Biaxial strain-modulated electronic and optical properties of transition metals doped-WSe2 monolayer

We report the effect of biaxial strain (epsilon xy) on the electronic and optical properties of the WSe2 monolayer, doped with transition metal (TM) atoms using density functional theory (DFT) calculations. The TM dopants mainly include Niobium (Nb), Tantalum (Ta), and Rhenium (Re), which are popular choices for p and n-type doping in the WSe2 monolayer. We determine the modulation of electronic bandgap with strain, i. e. Delta Eg/Delta epsilon, have the following order: pristine WSe2 > Nb-doped WSe2 > Ta-doped WSe2 > Re-doped WSe2. All the TM dopants modified the optical responses of the WSe2 monolayer, with the absorption edge shifting towards lower energies (redshift phenomenon). By applying strain, the main changes in the near-infrared (NIR) region to red-visible regions are observed. We believe that knowledge of the behavior of TM-doped WSe2 monolayer with strain is crucial for their further use in emerging optoelectronic device applications.