Effect of biaxial strain on the electronic structure of Nb-doped WSe2 monolayer: a theoretical study

Strain engineering is an effective strategy to tune the electronic structure of two-dimensional (2D) materials. In this work, we analyzed the effect of biaxial strain on the electronic structures of Nb-doped WSe
₂
monolayer (ML) by using the density functional theory (DFT). The bandgap of Nb-doped WSe
₂
ML is calculated as 1.43 eV under unstrained condition and it is an effectual p-type direct bandgap semiconductor. The formation energy calculations suggested that Nb-doped WSe
₂
ML under biaxial strain varying from -5% to +5% are thermodynamically favorable under the Se-rich experimental conditions. By comparing the rate of bandgap tunability of Nb-doped WSe
₂
ML, it is clear that the biaxial tensile strain is more effective in tuning the electronic structure compared to the compressive strain.