Asymmetric Band Alignments and Remark Defect Tolerability at the Interface of High-k Dielectric Sb2O3 and 2D Semiconductor MoS2

Inorganic molecule crystal Sb ₂O ₃ has been identified as a promising high-k dielectric for direct integration with the two-dimensional (2D) semiconductor MoS ₂. However, a comprehensive understanding of their interface remains elusive, impeding their applications in high-performance 2D electronics. In this study, we elucidate the interfacial interaction, and electronic and defect properties of the Sb ₂O ₃/monolayer MoS ₂ interface using in-depth first-principles calculations. We find that a high-performance quasi-van der Waals interface can be formed between Sb ₂O ₃ and monolayer MoS ₂, as evidenced by weak interfacial interaction, a dangling-bond-free interface, insignificant electron-hole puddle redistribution, and the preserved semiconducting properties of monolayer MoS ₂. Notably, the interface exhibits a remarkable defect tolerance capability during integration, as Sb ₂O ₃ cluster vacancies (the dominant defect in Sb ₂O ₃) neither introduce midgap states nor significantly affect the interface properties. Besides, our study reveals a strongly asymmetric type-I band alignment at the interface, where the conduction and valence band offsets are predicted to be 1.07 and 0.25 eV at the PBE level, respectively. Our work offers a comprehensive understanding of the quasi-vdW interface between Sb ₂O ₃ and monolayer MoS ₂, which could be useful for the development of inorganic molecular crystals as high-k dielectrics for high-performance 2D electronic devices.