Observation of 394 nm electroluminescence from low-temperature sputtered n-ZnO/SiO2 thin films on top of the p-GaN heterostructure

The authors report on the 394 nm UV light emission from low-temperature sputtered n-ZnO/SiO2 thin films on top of the p-GaN heterostructure. They compare samples with and without a SiO2 current blocking layer. With a SiO2 layer, electroluminescence spectrum shows a sharp emission peak at 394 nm, which is attributed to the recombination of accumulated carriers between n-ZnO/SiO2 and p-GaN/SiO2 junctions. As for the sample without a SiO2 layer, a broadband ranging from 400 to 800 nm is observed, which is due to Mg+ deep-level transition in the GaN along with defects in the ZnO layers. (c) 2007 American Institute of Physics.