Effects of doping Ti, Nb, Ni on the photoelectric properties of monolayer 2H-WSe2

The photocurrent of Ti, Nb, Ni substitution-doped monolayer 2H-WSe2 is calculated by the first-principles method based on the Keldysh nonequilibrium Green's function-density functional theory. The photogalvanic effect(PGE) photocurrent can be generated in the monolayer 2H-WSe2 under the vertical irradiation of linear polarized light, However, it is generally very small. Calculation results show that the Nb and Ti-doped systems exhibit the characteristics of semi-metal, while the Ni-doped system tends to transform into metals. The substitutional doping of Nb, Ti, and Ni atoms can effectively enhance the photocurrent and the polarization sensitivity of monolayer 2H-WSe2.This excellent performance is mainly attributed to the fact that the doping introduces multiple impurity energy bands crossing the Fermi energy level, which becomes a bridge for electronic transitions, thus effectively enhancing the photocurrent.

Automated summary

Substitutional doping of Ti, Nb, and Ni atoms can effectively enhance the photocurrent and polarization sensitivity of monolayer 2H-WSe2, mainly due to the impurity energy bands introduced by doping, which act as a bridge for electronic transitions.