High-performance high-temperature solar-blind photodetector based on polycrystalline Ga2O3 film

In this paper, high-temperature solar-blind photodetectors were fabricated based on polycrystalline Ga2O3 (poly-Ga2O3) film which was prepared by annealing amorphous Ga2O3 (a-Ga2O3) film in oxygen atmosphere. The effects of annealing temperature on the properties of the material and the performances of the corresponding Metal–semiconductor–metal photodetector were investigated. The main factors affecting device performance are attributed to the oxygen vacancy defect concentration in Ga2O3 and the effective Schottky barrier height and width between gold and Ga2O3. We found that the detector based on 650 °C annealed poly-Ga2O3 showed the best solar-blind detection photoelectric performance and good thermal stability. More interestingly, the device has fast response recovery speed (0.16 s), low dark current (≤0.1 nA) and high photo-to-dark current ratio (≥97) at 200 °C high temperature operation. These performances are even better than the reported high-temperature photodetectors based on high-quality crystal Ga2O3 thin film or Ga2O3 bulk. Besides, our method that avoid direct high-temperature growth of poly-Ga2O3 and may be beneficial to its commercial large-area production and further cost reduction.