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 substrates than on transparent substrates. On the other hand, for transparent substrates, the transmittance of the flakes in the blue region of the visible spectrum can be used to estimate the thickness. We find that the transmittance of flakes in the blue part of the spectrum decreases at a rate of 1.2%/nm. On SiO₂/Si, the thickness of the flakes can be accurately determined by fitting optical contrast spectra to a Fresnel law-based model. Finally, we also show how the quantitative analysis of transmission mode optical microscopy images can be a powerful method to quickly probe the environmental degradation of GaSe flakes exposed to aging conditions.

我们已经实施了三种不同的光学方法，以定量评估在两个透明基板（如Gel-Film和SiO ₂ / Si基板）上转移的GaSe薄片的厚度。我们展示了它们的表观颜色如何成为快速，粗略估计薄片厚度的有效方法。该方法对SiO ₂ / Si基板更有效，因为与透明基板相比，这些基板上与厚度相关的颜色变化更为明显。另一方面，对于透明衬底，薄片在可见光谱的蓝色区域中的透射率可用于估计厚度。我们发现，薄片在光谱的蓝色部分的透射率以1.2％/ nm的速率降低。在SiO _2上/ Si，可以通过将光学对比光谱拟合到基于菲涅耳定律的模型来准确确定薄片的厚度。最后，我们还展示了透射模式光学显微镜图像的定量分析如何成为快速检测暴露于老化条件下的GaSe薄片在环境中降解的有效方法。