基于密度泛函理论的B、P掺杂MoS_(2)/Gr异质结光电性能增强的调制机理

Microscopic Mechanism For Enhancing the Optoelectronic Performance of B and P-Doped MoS_(2)/Gr Heterojunctions Based on Density Functional Theory

为了扩展能够提升光调制器性能的新型复合材料的相关理论,基于密度泛函理论,研究了B、P掺杂MoS_(2)/Gr异质结的光电性能的调制机理。结果表明:形成异质结后,异质结层间存在着由石墨烯层向MoS_(2)层表面的电子转移;掺杂原子后,异质结的石墨烯层和二硫化钼层之间转移的电子进行了重分配,主要发生了B原子向C原子与P原子向S原子,以及B原子与P原子间的电子转移,导致掺杂P原子附近电子向层间聚集的现象。费米能级附近,掺杂原子和石墨烯与二硫化钼之间发生轨道杂化,产生杂化能级,使得载流子跃迁的能隙变窄,导致材料与光在近红外甚至以下的低能区作用增强,且部分光学吸收峰向低能区方向移动。此外,通过改变掺杂原子浓度和配比可以一定程度上实现对异质结低能区光学性能的调控。

To extend the theory related to new composite materials that can enhance the performance of optical modulators,the modulation mechanism of the optoelectronic properties of Bdoped and Pdoped MoS_(2)/Gr heterojunctions is investigated.The results show that after the formation of the heterojunction,there is an electron transfer from the graphene layer to the surface of the MoS_(2) layer between the heterojunction layers;after the doping of atoms,the electrons transferred between the graphene and molybdenum disulfide layers of the heterojunction are redistributed,and the electron transfer from the B atom to the C atom,the P atom to the S atom,and between the B atom and the P atom mainly occurs,leading to the phenomenon of electron aggregation between the layers near the doped P atom.Near the Fermi energy level,orbital hybridization between the dopant atoms and graphene and molybdenum disulfide occurs,resulting in a narrower energy gap for carrier jumps,leading to enhanced interaction with light in the low energy region in the nearinfrared and even below,and some optical absorption peaks move towards the low energy region,the modulation of the optical properties in the lowenergy region of the heterojunction can be achieved to some extent by changing the concentration and ratio of doped atoms.