ABSTRACT
Semiconductor lasers emitting in the mid-infrared (IR) range have been intensely investigated recently. The interest in this type of lasers is aroused by outlooks for their extensive application to different branches of science and engineering. Analysis shows that the wave functions of carriers in the strained semiconductor heterostructures are to be calculated in the framework of the multiband approximation. It is accepted that in semiconductor heterostructures, as well as in bulk semiconductors, the intraband absorption by free carriers is weak because the absorption is possible when not only an electron and a photon but also some other particle. In type-I heterostructures the offsets of the conduction band and valence band at the interface between two materials have opposite directions. The chapter aims to develop a theory of a new non-threshold Auger recombination process in heterostructures with quantum wells. It is known that there is a considerable contribution to the threshold current of mid-IR lasers from leakage at high temperatures.
