Preparation and Characterization of β-Ga2O3-based Photo detectors for UV Detection Applications
Résumé
Compact photodetectors with a significant response in the UVC spectral band (100-280 nm) present a growing interest since of their potential applications to "New Space" nanosatellite constellation missions. Gallium oxide, with an already intrinsic ultra wide bandgap of 4.9 eV at 253 nm, can be engineered further into the ultraviolet (UV) by alloying it with Al. This next generation of MUV (200-300 nm) photodetectors is uniquely suitable for solar radiation from Space, and specifically the Herzberg continuum (200-242nm) that plays an important role in regional climate change through interactions with stratospheric ozone. This work presents the photolithographic, packaging and characterization of β-Ga 2 O 3-based photodetectors destined to study and improve our understanding of the solar UV impact on the Earth's climate. Different tests are used to confirm the final selection of protoflight detectors, such as photo-electric performance, photoresponse time and thermal cycle studies. These detectors are then projected to be integrated on a nanosatellite (INSPIRE-Sat 7, a "2U" cubesat) to be launched in early 2023 to monitor the absolute solar spectral irradiance and variability in the Herzberg continuum to better understand the stratospheric ozone response to solar UV irradiance changes. Results suggest that β-Ga 2 O 3-based photodetectors may certainly be a promising candidate for optoelectronic applications in the UV-detection for its high responsivity and low dark current, "solar-blindness above 250 nm" and radiation hard properties. Thermal influence, photo-responsivity and response time are reported.
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