单层MoS_2分子掺杂的第一性原理研究

First principles study on molecule doping in MoS_2 monolayer

基于密度泛函理论的第一性原理平面波赝势方法的计算,研究了通过吸附不同有机分子对单层MoS2进行化学掺杂.计算结果表明有机分子与MoS2单层衬底间的相互作用主要是范德瓦尔斯作用力.吸附不同有机分子的单层MoS2结构均表现出间接带隙的特征,还表明吸附TTF分子的单层MoS2结构表现出n型半导体的特质,而吸附TCNQ,TCNE两种分子的单层MoS2结构均表现出p型半导体的性质,这些结果表明可以通过改变吸附的分子来实现对单层MoS2的掺杂类型的调控.本文的研究结果将对单层MoS2在晶体管中的应用提供理论基础和指导.

The chemical doping of organic molecules adsorbed on MoS2monolayers are systematically studied by using planewave pseudo-potential method based on the density functional theory. Our results indicate that the interaction between organic molecules and the MoS2monolayer substrate is of van der Waals＇ type of force. Structure of monolayer MoS2which adsorbs different organic molecules, exhibits indirect bandgap characteristics, and the energy band structure of monolayer MoS2which adsorbs TTF molecules exhibits n-type conducting characteristics. However, the structures of monolayer MoS2which adsorbs TCNQ or TCNE molecules would exhibit p-type conductivity characteristics. Thus, the results indicate that the doping type of molecules in monolayer MoS2can be regulated by adsorbing different molecules.Results of this study may providea theoretical basis for single-layer MoS2transistor and guidance for it in the application.