Epitaxial p-Si/CsPbBr3 heterostructure photodetector with enhanced green responsivity

Traditional silicon are expected to be integrated with emerging halide perovskites to form semiconductor heterostructures, which can facilitate the realization of more modern electronics and optoelectronics but not only solar cells. Currently, the deposition of perovskite films onto silicon substrates predominantly relies on spin-coating techniques, which inherently pose challenges, such as stringent growth prerequisites, compromised film integrity, and inability to foster robust interfacial tuning between the silicon and perovskite films. In this Letter, we report the epitaxial growth of a (100)-oriented CsPbBr3 film directly on a p-type silicon (100) substrate by pulsed laser deposition (PLD), which offers precision control over the interface between the substrate and film. This p-Si/n-CsPbBr3 semiconductor heterostructure manifests distinct p–n heterojunction behavior, characterized by current rectification in the dark state, which indicates the efficient charge separation and transport mechanisms. The device demonstrates visible photodetection capabilities from 400 to 700 nm, showcasing versatility in spectral response. Notably, under 520 nm laser illumination, the device exhibited a remarkable responsivity of 780 mA/W due to electron tunneling from silicon to perovskite film as a direct result of the epitaxial interface, coupled with millisecond-scale response and recovery times, highlighting its potential for high-speed and sensitive photodetector applications. These findings underscore the significant promise of PLD-mediated growth of high-quality epitaxial halide perovskite films on silicon substrates and the formation of heterostructure as a viable route toward complex thin superlattices and integrated devices.