A systematic study on the electronic structure of 3d, 4d, and 5d transition metal-doped WSe_2 monolayer

摘要

The two-dimensional (2D) transition metal dichalcogenides (TMDCs) are promising materials for future electronic devices applications. WSe_2 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 WSe_2 monolayer using density functional theory (DFT) calculations. The TM dopants are substituted at the W-site of the WSe_2 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 WSe_2 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 WSe_2 monolayer for FETs applications.