Due to the spread of the new coronavirus (SARS-CoV-2), new sterilization technology is gathering much attention. A wide range of light irradiation sterilization technology using ultraviolet light is very effective for prevention of virus spread. In the wavelength range of ultraviolet light (~265 nm), AlGaN-based LEDs are being actively researched. In the shorter wavelength region, mercury lamps (185 and 254 nm) and gas light sources (222 nm) are also being studied. However, in the region called

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... vacuum ultraviolet (VUV), where the wavelength is 200 nm or less, there are few candidates for light emitting elements. MgZnO is one of the candidates because this material can theoretically emit light up to 160 nm. Emission at around 240 nm from MgZnO alloy thin films was reported in 2016, then emission at VUV region (~199 nm) was observed in 2019. It is the first to realize vacuum ultraviolet light emission by a semiconductor, and it is very promising as a sterilization device in the ultra-short-wave region.