Aqueous‐Printed Ga₂O₃ Films for High‐Performance Flexible and Heat‐Resistant Deep Ultraviolet Photodetector and Array

Abstract High deep‐ultraviolet (DUV) sensitivity and excellent flexibility of ultrathin gallium oxide (Ga₂O₃) film with an ultrawide bandgap endow its extreme propensity in flexible DUV photodetector especially for space exploration and wearable electronics. However, an efficient strategy with high throughput and low cost is highly deficient to realize flexible and robust Ga₂O₃ DUV photodetectors to face potential harsh environments. In this work, flexible and heat‐resistant Ga₂O₃ DUV photodetectors based on optimized inkjet printing with environmental‐friendly aqueous solvent are demonstrated. The dynamic evolution from Ga(NO₃)₃ precursor to crystalline Ga₂O₃ film has been explicitly uncovered. Photodetectors based on printed ultrathin Ga₂O₃ films on rigid substrate exhibit outstanding performance, including high photo‐to‐dark current ratio about 10⁶, considerable responsivity of 1.3 A W⁻¹, superior detectivity of 1.46 × 10¹⁴ Jones, and fast decay time of 0.026 s under 254 nm illumination. In addition, flexible devices on mica substrate not only retain outstanding photoelectrical performance, but also demonstrate excellent mechanical flexibility and thermal stability. Moreover, benefiting from the uniformity of the pixels by high‐throughput inkjet printing, the Ga₂O₃ DUV photodetector array presents excellent sharp‐imaging capability. This work provides a feasible strategy for printable, flexible, and harsh‐environment‐resistant Ga₂O₃ DUV photodetectors toward space exploration and wearable electronics.