Physics Department, University of Arizona , Tucson, Arizona 85721, United States.
Nano Lett. 2015 Mar 11;15(3):1925-9. doi: 10.1021/nl5047736. Epub 2015 Feb 12.
Semiconducting transition metal dichalchogenides (TMDs) are a family of van der Waals bonded materials that have recently received interest as alternative substrates to hexagonal boron nitride (hBN) for graphene, as well as for components in novel graphene-based device heterostructures. We elucidate the local structural and electronic properties of graphene on TMD heterostructures through scanning tunneling microscopy and spectroscopy measurements. We find that crystalline defects intrinsic to TMDs induce substantial electronic scattering and charge carrier density fluctuations in the graphene. These signatures of local disorder explain the significant degradation of graphene device mobilities using TMD substrates, particularly compared to similar graphene on hBN devices.
半导体过渡金属二卤族化合物（TMDs）是一类范德瓦尔斯结合材料，最近因其作为六方氮化硼（hBN）替代衬底用于石墨烯，以及用于新型基于石墨烯的器件异质结构中的组件而受到关注。我们通过扫描隧道显微镜和光谱测量阐明了 TMD 异质结构上石墨烯的局部结构和电子特性。我们发现 TMD 固有的晶体缺陷会在石墨烯中引起大量的电子散射和载流子密度波动。这些局部无序的特征解释了使用 TMD 衬底时石墨烯器件迁移率的显著降低，尤其是与类似的石墨烯在 hBN 器件中的迁移率相比。
