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 usin g low-pressure metal organic vapour-phase epitaxy. We characterized the str uctural and optical properties of strained and strain-compensated superlatt ices using X-ray diffractometry and low-temperature photoluminescence (PL) measurements. For samples of ten periods of 10 nm InAsSb wells and 50 nm In As barriers, a maximum Sb content of 5.7% is possible without causing strai n-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 wi th unstrained InPSb cladding layers. Temperature-resolved PL measurements s how that the peak decreases rapidly with increasing temperature. The compen sation 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 sligh tly better properties. Significant improvement was achieved by homogeneous InAsP barriers with a P content between 3% and 10%. Strain-compensated InAs Sb/InAsP superlattices were fabricated up to an antimony content of 17% wit hout degradation. Samples containing 24% Sb in the wells exhibited PL emiss ion energies below the band gap of InSb. (C) 1998 Elsevier Science B.V. All rights reserved.