Improved near-UV electroluminescence of ZnO nanorod array LEDs by coupling with a graphene plasmon layer

Cen Zhang,Weizhen Liu,Yichun Liu,Liu Yang,Chunliang Wang,Yue Qiu,Haiyang Xu

doi:10.1515/nanoph-2019-0228

Abstract

Abstract The development of short-wavelength light-emitting diodes (LEDs) with high emission efficiency, a fascinating research area, is still necessary because of great scientific interest and practical significance. Here, a graphene plasmon layer treated by oxygen plasma was employed into ZnO nanorod/p-GaN LEDs for a surface plasmon effect. The graphene-decorated heterojunction exhibited an approximately 4-fold improvement of ZnO ultraviolet (UV) electroluminescence (EL) intensity relative to a primitive p-n junction device. Time-resolved spectroscopy and temperature-dependent luminescence measurement indicated that the EL enhancement resulted from the coupling of ZnO excitons with graphene surface plasmons. The current research not only provides an opportunity to construct three-dimensional architecture from a vertical array of one-dimensional nanorods and a two-dimensional graphene layer, but also proposes an effective strategy to improve near-UV emission efficiency in various devices.

Highlights

A one-dimensional (1D) nanorod (NR) may be regarded as an ideal single crystal with superior photoelectric performance
A graphene plasmon layer treated by oxygen plasma was employed into ZnO nanorod/p-GaN lightemitting diodes (LEDs) for a surface plasmon effect
ZnO NR arrays were synthesized on the commercial p-GaN chip or the graphene/p-GaN substrate was imaged with a scanning electron microscope (SEM), as shown in Figure 2A and B

Summary

Introduction

A one-dimensional (1D) nanorod (NR) may be regarded as an ideal single crystal with superior photoelectric performance. Merging NRs into light-emitting diodes (LEDs) can effectively improve device performance [1,2,3,4]. ZnO is a third-generation semiconductor that is a potential building block for short-wavelength LEDs [5,6,7,8]. 1D ZnO NR arrays have exhibited excellent performance in the field of light-emitting devices [9,10,11,12,13,14,15,16]. An increased surface-to-volume ratio deteriorates the efficiency and stability of ZnO NR LEDs. an important challenge is to overcome these surface-mediated nonradiative and deep-level recombination channels in order to improve device performance

Methods

Results

Conclusion