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

摘要

We report an $hbox{n-Mn}_{0.04}hbox{Zn}_{0.96}hbox{O}!(hbox{MZO})! hbox{/}hbox{i-ZnGa}_{2}hbox{O}_{4}!hbox{/}breakhbox{n-GaN}$ 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 $^{circ}hbox{C}$, and an $hbox{i-ZnGa}_{2}hbox{O}_{4}$ 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 $^{ circ}hbox{C}$ to 300 $^{circ}hbox{C}$. For the UV detection performance, the devices based on the low-temperature deposition (100 $^{circ}hbox{C}$) 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.