关键词: 光电探测器, 单层2H-MoTe₂, 光电效应, 能带结构, 态密度, 第一性原理

Abstract: The band gap of the material is an important factor affecting the detection ranges of the photodetector. The monolayer 2H-MoTe₂ has attracted a wide range of research interests due to its suitable band gap. In this paper, based on the non-equilibrium Green's function-density functional theory, using first-principles methods, the photogalvanic effect(PGE) of the monolayer 2H-MoTe₂ was studied. The results show that under linearly polarized light, the photocurrent function produced by MoTe₂ is consistent with the phenomenological theory. It can generate a larger photocurrent in the photon energies range of 1.6 eV to 1.8 eV (690 nm to 770 nm). The reason for obtaining the higher photocurrent is the electron stimulated transition at the S point in the first Brillouin zone which analyzed using the band structure and density of states. Meanwhile, in the zigzag direction, when the bias voltage is 0.8 V, the photocurrent reaches its peak, but in the armchair direction, when the bias voltage is 0.4 V, the max photocurrent can be reached. The calculation results in this paper can be used to guide the design of photodetectors based on MoTe₂, especially the design of infrared photodetectors.

Key words: photodetector, monolayer 2H-MoTe₂, photogalvanic effect, band structure, density of state, first-principle