Electroluminescence Transition From Visible- to Ultraviolet-Dominant Mode in $\hbox{n-Mn}_{0.04}\hbox{Zn}_{0.96}\hbox{O/i-ZnGa}_{2}\hbox{O}_{4}\hbox{/} \hbox{n-GaN}$ Structure With Highly Ultraviolet Detection Performance

We report an n-Mn
_0.04
Zn
_0.96
O(MZO) /i-ZnGa
₂
O
₄
/ 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-ZnGa
₂
O
₄
interface 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.