Light-Emitting Diode Degradation and Low-Frequency Noise Characteristics

Comprehensive investigation of phosphide-based red and nitride-based blue light-emitting diodes characteristics and physical processes that take place in device structure during aging has been carried out. Analysis of noise characteristics (the emitting-light power and the LED voltage fluctuations, also their cross-correlation factor) shows that investigated LEDs degradation is caused by defects that lead to the leakage current and non-radiating recombination increase in the active region or its interfaces. Appearance of the defects first of all manifests in noise characteristics: intensive and strongly correlated $1//f^{α}$ type optical and electrical fluctuations come out.