The visibility of monolayer graphene is dependent on its surrounding dielectric environment and the presence of any contamination associated with 2D layer transfer. Here, the optical contrast of residually contaminated monolayer graphene encased within a range of dielectric stacks characteristic of realistic devices is examined, highlighting the utility of optical microscopy for a graphene assessment, both during and after lithographic processing. Practically, chemical vapor deposited graphene is encapsulated in dielectric stacks of varying thicknesses of ${\mathrm{SiO}}_2$. Optical contrast is then measured and compared to predictions of a multilayer model. Experimentally measured contrast is in close agreement with simulation only when contamination is included.

中文翻译：

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介电钝化石墨烯薄膜的可见性

单层石墨烯的可见性取决于其周围的介电环境以及与2D层转移相关的任何污染的存在。在此，检查了封装在实际设备特征的介电堆栈范围内的残留污染的单层石墨烯的光学对比，突出了光学显微镜在光刻工艺过程中和之后对石墨烯评估的实用性。实际上，化学气相沉积的石墨烯被封装在不同厚度的电介质堆叠中${\mathrm{二氧化硅}}_{\mathrm{2个}}$。然后测量光学对比度，并将其与多层模型的预测值进行比较。仅当包括污染时，实验测量的对比度才与模拟非常吻合。