A systematic study on the electronic structure of 3d, 4d, and 5d transition metal-doped WSe2 monolayer

The two-dimensional (2D) transition metal dichalcogenides (TMDCs) are promising materials for future electronic devices applications. WSe2 monolayer is one of the most important TMDC materials with great potential due to its ambipolar behavior. However, the lack of a suitable doping technique is a major obstacle to its practical use as a channel material in field effect transistors (FET). Here, we have systematically studied the electronic structure of 3d, 4d, and 5d transition metals (TM) doped WSe2 monolayer using density functional theory (DFT) calculations. The TM dopants are substituted at the W-site of the WSe2 monolayer. Due to strain induced by the difference of atomic radius between W atom and TM dopants, a decrease in the bandgap observed. The formation energy calculations suggest that doped WSe2 are thermodynamically favourable under the Se-rich condition compared to W-rich conditions. Among all TM dopants, the V, Nb, and Ta are useful p-type dopants, and Re is only an effective n-type dopant for WSe2 monolayer for FETs applications.