Spectroscopic ellipsometry of few-layer graphene

The optical properties of few-layer graphene (FLG) films were measured in the ultraviolet and visible spectrum using a spectroscopic ellipsometer equipped with a 50-mu m nominal microspot size. The FLG thickness was found by atomic force microscopy. Measurements revealed that the microspot is larger than the FLG flake. The ellipsometric data was interpreted using the island-film model. Comparison with graphite and recently published graphene data showed reasonable agreement, but with some features that could not be explained. The error margin for the optical constants was estimated to be +/- 10%. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3598162]