Tuning the Electronic and Optical Properties of the ZrS2/PtS2 van der Waals Heterostructure by an External Electric Field and Vertical Strain.

Abstract

Two-dimensional (2D) material-based heterostructures gain increasing interest due to their extraordinary properties and excellent potential for the optoelectronic devices. This study deals with modulation of electronic and optical properties of the ZrS2/PtS2 van der Waals heterostructure under vertical strain and an external electric field based on first principles calculation. Different stacking of ZrS2 and PtS2 layers are considered for the heterostructure formation and the most stable structure with lowest binding energy is selected for further calculations. The stable ZrS2/PtS2 heterostructure shows an indirect band gap of 0.74 eV, which is smaller than that of both ZrS2 and PtS2 monolayers. With the applied external electric field, the band gap value of the ZrS2/PtS2 heterostructure increases with the negative electric field and decreases with the positive electric field. It is observed that the indirect-to-direct band gap transition occurs when the highest negative value of the electric field is applied. In the case of vertical strain applied to the heterostructure, with an increase in compressive strain, the band gap decreases and vice versa for tensile strain. Optical absorption spectra show significant absorption in the visible light region to the ultraviolet light region. This study shows that the electronic and optical properties of ZrS2/PtS2 heterostructures can be modulated by using vertical strains and an external electric field.