Improved color rendering of phosphor-converted white light-emitting diodes with dual-blue active layers and n-type
Qi-Rong Yan1, Yong Zhang, Shu-Ti Li
1Institute of Optoelectronic Materials and Technology, South China Normal University, Tianhe District, Guangzhou 510631, China.
Abstract:
An InGaN/GaN blue light-emitting diode (LED) structure and an InGaN/GaN blue-violet LED structure were grown sequentially on the same sapphire substrate by metal-organic chemical vapor deposition. It was found that the insertion of an n-type AlGaN layer below the dual blue-emitting active layers showed better spectral stability at the different driving current relative to the traditional p-type AlGaN electron-blocking layer. In addition, color rendering index of a Y3Al5O12:Ce3+ phosphor-converted white LED based on a dual blue-emitting chip with n-type AlGaN reached 91 at 20 mA, and Commission Internationale de L'Eclairage coordinates almost remained at the same point from 5 to 60 mA.
