Study of -Ga2O3(001)/sapphire (a-plane) heterostructure in wide bandgap solar-blind deep-ultraviolet photodetector

Gallium oxide (Ga2O3) with ultra-wide band gap and high radiation resistance have great potential in solar -blind ultraviolet (UV) photodetectors, but its development is limited by expensive Ga2O3 substrate materials. Sapphire substrate, due to its high hardness, mature production process and low cost, has become one of the most favorable substrate materials for optoelectronic devices. So, Ga2O3-based optoelectronic devices on sapphire substrates hold significant commercial value. In this work, using first-principles density functional theory (DFT) calculations, we investigate the influence of interfacial oxygen concentration on the flGa2O3(001)/sapphire(1120) heterostructure. The results show that the bonding strength between O-terminated and Al-terminated interfaces is strong, indicating favorable thermodynamic stability of this heterostructure. Furthermore, we discover that the metal-O-metal bonding configuration at the interface effectively reduces the number of interfacial defects, increase the built-in electric field strength within the heterostructure, and improves the deposition quality of the fl-Ga2O3 film. This work holds significant implications for the research on f-Ga2O3 solar -blind UV photodetectors based on sapphire substrates.