Imaging research based on 6×6 CuGa2O4 microwire photodetectors array

The band gap of P-type wide bandgap semiconductor CuGa2O4 is approximately 4.4 eV, and its absorption edge is around 280 nm, making it a potential ideal material for fabricating full-band solar-blind ultraviolet photodetectors. In this study, centimeter-sized CuGa2O4 microwires were fabricated on a sapphire substrate using the chemical vapor deposition (CVD) method. The length of microwires could reach up to 0.8 cm, and the diameter was approximately 35 μm. The metal-semiconductor-metal (MSM) ultraviolet photodetector was fabricated based on a single CuGa2O4 microwire. The device exhibits excellent photoresponse performance under 280 nm UV illumination, with a light-dark current ratio of up to 1.0×107, as well as high responsivity of 254.5 A/W and a specific detectivity of 8.32×1015 Jones. Furthermore, a flexible 6×6 UV photodetector array was fabricated by transferring 36 CuGa2O4 microwires onto a polyethylene terephthalate substrate (PET), and systematically investigated its imaging performance. The array demonstrated uniform responsivity, with a maximum standard deviation of about 0.84%. At different bending angles (0°, 15°, 30°, and 45°), the array maintained stable imaging and could clearly recognize the letters “L”, “N”, “N”, and “U”. In addition, after 200 bending cycle tests at 30°, both the photocurrent and dark current showed no significant degradation. These results demonstrate a feasible approach for developing flexible full-band solar-blind ultraviolet photodetector arrays and demonstrate the potential application of CuGa2O4 materials in wearable UV monitoring and imaging fields.