Deep-to-shallow level transition of Re and Nb dopants in monolayerMoS2with dielectric environments

We investigate the effects of dielectric environments on the transition levels of Re and Nb dopants in monolayer ${\mathrm{MoS}}_{2}$ through density functional theory calculations. The inherently weakly screened Coulomb interaction in free-standing monolayer ${\mathrm{MoS}}_{2}$ makes the dopant electrons and holes strongly bound, and the Re and Nb impurities are found to produce deep levels. It is shown that when the monolayer ${\mathrm{MoS}}_{2}$ is placed near high permittivity dielectrics the screened Coulomb interaction induces carrier delocalization with generating shallow levels.