【摘要】 基于密度泛函理论的第一性原理平面波赝势方法,研究了单层二硫化钨(WS2)在掺杂Cr和Mo后能带结构的变化,探索不同原子和掺杂量对能带结构的影响,分析了导致能带结构变化的物理机理。计算结果表明:当掺杂量较高时,Mo对单层WS2的能带结构几乎没有影响,而Cr则影响很大,表现为Cr掺杂时能带结构由直接带隙变为间接带隙,且带隙宽度随着掺杂量的增加而逐渐减小。Cr掺杂后所产生的应力是导致能带结构发生变化的直接原因。通过对态密度和电荷密度的分析,揭示了能带变化的根本原因在于Brillouin区中Γ点和K点的本征能量对掺杂所产生的应力的敏感程度不同。更多还原

【Abstract】 The band structure of monolayer WS2 after doping Cr and Mo was investigated according to an ab initio method of plane wave potential technique based on the density function theory. The effects of different atoms and doping concentrations on the band structure were analyzed. The physical mechanism leading to band structural changes was also discussed. The calculated results reveal that the energy band structures of single-layer WS2 are significantly affected due to Cr doping rather than Mo doping at a high doping concentration. The effect of Cr doping manifests as the transition of energy band structure from direct to indirect and the band gap decreases with the increase of doping concentration. It is indicated that strain is due to the change of band structure in the Cr-doped WS2. The change of band structure is because the Brillouin zone Γ and K points of the intrinsic energy to stress are different.更多还原