▎ 摘　　要

We performed local anodic oxidation (LAO) lithography on monolayer graphene and highly oriented pyrolytic graphite (HOPG) using atomic force microscope (AFM). Auger electron spectroscopic measurements in the oxidized area formed on the HOPG revealed that the number of oxygen atoms systematically increased with the bias voltage applied to the AFM cantilever vertical bar V-tip vertical bar, which demonstrates the tunability of the extent of oxidation with vertical bar V-tip vertical bar. By optimizing the LAO conditions, we fabricated monolayer graphene nanoconstrictions with a channel width as small as 10 nm, which is the smallest graphene nanoconstriction so far achieved by utilizing AFM lithography techniques. (C) 2015 The Japan Society of Applied Physics