Interfacial Defect Engineering on Electronic States of Two-Dimensional AlN/MoS₂ Heterostructure

The effects of vacancies and doping defects on the electronic and magnetic states of two-dimensional (2D) AlN/MoS₂ heterostructure are investigated by first-principle calculation. Because of charge transfer from the AlN layer to the interstitial region between layers, the energy band structure of the AlN/MoS₂ heterostructure is not a simple superposition of those of AlN and MoS₂. The energy band alignment can be further tuned by introducing vacancies and doping at the interface. When the AlN layer is decorated by N vacancies or n-type doped, noticeable charge transfer to the conduction band of the MoS₂ layer is observed and the band alignment maintains type-I. However, in the case of p-type doping, for instance, C substituting for N (C_N) in the AlN sublayer, the band alignment changes to type-II. Moreover, Al vacancies and Be_Al/C_N doping produce asymmetrical spin-up and spin-down states, which leads to magnetization of the AlN/MoS₂ heterostructure. The results demonstrate the significant effects of interfacial defects on the physical properties of 2D heterostructures.