The Photoelectric Properties Of MoS₂ Nanostructures

All of the computations are performed using the density functional theory(DFT) method, as implemented in the WIEN2 K simulation package through first-principles calculations. Generalized gradient approximation(GGA) was adopted to describe these calculations. Our main purpose is to study the photoelectric properties of MoS2 nanostructures in this paper.Firstly, the electronic structures and optic properties of Mn and B, C, N co-doped MoS2 monolayer have been studied through GGA and GGA+U method. It is shown that the monolayer MoS2 will reflect magnetism when Mn and C co-doped. However, the co-doped systems with Mn-B and Mn-N atoms exhibit semiconducting behavior and the energy band gaps are smaller than the corresponding pristine forms. The dielectric function, absorption, reflectivity and refractivity of Mn-B, C, N co-doped systems all reflect the phenomenon of red shift. In order to determine whether the co-doped system is easily come true in the experiments, we calculate the formation energy of the MoS2 monolayer. The formation energy analysis shows that MoS2 monolayer with Mn and C co-doped is the most stable spin configurations. Mn and C co-doped MoS2 monolayer will be realized easily in the experiments.Secondly, the electronic structure and optic properties of Mo, S vacancy defect and V-doping have been studied through the generalized gradient approximation(GGA) method. The results indicate that the monolayer MoS2 with Mo, S vacancy and V-doped will gain the property of magnetic semiconductor.The optic properties of these V-doped and vacancy defect structures all reflect the phenomenon of red shift. In the meanwhile, the absorption edges of MoS2 monolayer with Mo vacancy defect and V-doped occur the largest red shift.Furthermore, Armchair and Zigzag nanoribbon are dealt with F atoms or vacancy defect. As is known to all, Armchair nanoribbon shows semiconducting behavior and Zigzag nanoribbon shows a metallic property. We expect that vacancy defect and the edges what dealt with F atoms can improve the photoelectric of Armchair nanoribbons as well as change Zigzag nanoribbons' metallic property. From the results we can get to know that the metallic property of Zigzag nanoribbon is not changed. With the impact of F atoms and S vacancy defect, the Armchair nanoribbons reflect metallic property. The Armchair nanoribbon with Mo vacancy defect shows semiconducting behavior and the band gap become smaller than the primitive state. And the band gap is 0.14 eV. In the meanwhile, the optic property of Mo vacancy defect reflect the phenomenon of red shift. The 2S vacancy defect makes the Armchair nanoribbon become half-metallic.Lastly, the crystal structure and photoelectric properties of interface growth of MoS2/ZnTe heterobilayer have been calculated. According to the corresponding to the different atoms, we discuss five configurations including Te-Mo, Te-S, Hollow, Zn-Mo, Zn-S. Through our researches, we can find that the monolayer MoS2/ZnTe all reflect semiconducting behavior and the energy band gaps become smaller than before.The optic properties(dielectric function, absorption, reflectivity and refractivity) of MoS2/ZnTe systems all reflect the phenomenon of red shift.