Impact of Ex-Situ Heating on Carrier Kinetics in GaN/InGaN Based Green LEDs

Abstract

Self-heating has long been recognized as one of the major factors for performance deterioration of III-Nitride light emitting diodes (LEDs) during prolonged operation at high current. We have emulated the impact of self-heating on carrier kinetics in InGaN based green LED ( λ ∼ 516 nm at 1 mA forward current) using temperature dependent current vs voltage (T-I-V) characteristics in forward and reverse bias, where the temperature is varied from room temperature (25 °C) to 200 °C. Measured T-I-V characteristics are analyzed in detail so as to understand the dominant recombination mechanisms at different bias regimes. It is inferred that at high forward bias, Auger recombination plays a significant role during the ex-situ heating of LEDs. An exponential increase in reverse leakage current beyond a certain high temperature is attributed to the carriers attaining adequate thermal energy to escape from the active region.