Theoretical Analysis of Gain in Compressive Strained Quantum Well InAlAsSb/GaSb Structures for 3-4 μm Lasers

Mid-infrared laser diodes are important sources for laser radar systems, molecular spectroscopy, and remote sensing of pollution and gases. InGaSbAs/GaAlSbAs lasers emitting at 2 μm are explored in detail since first room-temperature (RT) lasers [1-3] were demonstrated. However, a breakthrough in 3-4 μm lasers was made only recently [4-6]. Long wavelength lasers exhibit low characteristic temperature (T0 ≤ 30 K [6]), preventing them from operation at RT. One of the possible reasons of high threshold current at RT is Auger-recombination, which is proportional to cube of carrier density. Therefore, for long-wavelength lasers, it is especially important to decrease the carrier density at threshold.