THEORETICAL PERFORMANCE LIMITS OF 2.1-4.1 MU-M INAS/INGASB, HGCDTE, AND INGAASSB LASERS

Ideal threshold current densities of 2.1-4.1 mu m IR lasers are calculated for active layers composed of InAs/InGaSb superlattices, InGaAsSb quantum well quaternaries, InAsSb bulk ternaries, and HgCdTe superlattices. The fully K-dependent band structure and momentum matrix elements, obtained from a superlattice K . p calculation, are used to calculate the limiting Auger and radiative recombination rates and the threshold current density. InGaAsSb quantum wells and InAs/InGaSb superlattices are found to be more promising laser candidates than HgCdTe superlattices and InAsSb bulk ternaries. The calculated threshold current densities of InAs/InGaSb superlattices are similar to those of InGaAsSb active layers at 2.1 mu m, but are significantly lower at longer wavelengths. Comparison with experiment indicates that the threshold current densities of InGaAsSb-based devices are about three times greater than those calculated for 25 cm(-1) gain. The threshold current densities of present InAs/InGaSb superlattices are about 100 times above their theoretical limit. (C) 1995 American Institute of Physics.