ABSTRACT
This chapter reviews the growth of GainSb/InAs superlattices and AlSb/InAs superlattices employed as clads, and summarizes the intrinsic and extrinsic properties salient to diode lasers. Intrinsic properties favor GainSb/InAs superlattices over the competition; devices based on the structures are projected to have the best mid-wave infrared performance if brought to maturity. Interest in GainSb/InAs-based devices stems both from favorable intrinsic properties and from practical advantages associated with molecular beam epitaxy (MBE) growth of superlattices. Auger processes allow electron-hole pairs to recombine without emitting photons, instead conserving energy and momentum by promoting a third carrier to a higher-lying state. MBE growth of lasers based on superlattices appears to be easier and more reproducible than for devices based on alloys containing more than one group-V species. Laser design has taken account of optical confinement factors, quantifying the waveguiding properties of particular active and cladding layer combinations to analyze single mode losses for epilayer thicknesses within the range readily grown by MBE.
