Solar-Blind Ultraviolet Detectors Based on High-Quality HVPE α-Ga2O3 Films With Giant Responsivity

The MSM structures based on high-quality 1.6- $\mu \text{m}$ -thick $\alpha $ -gallium oxide (Ga2O3) films grown by the halide vapor phase epitaxy with Ti/Ni interdigital contacts were developed for the detection of short-wave ultraviolet (UVC) radiation. The spectral dependences of responsivity, external quantum efficiency (EQE), and detectivity of MSM structures based on $\alpha $ -Ga2O3 were studied in the wavelength range of 205–260 nm. The responsivity, the EQE, and the detectivity are $7.19\times104$ A $\times \,\,\text{W}^{-{1}}$ , $3.79\times105$ arb.un., and $1.12\times1018$ Hz $^{\text {0.{5}}} \times $ cm $\times \,\,\text{W}^{-{1}}$ , respectively, for structures with an interelectrode distance of 30 $\mu \text{m}$ at an applied voltage of 10 V and exposure to radiation with a wavelength of 235 nm. The high values of the photoelectric characteristics were caused by the manifestation of an internal gain of the photoresponse due to the self-localization of holes in $\alpha $ -Ga2O3. The prospects of researches to develop UVC radiation detectors for wireless UVC communication were shown.