Performance study of full-band solar-blind UV photodetector based on CuGa<sub>2</sub>O<sub>4</sub> thin films

<p indent="0mm">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 <sc>4.4 eV.</sc> 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 <sc>280 nm</sc> 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 <sc>10 V</sc> bias. The responsivity (<italic>R</italic>), external quantum efficiency (EQE), and specific detectivity (<italic>D</italic>^*) of the device are <sc>4.29 A W⁻¹,</sc> 1899.86%, and 1.31×10¹⁴ Jones, respectively, at light intensity <sc>11 μW cm⁻².</sc> The results of this study provide a novel approach for the development and research of the full-band solar-blind UV photodetector.