Electroluminescence enhancement of ZnO nanorods array determined by Au-nanoparticles position under external electric field

Abstract

In this work, n-ZnO nanorod arrays (NRA)/MgZnO/p-GaN heterojunction light-emitting diodes (LEDs) were successfully prepared. Au nanoparticles (NPs) were introduced in a simple and stable method to improve ultraviolet electroluminescence efficiency of the ZnO NRA. Although Au NPs are commonly seen as a factor to form localized surface plasmons resonance coupling effect in the visible region, ultraviolet electroluminescence enhancement of ZnO NRA was observed in this work. Importantly, the enhancement performance can be dominated by the position of Au NPs relative to ZnO nanorods driven by the external electric field. Au NPs located at the top of ZnO nanorods promise the additional exciton relaxation channels. As a result, the ZnO ultraviolet near-band-edge (NBE) emission efficiency is improved by 4 times in the Au NPs modified devices. This enhancement process provides a new approach to design efficient UV ZnO-based LEDs.