Ambipolar behavior in epitaxial graphene-based field-effect transistors on Si substrate

Roman Olac-Vaw, Hyun Chul Kang, Hiromi Karasawa, Yu Miyamoto, Hiroyuki Handa, Hirokazu Fukidome, Tetsuya Suemitsu, Maki Suemitsu, Taiichi Otsuji

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


In this research, ambipolar behavior, which is one of graphene's unique characteristics, is studied for the epitaxial graphene formed on 3C-SiC grown on a Si substrate. The graphene channel is believed to be unintentionally p-type-doped at Dirac-point voltages of approximately +0.11 to +0.12 V. However, as drain voltage negatively increases, Dirac point voltage shifts. The drain current in the p-channel mode of operation saturates at a lower level than that in the n-channel mode of operation. These behaviors are caused by asymmetric carrier transport throughout channelsubstrate heterojunctions (i.e., graphene, thin n-type SiC layer, and p-type Si substrate) and source/drain Schottky metal contacts. The interface between the p-type Si substrate and n-type SiC has a significant effect on transport in graphene channels. The results may be helpful for understanding transport in the device and for suppressing ambipolar operation, leading to a unipolar FET operation.

Original languageEnglish
Pages (from-to)06GG011-06GG015
JournalJapanese journal of applied physics
Issue number6 PART 2
Publication statusPublished - 2010 Jun 1

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)


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