Self-powered UVC detectors based on α-Ga<sub>2</sub>O<sub>3</sub> with enchanted speed performance
А. V. Аlmaev, A. V. Tsymbalov, Bogdan O. Kushnarev, В. И. Николаев, А. И. Печников, M. P. Scheglov, Àndrei Chikiryaka
Abstract
Abstract Detectors were developed for detecting irradiation in the short-wavelength ultraviolet (UVC) interval using high-quality single-crystalline α -Ga 2 O 3 films with Pt interdigital contacts. The films of α -Ga 2 O 3 were grown on planar sapphire substrates with c -plane orientation using halide vapor phase epitaxy. The spectral dependencies of the photo to dark current ratio, responsivity, external quantum efficiency and detectivity of the structures were investigated in the wavelength interval of 200−370 nm. The maximum of photo to dark current ratio, responsivity, external quantum efficiency, and detectivity of the structures were 1.16 × 10 4 arb. un., 30.6 A/W, 1.65 × 10 4 %, and 6.95 × 10 15 Hz 0.5 ·cm/W at a wavelength of 230 nm and an applied voltage of 1 V. The high values of photoelectric properties were due to the internal enhancement of the photoresponse associated with strong hole trapping. The α -Ga 2 O 3 film-based UVC detectors can function in self-powered operation mode due to the built-in electric field at the Pt/ α -Ga 2 O 3 interfaces. At a wavelength of 254 nm and zero applied voltage, the structures exhibit a responsivity of 0.13 mA/W and an external quantum efficiency of 6.2 × 10 −2 %. The UVC detectors based on the α -Ga 2 O 3 films demonstrate high-speed performance with a rise time of 18 ms in self-powered mode.