High-temperature reliability of all-oxide self-powered deep UV photodetector based on ε-Ga2O3/ZnO heterojunction

Ga2O3-based photodetectors are promising for deep ultraviolet (DUV) detection owing to the relatively large bandgap (>4.5 eV) of Ga2O3. High-temperature applications, such as flame detection and aerospace have been a major challenge to the reliability of electronic devices including photodetectors. All-oxide electronic devices have great potential for applications that require high thermal stability. Therefore, we constructed an all-oxide self-powered DUV photodetector based on epsilon-Ga2O3/ZnO heterojunction and examined its ruggedness in a high-temperature environment up to 600 K. A photocurrent of up to 0.3 mu A and a photo-to-dark current ratio of similar to 8000 were observed at room temperature. In addition, the epsilon-Ga2O3/ZnO heterojunction remained functional even at an ambient temperature of 600 K. It was also found that sensing performance including photo-to-dark current ratio (PDCR), responsivity, detectivity, and external quantum efficiency degraded as the temperature increased. Detailed generation/recombination processes, as well as carrier transport, were explored to reveal physical insights. The thermal stability of the epsilon-Ga2O3/ZnO photodetector is thus examined, which would provide the basis for further development.