Tunable electronic and photodiode characteristics of Janus WSeTe: A first-principles study

Janus transition metal chalcogenides have captured the wide attention due to the asymmetric facial properties. Using the first principles calculations in combination with the nonequilibrium Green's function method, we studied the electronic structure, transport and optical properties of WSeTe monolayer. The results show that the electronic properties of WSeTe monolayer can be effectively regulated by biaxial strain and electric field. To be specific, a phase transition from semiconductor to metal accompanied with direct to indirect gap transition can be achieved by applying the biaxial strain. Besides, the optical properties of WSeTe monolayer can also be significant improved in the visible light region with a red and blue shift of optical absorption peaks under the tensile and compressive strain respectively. For devices based on WSeTe monolayer, the current switching ratios are up to 1010, which represent a perfect diode behavior can be observed in the case of ±12% strain. Furthermore, for pin-junction based on WSeTe monolayer, a considerable photocurrents which can be obtained from the light absorption coefficients located in the scope of 1∼3 eV, mean a strong photoelectronic response to the red and orange light region. The results show great potential for the application of WSeTe monolayer in switching and photoelectric devices.