Electronic and optical properties of Nb/V-doped WS 2 monolayer: A first-principles study.

The electronic, dielectric, and optical properties of pure and Nb/V-doped WS 2 monolayer are being investigated using the first-principles density functional theory (DFT). The electronic band structure calculations reveal that the pure and doped WS 2 monolayer is a direct band gap semiconductor. It is seen that the doping not only slightly reduces the band gap but also changes the n-type character of pure WS 2 monolayer to the p-type character. Hence, it may be useful for channel material in field effect transistors (FETs). Moreover, the optical studies reveal that the WS 2 monolayer shows a significantly good optical response. However, a small ultraviolet shift is observed in the optical response of the doped case compared to the pristine WS 2 monolayer. This study suggests that the WS 2 monolayer can be a possible optical material for optoelectronic applications, and it can also be a replacement of MoS 2 -based future electronics and optoelectronics.