Mechanism of the temperature sensitivity of mid-infrared GaSb-based semiconductor lasers

The sources of temperature sensitivity of the threshold current in type-I and type-II mid-infrared semiconductor lasers are investigated. Measurements of the interband optical absorption allow direct comparison of the optical matrix elements in laser structures with type-I and type-II band alignments and prove that the difference in the optical matrix elements is insignificant for these two groups of structures. We show that thermally-induced hole escape from the active quantum wells strongly deteriorates the optical emission in both type heterostructures. Experiments show that the temperature decay of PL is generally stronger for type-II samples.