Determination of the Number of Graphene Layers on Different Substrates by Optical Microscopy Technique

We present a method, based on transmission or reflection optical microscopy, to determine the number of graphene monolayers deposited on various substrates. To demonstrate the procedure, we synthesize graphene samples and deposit them on various substrates with the micromechanical cleavage technique. Our procedure initially relies on more classical approaches such as atomic force microscopy (AFM) and Raman to calibrate the equipment. After calibration, however, optical microscopy by itself is sufficient to characterize other samples, deposited on any substrate.