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Published May 28, 2013 | Supplemental Material + Published
Journal Article Open

Graphene field effect transistor without an energy gap


Graphene is a room temperature ballistic electron conductor and also a very good thermal conductor. Thus, it has been regarded as an ideal material for postsilicon electronic applications. A major complication is that the relativistic massless electrons in pristine graphene exhibit unimpeded Klein tunneling penetration through gate potential barriers. Thus, previous efforts to realize a field effect transistor for logic applications have assumed that introduction of a band gap in graphene is a prerequisite. Unfortunately, extrinsic treatments designed to open a band gap seriously degrade device quality, yielding very low mobility and uncontrolled on/off current ratios. To solve this dilemma, we propose a gating mechanism that leads to a hundredfold enhancement in on/off transmittance ratio for normally incident electrons without any band gap engineering. Thus, our saw-shaped geometry gate potential (in place of the conventional bar-shaped geometry) leads to switching to an off state while retaining the ultrahigh electron mobility in the on state. In particular, we report that an on/off transmittance ratio of 130 is achievable for a sawtooth gate with a gate length of 80 nm. Our switching mechanism demonstrates that intrinsic graphene can be used in designing logic devices without serious alteration of the conventional field effect transistor architecture. This suggests a new variable for the optimization of the graphene-based device—geometry of the gate electrode.

Additional Information

© 2013 National Academy of Sciences. Contributed by William A. Goddard III, March 22, 2013 (sent for review November 5, 2012). Published online before print May 13, 2013. This work was supported by Department of Energy Light-Material Interactions in Energy Conversion–Energy Frontier Research Center Grant DE-SC0001293 (to M.S.J. and H.A.A.), the National Science Foundation (CMMI-1120890, to W.A.G.), and the Functional Engineered Nano Architectonics via the Microelectronics Advanced Research Corporation with Prime Award 2009-NT-2048 at University of California, Los Angeles (to W.A.G.). H.K. and W.A.G. also acknowledge support from the World Class University programs through National Research Foundation (NRF) of Korea funded by Ministry of Education, Science and Technology (MEST) Grant R31- 2008-000-10055-0. H.K. also is grateful for the support of the Nanomaterial Technology Development Program through the NRF of Korea funded by MEST Grant 2012M3A7B4049807. Y.-W.S. was in part supported by MEST (Grant QMMRC R11-2008-053-01002-0 and Center for Advanced Soft Electronics 2011-0031640). Author contributions: M.S.J., H.K., Y.-W.S., H.A.A., and W.A.G. designed research; M.S.J., H.K., and W.A.G. performed research; M.S.J., H.K., Y.-W.S., H.A.A., and W.A.G. analyzed data; and M.S.J., H.K., Y.-W.S., H.A.A., and W.A.G. wrote the paper.

Attached Files

Published - PNAS-2013-Jang-8786-9.pdf

Supplemental Material - pnas.201305416SI.pdf


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August 22, 2023
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