Textured zinc oxide prepared by liquid phase deposition (LPD) method and its application in improvement of extraction efficiency for 650 nm resonant-cavity light-emitting diode (RCLED)

Abstract

In this article, we report on the textured zinc oxide (ZnO) prepared by liquid-phase deposition (LPD) method and apply it as a window layer of 650 nm resonant-cavity light-emitting diode to enhance the extraction efficiency. The treatment solution for LPD ZnO (LPD-ZnO) growth consists of ZnO powder saturated with hydrochloric acid (HCl) and hydrogen peroxide (H 2O 2). Temperature-controlled water bath system was used to maintain a constant temperature of 40 °C in LPD system. The experimental results indicate that the deposition rate was determined by the concentration of H 2O 2 and growth temperature, and the average roughness of LPD-ZnO is dominated by the concentrations of HCl. In order to perform the practicability of LPD-ZnO, the textured LPD-ZnO is used as a window layer of 650 nm AlGaInP/GaInP resonant-cavity light-emitting diode (RCLED) to enhance the light output power. In addition, the calculated results indicate that the optimum roughness for enhancing the light output power of RCLED is in the range of 80–100 nm, which are close to the experimental results. As compared to the conventional RCLED, the RCLED with textured LPD-ZnO, which has the optimum average roughness of 82 nm, performs a high light output power, a high external quantum efficiency, a narrow linewidth of electroluminescence spectrum and the same far-field angle.