Mid-infrared interband cascade light-emitting diodes with InAs/GaAsSb superlattices on InAs substrates

In this work, we report interband cascade light emitting diodes (ICLEDs) based on InAs/GaAsSb superlattices emitting around 4.5 μm The ICLED structures were grown on InAs substrates by molecular beam epitaxy, which were composed of InAs/GaAsSb superlattice emitters, InAs/AlAsSb multi-quantum well (MQW) injection regions, and the GaAsSb/AlAsSb MQW tunneling regions. Both 5-stage and 2-stage ICLEDs were fabricated. The devices exhibited high output power, low series resistance and high wall-plug efficiency (WPE). At room temperature, radiances of 0.36 W/cm² sr and 0.19 W/cm² sr were achieved from the 5-stage and 2-stage ICLEDs respectively. At 80 K, the output power from the 5-stage ICLED reached 3.56 mW with 350 mA injection current, resulting in a WPE of around 0.5%. The efficiency was largely maintained with increasing injection. The thermal quenching of these ICLEDs from 20 K to 300 K was also significantly less than other types of devices emitting at similar wavelengths. These results demonstrate that ICLEDs have great potential for mid-infrared light emitting diode applications requiring large output power and high wall-plug efficiency.