Influence of different insulating polymers on the performance of ZnO nanorod based LEDs

Abstract

ZnO is a promising material for optoelectronic devices because of its wide bandgap and large exciton binding energy. However, majority of studies of ZnO nanostructures have been focusing on the study of their optical and structural properties. For device applications of ZnO, other factors besides ZnO material quality also play a significant role. For example, a typical ZnO nanorod based light emitting diode (LED) contains a polymer insulating layer and a top contact. The device performance is dependent on the insulating layer and top contact quality. In this work, the effect of different insulating polymers on the performance of p-GaN/n-ZnO LED was investigated. The structure of LED was: Au/ Ni/p-GaN/ZnO nanorods/insulating polymers/Ag. The ZnO nanorods were fabricated by hydrothermal method, and the length of the nanorods was 250 nm. In this work, we investigated absorption spectra, electroluminescence (EL) properties, and I-V curves to characterize the performance of the devices fabricated using spin-on glass (SOG), poly(vinylalcohol) (PVA), polymethyl methacrylate (PMMA) and polystyrene (PS) as insulating layers. Finally, the comparison of the performance of the devices with different polymers was discussed.