With precision control of its bandgap over a wide range, plus independent manipulation of its electronic states through electrical doping, dual-gated bilayer graphene becomes a remarkably flexible tool for nanoscale electronic devices.
Wang emphasizes that these first experiments are only the beginning. "The electrical performance of our demonstration device is still limited, and there are many routes to improvement, for example through extra measures to purify the substrate."
Nevertheless, he says, "We've demonstrated that we can arbitrarily change the bandgap in bilayer graphene from zero to 250 milli-electron volts at room temperature, which is remarkable in itself and shows the potential of bilayer graphene for nanoelectronics. This is a narrower bandgap than common semiconductors like silicon or gallium arsenide, and it could enable new kinds of optoelectronic devices for generating, amplifying, and detecting infrared light."
"Direct observation of a widely tunable bandgap in bilayer graphene," by Yuanbo Zhang, Tsung-Ta Tang, Caglar Girit, Zhao Hao, Michael C. Martin, Alex Zettl, Michael F. Crommie, Y. Ron Shen, and Feng Wang, appears in the June 11, 2009 issue of Nature. Zhang, Tang, and Girit are members of UC Berkeley's Department of Physics, in the groups of Professors Crommie, Shen, and Zettl respectively; Zettl, Crommie, and Shen are also members of Berkeley Lab's Materials Sciences Division.
|Contact: Paul Preuss|
DOE/Lawrence Berkeley National Laboratory