High Performance Solar-Blind UV Photodetector Based on C₈-BTBT/β-Ga₂O₃ Core–Shell Structure pn Heterojunction

The development of β-Ga 2 O 3 -based pn heterojunction holds significant promise for next-generation solar-blind ultraviolet photodetection, yet remains fundamentally constrained by the material’s inherent p -type doping challenges. Herein, we propose an organic–inorganic heterointegration strategy with oxygen vacancy engineering to overcome these limitations. Through dipping mechanically exfoliated β-Ga 2 O 3 single crystals into heated and melted dioctyl benzothiophene (C 8 -BTBT) for van der Waals assembly, we demonstrate a pn heterostructure. Postannealing at 800 °C effectively reduces oxygen vacancy concentration, suppressing dark current through trap-assisted recombination mitigation. The optimized device achieves exceptional performance with ultrahigh photo-to-dark current ratio ( I photo / I dark = 1.05 × 10 5 @ −40 V), superior detectivity (2.04 × 10 12 Jones), and fast response speed. This work provides a feasible strategy for the development of high performance β-Ga 2 O 3 -based solar-blind UV photodetectors and may promote their application.