Probing the electron states and metal-insulator transition mechanisms in molybdenum disulphide vertical heterostructures
Probing the electron states and metal-insulator transition mechanisms in molybdenum disulphide vertical heterostructures
复制标题
DOI：
10.1038/ncomms7088
复制
发表时间：
2015-01-01
影响因子：
16.6
通讯作者：
Wang, Ning
中科院分区：
文献类型：
--
作者：
Chen, Xiaolong;Wu, Zefei;Wang, Ning
金属-绝缘体转变是原子级薄二硫化钼的显著电学性质之一。虽然电子-电子相互作用理论已被用于模拟二硫化钼中的金属-绝缘体转变，但基本机制和详细的转变过程仍然在很大程度上未被探索。在这里，我们表明，从原子级薄二硫化钼的垂直金属-绝缘体-半导体异质结构是理想的电容器结构，用于探测电子状态。垂直配置提供了额外的优势，消除了在带尾处的大阻抗的影响，并允许在宽的激发频率和温度范围内观察二硫化钼表面附近的完全激发的电子状态。通过结合电容和输运测量，我们观察到了一个双折射型金属-绝缘体的转变，驱动的电子态密度不均匀性，在单层和多层二硫化钼。此外，还讨论了二硫化钼薄膜的价带及其本征性质。
The metal-insulator transition is one of the remarkable electrical properties of atomically thin molybdenum disulphide. Although the theory of electron-electron interactions has been used in modelling the metal-insulator transition in molybdenum disulphide, the underlying mechanism and detailed transition process still remain largely unexplored. Here we demonstrate that the vertical metal-insulator-semiconductor heterostructures built from atomically thin molybdenum disulphide are ideal capacitor structures for probing the electron states. The vertical configuration offers the added advantage of eliminating the influence of large impedance at the band tails and allows the observation of fully excited electron states near the surface of molybdenum disulphide over a wide excitation frequency and temperature range. By combining capacitance and transport measurements, we have observed a percolation-type metal-insulator transition, driven by density inhomogeneities of electron states, in monolayer and multilayer molybdenum disulphide. In addition, the valence band of thin molybdenum disulphide layers and their intrinsic properties are accessed.