▎ 摘　　要

Metal-graphene contact in graphene field-effect transistors (GFETs) causes ambipolar characteristics unsuitable for complementary logic circuits. We devised source and drain structures for suppressing these ambipolar characteristics in GFETs. The calculation results demonstrate the effectiveness of the devised structures. Similar structures could be applied to FETs with channels made by narrow-gap materials. (C) 2009 The Japan Society of Applied Physics