MoTe2的电子结构及光学性质的理论研究

利用密度泛函理论第一性原理方法对MoTe_2的能带结构、能态密度和光学性质进行了理论计算,得到能带结构、态密度、光吸收谱、能量损失谱和介电函数等光学性质。结果表明:MoTe_2具有间接带隙宽度为1.066 eV的半导体材料,价带主要由Mo的5s4p价电子和Te的5s5p价电子起主要作用;导带由Mo和Te的4d价电子起主要作用。由获得的光学性质可知,介电函数的实部和虚部的峰值都出现在低能区;位于可见到紫外区域的光子具有很强的吸收,最大吸收系数为2.84×10~5cm~(-1);同时在光子能量为16.40 eV处出现了共振现象,其它区域内电子之间共振非常微弱。这些光学性质奠定了该材料在制作微电子和光电子器件方面的作用。

STUDYON THE ELECTRIC STRUCTURE AND OPTICAL ELECTRICAL CHARACTERISTIC OF MoTe2

In this paper, the first-principle of ultra-soft pseudopotential method of density functional theory is used to theoretically calculate the energy band structure, energy density and optical properties of MoTe₂. The results show that MoTe₂ is a semiconductor material with an indirect band gap and the bandgap width is1.066eV. The formation of the valence band and the conduction band is caused by the valence electrons of Mo and Te. Specifically, the formation of the valence bands by the 5s4p states of Mo and the 5s5p states of Te play different roles, the conduction band formation, the 4dstate of Mo and Te have a greater effect, other states has only a little effect. Through the calculation and analysis, the optical properties of MoTe₂ can be obtained:dielectric function, complex refractive index, energy loss function and so on. It is found that MoTe₂ has a strong absorption of visible photons in the ultraviolet region with a maximum absorption coefficient of 2.84×10⁵cm^-1. MoTe₂ has a resonance phenomenon at about 16.40eV, and the resonance between electrons is very weakin other regions. The optical properties of MoTe₂ lay a foundation for its role in the fabrication of microelectronics and optoelectronic devices, which can provide theoretical reference for further study of MoTe₂ material in the future.