single-transistor architectures, states Kartik Mohanram, an Assistant Professor of Electrical and Computer Engineering at Rice. He collaborated on the research with Alexander Balandin, a Professor of Electrical Engineering at the University of California, Riverside, and students Xuebei Yang (Rice) and Guanxiong Liu (Riverside).

The research demonstrated that a single graphene transistor could potentially replace many transistors in a typical IC. Graphene's superior material properties and compatibility with silicon-based manufacturing should allow for the integration of such circuits in the future. This work is supported by the National Science Foundation and the DARPA-Semiconductor Research Corporation's Focus Center Research Program.

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