High-performance layer-structured Si/Ga2O3/CH3NH3PbI3 heterojunction photodetector based on a Ga2O3 buffer interlayer

Organic–inorganic metal halide perovskite-based photodetectors (PDs) have attracted great attention because they exhibit extraordinary optoelectronic performances due to advantages such as a low trap-state density and large absorption coefficient. As a buffer layer, Ga2O3 can block electron hole recombination, passivate an Si surface, reduce trap density, and improve the ability of electron tunneling. Here, we demonstrate a trilayer hybrid structure (Si/Ga2O3/CH3NH3PbI3) composed of an n-type silicon wafer, Ga2O3 interlayer, and CH3NH3PbI3 thin film. The effect of different Ga2O3 layer thicknesses on the characteristics of a PD was studied, which shows that the responsivity first increases and then decreases with an increase in the Ga2O3 film thickness; the optimized Ga2O3 thickness is 300 nm. Additionally, the optimal responsivity, detectivity, and the rise and decay times are 7.2mAW-1, 7.448x1010 Jones, and 39 and 1.7 ms, respectively. This device has a better performance because Ga2O3 and perovskite have a matched energy level. We believe our work could provide a new way to fabricate high-performance optoelectronic devices.