Optical Properties Of MoS₂from First-principles Calculations

Molybdenum disulfide (MoS2) is a typical layered transition metal binary compound, has excellent thermal stability and chemical stability and has been widely used in solid lubricant, electrode materials and reaction catalyst, etc. At the same time, as a graphene-like layered transition metal compound, single-layer MoS2has a very good prospect in assisting graphene or even take graphene’s place because of it outstanding optical and electrical property. Single-layer MoS2has been paid much attention in the application of transistors and electronic probes. Multi-layer MoS2are now being researched in the optical sensor field. Researches about the optical properties and electronic structure of bulk, single-layer and multi-layer MoS2has been performed in this article:1. We perform the calculation on the imaginary part and the real part of dielectric function of the single-layer and bulk MoS2on the basis of the band structure calculation, the result has been compared with the experimental data and fits well. We point out the relationship between the interband transitions and the peaks in the dielectric function.2. We optimize the structure of multi-layer MoS2and compare the band structure of bulk MoS2with single-layer and multi-layer MoS2. The difference of band gap between structures has been analyzed. The dielectric function of multi-layer MoS2has been calculated and analyzed.3. According to the Lorentz dispersion theory, the optical coefficients changes following the changes of the incident ray frequency. We export the familiar optical coefficients such as the energy loss spectrum L(ω),the absorption coefficient α(ω),the refractive index n(co),the reflectivity R(ω) and the extinction coefficient k(ω). Each coefficient has been described with curve and compared between different layers.