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

• Published in: Journal of alloys and compounds 2020-12, Vol.847, p.156536, Article 156536
• Main Authors: Zhou, Hai-tao, Cong, Lu-jia, Ma, Jian-gang, Chen, Ming-zhu, Song, Dong-yu, Wang, Hong-bin, Li, Peng, Li, Bing-sheng, Xu, Hai-yang, Liu, Yi-chun
• Format: Article
• Language: English
• Subjects: Annealing; Annealing temperature effect; Dark current; Gallium oxides; High temperature; High-performance; High-temperature solar-blind photodetector; Metal–semiconductor–metal structure; Photoelectricity; Photometers; Poly-Ga2O3 film; Polycrystals; Thermal stability; Thin films
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.156536

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. •Thermal annealing transforms the amorphous Ga2O3 film into a polycrystalline structure.•Oxygen vacancy and Schottky barrier affect the performance of the MSM Ga2O3 photodetector.•Photodetectors based on 650 °C annealed poly-Ga2O3 exhibit high-performance at 200 °C.•Conversion of Ga2O3 from amorphous to polycrystalline avoids the direct high-temperature growth.