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InAsSb/InAs type II strain balanced superlattices lattice matched to GaSb have recently been proposed as an alternative to InAs/(In)GaSb short period superlattices for mid- to long infrared photodetectors. Photoluminescence data at 4 K of OMVPE grown InAsSb (multi-) quantum wells in an InAs matrix on InAs and GaSb substrates is presented for Sb compositions between 4% and 27%. The measured transition energies are simulated with a self-consistent Poisson and Schroedinger equation solver that includes strain and band-offsets. The fitted parameters are then used to predict the type II transition energies of InAsSb/InAs strain balanced superlattice absorber stacks at 77 K for different compositions and periods. The optical matrix element was calculated and compared with InAs/(In)GaSb superlattices. The InAsSb/InAs structures can be designed with higher or equal matrix elements for longer periods. Finally, the initial optical response data of an unoptimized strain balanced InAs0.79Sb0.21/InAs detector with a 40 nm period are shown. Its cutoff wavelength is 0.15 eV (8.5 μm), in good agreement with the predicted type II transition energy of 0.17 eV.

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The III-V metastable aHoy lnP 1 _ xSbx has been grown for the first time with compositions wen inside the miscibiHty gap. Despite the large miscibility gap at the growth temperatures of 480-600 o e, epilayers with compositions covering the entire range from x = 0 to 1.0 have been grown successfully by organometallic vapor-phase epitaxy at atmospheric pressure using the reactants trimethylindium, trimethylantimony, and phosphine. The lO-K energy band gap as a function of composition was determined from photoluminescence measurements combined with x-ray diffraction and electron microprobe analysis. The bowing parameter for the bandgap energy of the InP j _ xSbx was estimated to be 1,9 ± 0.1 eV. The lattice dynamics have been studied using Raman spectroscopy in the frequency range from 150 to 400 cm-I . Long wavelength optical phonons display a "two-mode" behavior throughout the entire composition range. The InP-like longitudinal-optical and transverse-optical modes shift to lower frequency with increasing Sb concentration.

The first investigation of the lattice dynamics of the ternary alloy InAs1−xSbx has been made using Raman scattering. The InAs1−xSbx epilayers were grown by organometallic vapor phase epitaxy on (100) InAs and InSb substrates over the entire composition range. The spectra in the optical phonon frequency range show only one set of longitudinal- and transverse-optical (LO,TO) modes, which vary continuously with composition for x≤0.6, and two sets of LO modes for x>0.6. Both disorder-activated acoustic and optical phonon modes also appear.