▎ 摘　　要

A He+ ion beam is used to induce electronic localization, on a single graphene layer exfoliated on an ultra-flat sapphire substrate, based on crystalline defects and with a lateral irradiation precision of 1 nm. Inducing a 1% carbon defect density by step by step irradiation of a 100-nm-wide band on the supported graphene increases its electrical resistance from 0.90 to 133 k Omega. The resistance build-up was monitored in situ and in real time by measuring the I(t) current intensity through the graphene monolayer flake during its irradiation. The whole process takes place on an ultra-polished sapphire surface used to retain the planarity of the graphene. We propose that local heating of the graphene by irradiation promotes the migration of the created atomic carbon defects to the edge of the flake. This inherently moderates the increase of resistance with time during He+ irradiation due to the gradual re-opening of low-voltage graphene ballistic channels. (C) 2019 The Japan Society of Applied Physics