Density functional theory-based quantum-computational analysis on the strain-assisted electronic and photocatalytic properties of BX-MSSe (X = P, As and M = Mo, W) heterostructures

To overcome environmental problems and the energy crisis, water splitting through solar energy for the production of hydrogen fuel is a promising technique. Efficient and low-cost photocatalyst are highly desired. In the recent era, van der Waal (vdW) heterostructures have gained considerable attention due to their promising properties. Hybrid density functional theory is used to calculate the electronic and photocatalytic properties of BX-MSSe (X = P, As and M = Mo, W) vdW heterostructures. Most stable stacking is figured out among different stacking from their relaxation energy. The stability of the stable stacking is confirmed through phonon calculations. Calculated band structure shows that BAs-MoSSe and BP-WSSe have direct band gap nature while the BP-MoSSe and BAs-WSSe have indirect band gap nature. BAs-MoSSe has Type-I band alignment while BP-MoSSe, BAs-WSSe and BP-WSSe have type-II band alignment. The creation of heterostructures broadened the optical absorption from the infrared to the ultraviolet region of the solar spectrum. To tune the properties of these heterostructures compressive and tensile strain is applied. Switching in band alignment is predicted in these heterostructures with the applications of strain. Based on valence and conduction band edges potentially the photocatalytic behavior for pH = 0 is investigated, which confirms that in unstrained conditions BP-MSSe (M = Mo, W) heterostructures are efficient photocatalyst.