A self-powered β-Ga2O3/CsCu2I3 heterojunction photodiode responding to deep ultraviolet irradiation

In this paper, a lead-free halide perovskite CsCu2I3 film with high stability was prepared by the anti-solvent assisted crystallization method. Then, we coupled it with Ga2O3 to prepare a corresponding heterojunction deep ultraviolet (UV) photodetector. After testing, we concluded that the photodetector is sensitive to 254 nm UV light. The photodetector has good reproducibility, and has an ultra-high photo-to-dark current ratio (PDCR) of more than 105. In addition, under a bias of 10 V and an illuminated intensity of 200 μW/cm2, the responsivity (R) and specific detectivity (D*) reached 20 mA/W and 107 cm Hz1/2 W−1 (Jones), and the external quantum efficiency (EQE) is 10%. Meanwhile, the prepared photodetector could operate at zero bias, i.e., self-powered operation, along with a photocurrent of about 1 nA under illumination with UV light intensity of 200 μW/cm2.