Kinetic model for degradation of light-emitting diodes

Abstract

We present a kinetic model for the optical output degradation of light-emitting diodes based on the carrier-recombination enhanced defect motion. Our model leads to analytical solutions and universal curves for the optical output power and the defect density as a function of the normalized aging time with the initial quantum efficiency as the determining parameter. The theoretical results explain very well the time dependence of the II-VI light-emitting diodes under constant current aging condition. The faster aging rate with increasing bias current or temperature is also investigated both experimentally and theoretically, resulting in a very good agreement. Our model provides a quantitative description of the light-emitting diode aging characteristics for compound semiconductors in the presence of electron-hole recombination-enhanced defect generation.