Ultrathin BiOSe/Si Heterojunction Photodetector with Tunneling Oxide Passivation for Enhanced Optoelectronic Performance.

Two-dimensional (2D) materials have garnered significant attention for next-generation optoelectronic devices due to their exceptional physical properties. This study introduces a high-performance ultrathin BiOSe/Si heterojunction photodetector with tunneling oxide passivation, fabricated using a transfer-free pulsed laser deposition method. The BiOSe layer exhibits strong air stability and compatibility for practical applications. By incorporating a thin SiO tunneling layer, the heterostructure achieves a low dark current (∼22.3 nA/cm), a high on/off ratio (∼8 × 10), and a responsivity of 23.0 A/W. Compared to traditional CdS/Si devices, this photodetector demonstrates superior performance, including faster response time and higher stability. These findings underscore the potential of BiOSe/Si heterostructures for advanced photonic and optoelectronic applications.