Color Conversion of GaN-Based Micro Light-Emitting Diodes Using Quantum Dots

Abstract

Using CdSe/ZnS quantum dots (QDs) excited by the blue light emission of GaN-based micro light-emitting diodes (LEDs), quasi-monochromatic red light sources with emission wavelength of 625 nm were obtained. In order to enhance the blue light emission of GaN-based LEDs for further excitation of QDs, distributed/hybrid Bragg reflectors and zinc oxide (ZnO) nanorod array were, respectively, introduced to the top/bottom and top sides of GaN-based micro LEDs. The presence of ZnO nanorod array helps to channel the blue light to pump the CdSe/ZnS QDs for enhancing the red light emission. The electroluminescence of micro QDs-LEDs with reflectors and ZnO nanorod array was increased by 57.4% compared with the micro QDs-LEDs alone. The international commission on illumination chromaticity coordinate of the micro QDs-LEDs with reflectors and ZnO nanorod array was very close to the red light emission at (0.59, 0.26).