High efficiency mid-infrared interband cascade light emitting diodes with immersion lens

Abstract

We report on ten-stage interband cascade light-emitting diodes (ICLEDs) using an InAs/GaAsSb superlattices active region with a peak emission wavelength of 4.9 μm at the temperature of 80 K. The ICLED devices integrated with an immersion lens achieve a wall-plug quantum efficiency of 6.6% and an emittance of 1.9 W/cm2 under 80 K and 7.7 A/cm2, which is seven times larger than the basic device without the immersion lens. We present a detailed analysis of the recombination rates and their relationship with the quantum efficiency. The Shockley–Read–Hall and Auger recombination rates were measured using carrier-density dependent time-resolved photoluminescence spectra. The band structure of InAs/GaAsSb superlattices is calculated to study their relationship with the Auger recombination rates.