Facile and reliable determination of multilayer graphene thickness using optical microscopy

Abstract

Optical transmittance of exfoliated multilayer graphene (MLG) was investigated and cross-referenced with a standard monolayer sample. Plots of grayscale values against position on the images were found to have step-like profiles. Step heights were extracted from the profiles and found to have peak points. The peaks occur at approximately 80 layers region. These findings occur due to interlayer interactions within the samples, with the 80 layers being the transition from MLG to the bulk graphite. Our experimental results show optical transmittance of %3.97 , %2.95

%2.93 and %3.91 for single layer, bilayer, trilayer and tetralayer respectively. The observed exponential decrease in transmittance with the number of graphene layers has been attributed to the variations in optical absorption of the incident light by the MLG samples.