Tunable electronic properties of AlAs/WSe2 heterojunctions with Sb/Mo doping under external electric field and biaxial strain

In this paper, the geometrical arrangement, electronic structure and optical properties of AlAs/WSe₂ heterojunctions as well as Sb/Mo doped AlAs/WSe₂ heterojunctions are investigated on the basis of density-functional theory (DFT). The geometric structures of three heterostructures-A1 (undoped), B1 (Sb-doped), and C1 (Mo-doped)-are optimized to determine their stability. The results reveal that all heterojunctions exhibit reduced bandgaps compared to their constituent monolayers, thereby enhancing photogenerated carrier separation efficiency. In addition, the AlAs/WSe₂ heterostructure demonstrates remarkable band structure tunability under external electric fields or mechanical strain, enabling controllable type-I to type-II band alignment transitions. While the three AlAs/WSe₂ heterostructures exhibit slight variations in light absorption capacity, their absorption coefficients are consistently and significantly higher than those of individual AlAs and WSe₂ monolayers. These findings demonstrate that AlAs/WSe₂ heterostructures exhibit remarkable potential for optoelectronic device applications, particularly in photodetection.