Bifunctional Photovoltaic and Violet Electroluminescent Devices Based on $n\hbox{-}{\rm ZnO}/n\hbox{-}{\rm GaN}$ Heterojunctions

Abstract

An n-ZnO/n-GaN heterojunction has been fabricated by depositing n-ZnO film onto an n-GaN/sapphire substrate. A bifunctional photovoltaic (PV) and violet electroluminescent device based on n-ZnO/n-GaN heterojunction was obtained. As a PV cell, the device exhibits a clear PV behavior under AM 1.5 G simulated illumination (100 mW cm −2 ). The power conversion efficiency is 0.57%. The open-circuit voltage and the short-circuit current are 1.12 V and 12.3 µA, respectively. As a light emitting diode, the device exhibits a violet emission peak centered at ∼433 nm under a bias voltage, and the apparent violet light is easily observed with the naked eyes. The mechanism for the dual function heterojunction device has been discussed.

Nanointerlayer Induced Electroluminescence Transition from Ultraviolet- to Red-Dominant Mode for n-Mn:ZnO/N-GaN Heterojunction

“…However, the reports about this red emission are seldom in ZnO-based devices. In our previous works, we have reported ZnO-based heterojunction LEDs with different structures, − all of which showed limited rectification ratios and very strong UV electroluminescence (EL) and quite weak EL in visible region. , And Li, et al reported n-ZnO/n-GaN Heterojunction LEDs, which showed a clear photovoltaic behavior with a power conversion efficiency of 0.57% and a violet emission peak centered at ∼433 nm. Huang, et al reported an annealed n-ZnO/n-GaN structure and it showed a sharp UV emission centered at 367 nm and a broad orange emission centered at 640 nm under forward and reverse biases, respectively.…”