ZnO nanorod/GaN light-emitting diodes: The origin of yellow and violet emission bands under reverse and forward bias
Open Access
- 1 November 2011
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 110 (9), 094513
- https://doi.org/10.1063/1.3653835
Abstract
ZnOnanorods have been prepared by electrodeposition under identical conditions on various p-GaN-based thin film structures. The devices exhibited lighting up under both forward and reverse biases, but the turn-on voltage and the emission color were strongly dependent on the p-GaN-based structure used. The origin of different luminescence peaks under forward and reverse bias has been studied by comparing the devices with and without ZnO and by photoluminescence and cathodoluminescence spectroscopy. We found that both yellow-orange emission under reverse bias and violet emission under forward bias, which are commonly attributed to ZnO, actually originate from the p-GaN substrate and/or surface/interface defects. While the absolute brightness of devices without InGaN multiple quantum wells was low, high brightness with luminance exceeding 10 000 cd/m2 and tunable emission (from orange at 2.1 V to blue at 2.7 V, with nearly white emission with Commission internationale de l’éclairage (CIE) coordinates (0.30, 0.31) achieved at 2.5 V) was obtained for different devices containing InGaN multiple quantum wells.Keywords
This publication has 48 references indexed in Scilit:
- Low‐Voltage UV‐Electroluminescence from ZnO‐Nanowire Array/p‐GaN Light‐Emitting DiodesAdvanced Materials, 2010
- Structure and Ultraviolet Electroluminescence of $n \hbox{-ZnO/SiO}_{2}\hbox{-ZnO}$ Nanocomposite/$p$ -GaN Heterostructure Light-Emitting DiodesIEEE Transactions on Electron Devices, 2010
- Mechanism of the GaN LED efficiency falloff with increasing currentSemiconductors, 2010
- White Electroluminescence Using ZnO Nanotubes/GaN Heterostructure Light-Emitting DiodeNanoscale Research Letters, 2010
- The Influence of the ZnO Seed Layer on the ZnO Nanorod/GaN LEDsJournal of the Electrochemical Society, 2010
- Ultraviolet electroluminescence from ZnO∕p-Si heterojunctionsJournal of Applied Physics, 2007
- Determination of carrier density of ZnO nanowires by electrochemical techniquesApplied Physics Letters, 2006
- Electroluminescence at 375nm from a ZnO∕GaN:Mg∕c-Al2O3 heterojunction light emitting diodeApplied Physics Letters, 2006
- Tunneling radiative recombination in p-n heterostructures based on gallium nitride and other AIIIBV semiconductor compoundsJournal of Experimental and Theoretical Physics, 2003
- Optically and thermally detected deep levels in n-type Schottky and p+-n GaN diodesApplied Physics Letters, 2000