Fast MoS2 thickness identification by transmission imaging

Determining the thickness of a few-layer 2D material is a tough task that often involves complex and time consuming measurements. Here we discuss a rapid method for determining the number of layers of molybdenum disulfide, MoS2, flakes based on microscopic transmission imaging. By analyzing the contrast of the red, blue and green channels of the flake image against the background, we show that it is possible to unequivocally determine the number of layers. The presented method is based on the light absorption properties of MoS2 and its validity is confirmed by micro-Raman measurements. The main advantage of this method against traditional methods is to quickly determine the thickness of the material in the early stages of the experimental process with low cost apparatus.