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 (Ga 2 O 3 ) 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 Ga 2 O 3 DUV photodetectors to face potential harsh environments. In this work, flexible and heat‐resistant Ga 2 O 3 DUV photodetectors based on optimized inkjet printing with environmental‐friendly aqueous solvent are demonstrated. The dynamic evolution from Ga(NO 3 ) 3 precursor to crystalline Ga 2 O 3 film has been explicitly uncovered. Photodetectors based on printed ultrathin Ga 2 O 3 films on rigid substrate exhibit outstanding performance, including high photo‐to‐dark current ratio about 10 6 , considerable responsivity of 1.3 A W −1 , superior detectivity of 1.46 × 10 14 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 Ga 2 O 3 DUV photodetector array presents excellent sharp‐imaging capability. This work provides a feasible strategy for printable, flexible, and harsh‐environment‐resistant Ga 2 O 3 DUV photodetectors toward space exploration and wearable electronics.