Optical Study of Few-Layer Graphene Treated by Oxygen Plasma

Oxygen plasma treatment is often used to clean the surface or etch graphene for functional structures. Some unique properties such as photoluminescence (PL), energy bandgap engineering, and so on are presented in single-layer graphene (SLG). Compared with SLG, few-layer graphene (FLG) has higher luminescence intensity, slower decay rate, and better controllability. It is more universal in the application of new optoelectronic devices and transparent electrodes. So, a systematic study is provided to analyze the mechanism between chemical vapor deposition of few-layer graphene and oxygen plasma process based on the optical characterization method. Surface morphology, structural defects, resistance change, chemical state, and PL are traced and investigated under different oxygen plasma treatment times. The C-O and C(sic)O bonds on the surface of the FLG appear to increase and then decrease with oxygen plasma etching based on X-ray photoelectron spectroscopy (XPS) characterization. A linear square resistance change is presented from 1.4 to 4.8 k omega sq(-1). Besides that, an obvious redshift-blueshift change is produced in fluorescence characteristic spectra. Herein, comprehensive research on the influencing mechanism of graphene and oxygen treatment is exhibited, which provides the potential to construct optoelectronic devices.