Optical and electrical noise in RGB LEDs in the mHz to kHz frequency band

Abstract

Defects in the active region of light-emitting diodes (LEDs) have a strong correlation with low-frequency electrical and, consequently, optical fluctuations of the light source. We investigate these two types of noise in red, blue, and green commercially available LEDs using a superposition model of stationary (thermal and shot noise) and excess noise (flicker and generation-recombination noise). The dependence of the degree of the low-frequency component on the supply current and the LED material was obtained. The occurrence of Lorentzinana-type spectrum at high currents for blue and green LEDs is also observed.