Noise characteristics and reliability of high power white light emitting diodes based on nitrides

Abstract

High power white light emission diode reliability and aging processes have been investigated. Optical, electrical and noise characteristics have been carried out for initial devices and during their aging. Analysis of noise characteristics help revealing of light emission diode aging processes and reliability problems. It is found that optical and electrical noise spectra changes reflect light emission diode aging. Noise characteristics, especially correlation factor between optical and electrical fluctuations, and current-voltage characteristics at low bias reveal physical processes that take place during investigated device aging and rapid its degradation. It is shown that reason of high power light emission diode degradation is related with defects presence in the device structure. Additional defects appear during LED operation and lead to the leakage current and non-radiative recombination increase.