Optical microscopy–based thickness estimation in thin GaSe flakes

null null We have implemented three different optical methods to quantitatively assess the thickness of thin GaSe flakes transferred on both transparent substrates, like Gel-Film, and SiO2/Si substrates. We show how their apparent color can be an efficient way to make a quick, rough estimation of the thickness of the flakes. This method is more effective for SiO2/Si substrates as the thickness-dependent color change is more pronounced on these...