Abstract: The electronic structure and optical property of 2D $ MoX_{2}/MgPSe_{3} $ (X=S, Se) is studied by density functional theory. The analysis of energy band structures and density of states indicates that $ MoSe_{2}/MgPSe_{3} $ and $ MoSSe/MgPSe_{3} $ II heterostructures have significant type-II band, and the conduction band minimum (CBM) and valence band maximum (VBM) of heterostructure are on both sides of the redox potentials of water (-4.44, -5.67 eV) respectively. This energy band structure is conducive to the application of the material in photocatalytic water splitting into hydrogen and oxygen. By applying uniform biaxial stress to $ MoX_{2}/MgPSe_{3} $, it is found that biaxial strain has an obvious linear regulating effect on the band gap of $ MoX_{2}/MgPSe_{3} $, and this linear regulating effect has application value in pressure transducers. The calculation of the light absorption coefficient finds that the absorption intensity of $ MoSSe/MgPSe_{3} $ in the ultraviolet region is significantly higher than that of $ MgPSe_{3} $ and $ MoX_{2} $ alone, indicating that heterostructures play an important role in improving the optical property of the material.
Keywords: heterostructure; photocatalytic; biaxial strain; vacancy; light absorption