基于第一性原理的掺杂单层WS 2的光电效应

Photogalvanic Effect of Doped Monolayer WS_(2) Based on First-Principles

基于非平衡态格林函数-密度泛函理论,采用第一性原理方法,计算了VA族元素(N、P、As或Sb)掺杂单层WS 2的光电效应,并解释了掺杂提高光电效应的微观机理。结果表明:在线性极化光照射下,单层WS 2中可以产生光电流。由于掺杂降低了单层WS 2的空间反演对称性,导致N、P、As或Sb分别掺杂的单层WS 2的光照中心区产生的光电流明显提升。其中N掺杂的效果最好,掺杂后的单层WS 2在光子能量3.1 eV时获得最大光电流(1.75),并且偏振灵敏度达到最大(18.1),P、As、Sb分别掺杂的单层WS 2在光子能量3.9 eV时取得较大的光电流,并且有较高的偏振灵敏度。研究结果表明通过掺杂能够有效增强光电效应,获得更高的偏振灵敏度,揭示了掺杂单层WS 2在光电子器件领域潜在的应用前景。

Based on the non-equilibrium Green function-density functional theory,the photoelectric effect of doped monolayer WS 2 with VA group elements(N,P,As or Sb)was calculated by first-principles,and the microcosmic mechanism of doping to improve the photogalvanic effect was explained.The results show that photocurrent can be generated in the monolayer WS 2 under linearly polarized light.Since the doping reduces the spatial inversion symmetry of the monolayer WS 2,the photocurrent generated by the illuminated central area of the monolayer WS 2 doped with N,P,As,or Sb significantly increases,and the photocurrent and the polarization angle show a perfect sinusoidal relationship,which conforms to the phenomenological theory.Among them,the effect of N doping is the best.The doped monolayer WS 2 obtains the maximum photocurrent(1.75)when the photon energy is 3.1 eV,and the polarization sensitivity reaches the maximum(18.1).The monolayer WS 2 doped with P,As and Sb achieves a larger photocurrent when the photon energy is 3.9 eV,and has a higher polarization sensitivity.The research results show that the doping can effectively enhance the photogalvanic effect and obtain higher polarization sensitivity,revealing the potential application prospects of doped monolayer.