O. G. Ershov

Suppression of Auger recombination in the diode lasers based on type II InAsSb/InAsSbP and InAs/GaInAsSb heterostructures

Comparative study of threshold current temperature dependence, differential quantum efficiency and light polarization was performed for type I and type II InAsSb/InAsSbP heterostructures as well as for tunneling- injection GaInAsSb/InGaAsSb laser based on this type II broken-gap heterojunction. Experimental evidence of non- radiative Auger-recombination suppression in type II InAsSb/InAsSbP heterolasers with high band-offset ratio (Delta) Ev/(Delta) Ec equals 3.4 was obtained. Reduction of temperature dependence of the threshold current was demonstrated for both kinds of type II lasers. Maximum operation temperature and characteristic temperature T equals 203 K with T0 equals 40 K and T equals 195 K with T0 equals 47 K were achieved for type II InAsSb/InAsSbP and tunneling- injection p-GaInAsSb/n-InGaAsSb lasers, respectively.

3.2 AND 3.8 μm Emission and Lasing in AlGaAsSb/InGaAsSb Double Heterostructures with Asymmetric Band Offset Confinements

We report the first observations of electroluminescence (EL) and lasing in laser structures with high Al-content (x=0.64, Eg=1.474 eV) cladding layers and a narrow-gap InGaAsSb active layer (Eg=0.326 eV at T=77K). The structures are LPE-grown lattice-matched to GaSb substrate. Band energy diagrams of the laser structures had strongly asymmetric band offsets. The heterojunction between high Al-content layer and InGaAsSb narrow-gap active layer has a type II broken-gap alignment at 300K. In this laser structure spontaneous emission was obtained at λ=3.8μm at T=77K and λ=4.25 μm at T=300K. Full width at half maximum (FWHM) of emission band was 34 meV. Emission intensity decreased by a factor of 30 from T=77K to 300K. Lasing with single dominant mode was achieved at λ=3.774 μm (T=80K) in pulsed mode. Threshold current as low as 60 mA and characteristic temperature T 0 =26K were obtained at T=80–120K.