▎ 摘　　要

A potential difference between the two layers of bilayer graphene caused by charge doping and/or an applied gate field can open a bandgap. In this paper, bandgap and charge controllability in graphene field-effect transistors (GFETs) with doped bilayer graphene channels is clarified by solving a one-dimensional Poisson's equation, including electron and hole concentrations derived from a tight-binding Hamiltonian. The calculations show that a high doping concentration of 10(13) cm(-2) is required to produce a bandgap of 0.3 eV and that this degrades the charge controllability in GFETs. (C) 2009 The Japan Society of Applied Physics