Abstract Optical imaging is a promising method to identify and locate 2D materials efficiently and non-invasively. By putting a 2D material on a substrate, the nanolayer will add to an optical path and create a contrast to the case when the nanolayer is absent. This optical contrast imaging can be used to identify the 2D material and its number of layers. To make the optical imaging process in the laboratories an effective tool, Fresnel Law as a model was used to simulate the optical imaging results of 2D materials (graphene, MoS2 and MoSe2) on top of different thickness of SiO2 and Si wafer in the present investigation. The results provide the details of the optimal conditions (optimal light wavelength and optimal SiO2 thickness) to identify and locate single to few 2D nanolayers, which can be used directly in laboratories. The optical contrasts of 1–5 layers of molybdenum disulfide (MoS2) and molybdenum diselenide (MoSe2) were simulated. To the best of our knowledge, it is the first time that the optical contrast results of MoSe2 have been reported. In particular, this work highlights the sensitivity of the model on the accuracy of the refractive indices used. It is demonstrated that through computational modeling that optical contrast can allow effective determination of number of layers in few layer 2D materials.

中文翻译：

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通过光学对比度模拟检测 MoS2 和 MoSe2

摘要 光学成像是一种有效且非侵入性地识别和定位二维材料的有前途的方法。通过将 2D 材料放在基板上，纳米层将增加光路并与没有纳米层时的情况形成对比。这种光学对比成像可用于识别二维材料及其层数。为了使实验室中的光学成像过程成为一种有效的工具，本研究以菲涅耳定律为模型，模拟了在不同厚度的 SiO2 和 Si 晶片上的二维材料（石墨烯、MoS2 和 MoSe2）的光学成像结果. 结果提供了最佳条件（最佳光波长和最佳 SiO2 厚度）的详细信息，以识别和定位单个到几个 2D 纳米层，可直接在实验室中使用。模拟了 1-5 层二硫化钼 (MoS2) 和二硒化钼 (MoSe2) 的光学对比。据我们所知，这是第一次报道 MoSe2 的光学对比度结果。特别是，这项工作突出了模型对所用折射率准确性的敏感性。结果表明，通过计算建模，光学对比度可以有效确定少数二维材料中的层数。