不同浓度F掺杂MoS_2性质的第一性原理计算研究

First Principles Calculations of Properties of Different F-doped MoS_2

MoS_2二维材料由于其本身就具有直接带隙且带隙不为零,具有优于石墨烯的能带结构,是良好的半导体材料,在电学、磁学、及未来电子器件等方面都有良好的性质和应用前景。利用第一性原理方法,通过替位掺杂的方式,研究了不同浓度F掺杂单层MoS_2的能带结构和各种态密度图,并与本征单层MoS_2及文献中的掺Cl、掺O结果做了对比,分析了各自的电子结构、导电性和磁性。结果发现:掺F后单层MoS_2由直接带隙变成间接带隙,单层MoS_2的禁带宽度从本征的1.718e V减小到1.301 e V,且随着F掺杂浓度的增加,带隙更加变窄,体系的导电性更加增强。带隙的调节程度大于文献中掺Cl的效果而小于掺O的效果。磁性方面,本征的MoS_2无磁性,发现掺F后出现了一定磁性,且随着F掺杂浓度的增加其磁性增加。这些结果有利于对MoS_2优化改性和调控从而在微电子器件和半导体自旋电子学方面的应用。

MoS_2two-dimensional material is a better semiconductor materials than graphene in electrical and magnetic due to its own direct band gap and non-zero band gap band structure. We have a good application prospects in future electronic devices. In this paper,the band structure and density of states spectra of single-layer MoS_2 with different concentrations of F-doped were studied in first-principles method. The conductivity and magnetic properties were analyzed. It is found that the energy gap of the monolayer MoS_2 is reduced from 1. 718 e V of direct band gap of the intrinsic single layer MoS_2 to 1. 301 e V of indirect band gap. With the increase of the F doping concentration,the band gap becomes narrow and the conductivity is more enhanced. The degree of change of band gap is larger than that of Cl in literature and less than that of O. Besides,the intrinsic MoS_2 is non-magnetic. Magnetic properties show that,after F doped,the magnetic properties will increase with the increase of the F-doping concentration. These results are useful for the MoS_2 modification and application in microelectronic devices and semiconductor spin electronics.