Controlled generation of atomic vacancies in chemical vapor deposited graphene by microwave oxygen plasma

The introduction of atomic-scale defects in a controllable manner and the understanding of their effect on the characteristics of graphene are essential to develop many applications based on this two-dimensional material. Here, we investigate the use of microwave-induced oxygen plasma towards the generation of small-sized atomic vacancies (holes) in graphene grown by chemical vapor deposition. Scanning tunneling microscopy revealed that tunable vacancy densities in the 103-105 μm−2 range could be attained with proper plasma parameters. Transport measurements and Raman spectroscopy revealed p-type doping and a decrease in charge carrier mobility for the vacancy-decorated samples. This plasma-modified graphene could find use in, e.g., gas or liquid separation, or molecular sensing.