标题：Intriguing electronic properties of two-dimensional MoS2/TM2CO2 (TM = Ti, Zr, or Hf) hetero-bilayers: type-II semiconductors with tunable band gaps
作者：Li, Xinru;Dai, Ying;Ma, Yandong;Liu, Qunqun;Huang, Baibiao
作者机构：Shandong Univ, Sch Phys, State Key Lab Crystal Mat, Jinan 250100, Peoples R China;Shandong Univ, Sch Phys, State Key Lab Crystal
关键词：MXene monolayer;transition metal disulfide monolayer;density functional theory;two dimensional heterostructure
摘要：Two-dimensional (2D) transition metal compound (TMC) monolayers, as well as their van der Waals heterostructures with unique properties, are fundamentally and technologically intriguing. Here, heterostructures consisting of a MoS2 monolayer and TM2CO2 (TM = Ti, Zr or Hf) monolayers are systematically researched by means of the density functional theory (DFT). Different from semiconductor/metal contacts, MoS2 and TM2CO2 monolayers are all semiconductors with band gaps ranging from 0.25-1.67 eV. According to rigorous screening of stacking patterns, MoS2/Zr2CO2 is shown to be an indirect type-II semiconductor with the maximum valence and minimum conduction bands spatially separated on opposite monolayers. Simultaneously, the interface charges transfer from Zr2CO2 to MoS2 results in a built-in field that separates the electrons and holes efficiently. Also, the smaller effective masses of electrons and the holes of band edges indicate the higher carrier mobility. Moreover, strain regulation can make the hetero-bilayer\'s character a semiconductor-semimetal-metal transition. The physical insights pave the way for the good performance of MoS2/TM2CO2 in next-generation electronic devices and photocatalysts.