Low-threshold long-wave lasers ( lambda =3.0-3.6 mu m) based on III-V alloys

The authors present data on low-threshold (Jth<100 A cm-2) lasers for the 3-4 mu m range based on InGaAsSb/InAsSbP double heterostructures with compositions close to InAs. The basic features of long-wave lasers were studied in samples with an n-InAs active region. The optimal parameters and the free carrier absorption coefficient in n-InAs were derived from the dependence of the threshold current density on the resonator length, active layer thickness and doping level. To explain the variation of the emission line within 393-410 meV (77 K), three possibilities are considered: band-to-band and band-to-acceptor transitions as well as interface recombination in type II InAs/InAsSbP heterojunctions.