Electroluminescence Transition From Visible- to Ultraviolet-Dominant Mode in n-Mn0.04Zn0.96O/i-ZnGa₂O₄/ n-GaN Structure With Highly Ultraviolet Detection Performance

We report an n-Mn0.04Zn0.96O(MZO) /i-ZnGa2O4/ n-GaN structure both as a light-emitting diode and as an ultraviolet (UV) photodetector at forward and reverse biases, respectively. The n-MZO films were prepared on n-GaN coated sapphire substrates, followed by postdeposition thermal annealing treatment at 700°C, and an i-ZnGa2O4interface layer was formed at the MZO/GaN interface after the annealing treatment. We found that the electroluminescence characteristics showed a transition from visible- to UV-dominant mode when the deposition temperature of the MZO film is from 100°C to 300°C. For the UV detection performance, the devices based on the low-temperature deposition (100°C) of the MZO film showed the lowest dark current and the biggest ratio of photocurrent to dark current with a selectivity detectivity for 365 nm around light.