Low-pressure metal organic vapour-phase epitaxy and characterization of strained InAs(P)/InAsSb superlattices for infrared emitters

Strained InAsSb-containing superlattices were grown on InAs substrates using low-pressure metal organic vapour-phase epitaxy. We characterized the structural and optical properties of strained and strain-compensated superlattices using X-ray diffractometry and low-temperature photoluminescence (PL) measurements. For samples of ten periods of 10 nm InAsSb wells and 50 nm InAs barriers, a maximum Sb content of 5.7% is possible without causing strain-induced degradation of the layer stack. This value could be increased to 12% by embedding the superlattice into the undoped region of a PIN-diode with unstrained InPSb cladding layers. Temperature-resolved PL measurements show that the peak decreases rapidly with increasing temperature. The compensation for the tensile strain of the InAsSb wells by small 2.5 nm thick Gao(0.25)In(0.75)As layers within the middle of the InAs barriers led to slightly better properties. Significant improvement was achieved by homogeneous InAsP barriers with a P content between 3% and 10%. Strain-compensated InAsSb/InAsP superlattices were fabricated up to an antimony content of 17% without degradation. Samples containing 24% Sb in the wells exhibited PL emission energies below the band gap of InSb. (C) 1998 Elsevier Science B.V. All rights reserved.