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 ϵ-Ga2O3/ZnO heterojunction and examined its ruggedness in a high-temperature environment up to 600 K. A photocurrent of up to 0.3 μA and a photo-to-dark current ratio of ∼8000 were observed at room temperature. In addition, the ϵ-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 ϵ-Ga2O3/ZnO photodetector is thus examined, which would provide the basis for further development.
In this Letter, an ultraviolet photodetector constructed on a simple vertical PEDOT:PSS/SiC hybrid heterojunction with superior self-powered performance was reported. Benefitting from the abundant charge carrier concentration in 4H-SiC substrate and the large built-in field at PEDOT:PSS/SiC heterointerface, the SiC based photodetector (PD) realized self-powered responsivity over A/W level, even comparable with many reported 4H-SiC avalanche photodiodes. Upon illumination with deep-UV wavelength at 254 nm, the responsivity, detectivity, and external quantum efficiency of the fabricated PD reached up to 2.15 A/W, 1.9 × 1013 Jones, and 1053%, respectively. Furthermore, the rise/decay time was as fast as 58.6/41.5 ms, the on–off switching ratio was as large as 8.73 × 103, the spectral rejection ratio (R254/R390) was as high as 4.3 × 103, and the lifetime reliability was over 195 days. Serving as a sensing pixel, the designed heterojunction PD demonstrated excellent imaging capability in homemade UV imaging system, showing promising applications in future energy-conservation photoelectronic system.
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