The influence of ZnO seed layers on n-ZnO nanostructure/p-GaN LEDs

摘要

Light-emitting diodes (LEDs) were formed by hydrothermally growing n-ZnO nanostructures on p-GaN with or without seed layers. The performance of the fabricated LEDs was studied. The seed layers not only have a great influence on the morphology and density of the ZnO nanostructures but also determine the lighting bias and emitting mechanism. The LEDs without seed layers and with sputtered seed layers exhibit light emission only under reverse bias, which is believed due to the GaN buffer layer/p-GaN p-n junction. The LEDs with sol-gel seed layers exhibit light emission under both forward and reverse biases. With the increase of the forward bias, the LEDs first demonstrate a red electroluminescence emission coming from the sol-gel seed layers and then demonstrate an orange emission coming from the ZnO nanorods. The sol-gel seed layer and the interface play a very important role in the electroluminescence.