Electrical, Electronic and Optical Characterization of Multilayer Graphene Films for Transparent Electrodes

The electrical, electronic and optical properties of multilayer graphene (MLG) films have been investigated systematically using a 4-point probe method, ultraviolet photoelectron spectroscopy, and ultraviolet/visible spectrometer. Monolayer graphene and MLG (2, 3, 4 and 5 layers) films were prepared on glass and SiO2 substrates using a chemical vapor deposition and multi-transfer process. Raman spectroscopy was used to evaluate the quality of MLG films. Sheet resistance, work function and transmittance were measured systematically for each monolayer graphene and MLG films. In addition, surface treatment with HNO3 was performed to reduce the sheet resistance of the MLG films. The sheet resistance was reduced to 198 Ω/square after the treatment without any significant change in the MLG film quality. These results will provide useful information for the optoelectronic devices based on MLG films.