▎ 摘　　要

Reduction of graphene oxide at the nanoscale is an attractive approach to graphene-based electronics. Here we use a platinum-coated atomic force microscope tip to locally catalyse the reduction of insulating graphene oxide in the presence of hydrogen. Nanoribbons with widths ranging from 20 to 80nm and conductivities of >10(4)S m(-1) are successfully generated, and a field effect transistor is produced. The method involves mild operating conditions, and uses arbitrary substrates, atmospheric pressure and low temperatures (