Performance study of full-band solar-blind UV photodetector based on CuGa₂O₄ thin films

The CuGa2O4 with a spinel structure is a p-type semiconductor material, exhibiting excellent physical and chemical stability. Its bandgap is located at the low-energy edge of the solar-blind band, making it a novel material for solar-blind band detection. For this purpose, high quality CuGa2O4 films were grown on a sapphire substrate using chemical vapor deposition (CVD) method by studying the mass ratio of different reaction sources (CuO and Ga2O3). It was found that when the mass ratio of CuO powder to Ga2O3 powder is 1:1, CuGa2O4 thin films with a (111) preferred orientation can be prepared, and the optical band gap is approximately 4.4 eV. A photoconductive solar-blind UV photodetector was fabricated based on the CuGa2O4 thin film, and its UV detection performance was investigated. The results show that the UV detector exhibits excellent photoresponse to 280 nm UV light, indicating that the device belongs to the full-band solar blind UV photodetector. The dark current value of the device is 0.2 nA, and its light-dark current ratio can reach 5.78×104 under 10 V bias. The responsivity (R), external quantum efficiency (EQE), and specific detectivity (D*) of the device are 4.29 A W−1, 1899.86%, and 1.31×1014 Jones, respectively, at light intensity 11 μW cm−2. The results of this study provide a novel approach for the development and research of the full-band solar-blind UV photodetector.