High-performance solar-blind imaging photodetectors based on micrometer-thick β-Ga2O3 films grown by thermal oxidation of gallium†

Almost all reported high-performance β-Ga₂O₃ films are grown by molecular beam epitaxy, metal organic chemical vapor deposition, and pulsed laser deposition at very high cost and low yield. A method for preparing micron-thick Ga₂O₃ films by in situ thermal oxidation of gallium without vacuum and catalysts is reported for the first time. The results show that the thickness of our typical Ga₂O₃ film exceeds 2 μm, the typical grain size reaches the micrometer level, and it is high-purity single-phase β-Ga₂O₃. The photodetector based on the thick β-Ga₂O₃ film has a responsivity of more than 1.7 A W⁻¹, a light-to-dark current ratio of more than 10³, a detectivity of more than 1.5 × 10¹³ cm Hz^1/2 W⁻¹, self-powered characteristics, and good solar-blind ultraviolet imaging properties. The potential mechanisms of high gain and self-powered characteristics of our device are analyzed. Our research results provide a method for the preparation of high-quality thick gallium oxide films and solar-blind ultraviolet photodetectors.