▎ 摘　　要

We propose a new approach to open the bandgap of graphene by fabricating a hexagonal nanoribbon network. We have successfully fabricated hexagonal graphene network pattern (GNP) out of exfoliated monolayer graphene by electron beam lithography. Transport characteristics were investigated using a top-gated Hall-bar device. The electron mobility of GNP with 40 nm ribbon width, d, was 452 cm(2) V-1 s(-1) at 90 K and on/off ratio of top-gated field-effect transistors (FET) exceeded 8.6 at room temperature, which shows significant improvement compared with on/off ratio of 2 in control sample without network pattern. (C) 2011 The Japan Society of Applied Physics