Characterization of graphene based field effect transistors using nano probing microscopy

We have investigated the effects of UV-ozone treatment at both high and low exposure level on graphene-based FETs (G-FETs) by analyzing and comparing the I-V characteristic of the device before and after the exposure. The former induced significant structural damage or defects on the graphene layer, while the latter did not. The conductivity of G-FETs decreased after both exposure, and the characteristics of post-exposure G-FETs were stable even after 24 hours had elapsed, which indicates that the effect on the graphene layer was confirmed to be permanent. The characterizations of G-FETs were conducted using scanning electron microscopy (SEM) equipped with electrical probes (nano probing microscopy). The results indicate that the electron beam irradiation for SEM did not induce damages in the graphene and the nano probing microscopy is applicable to the researches of G-FETs.