Optical characterization and room temperature lifetime measurements of high quality MBE-grown InAsSb on GaSb

InAs 0.91 Sb 0.09 lattice matched to a GaSb substrate by molecular beam epitaxy (MBE) is characterized by photoluminescence and photoconductivity measurements. Absorption, photoluminescence and spectrally resolved dc photoconductivity measurements lead to a band gap expression for InAs 1- x Sb x , as a function of the Sb content x , where 0.06< x <0.12 and the material is nearly lattice matched to GaSb. The expression is in good agreement with recent results focusing on this range of Sb content, but deviates significantly from the one known from the literature and covering the entire Sb composition range. The carrier lifetime was measured by stationary and time resolved photoconductivity with an excitation source at 3.39 µm. We report Shockley-Read limited lifetimes as long as 200 ns, which indicate the high quality of the material. The accuracy and consistency of these optical characterization techniques allow a reliable comparison of samples and provide a guide for the optimization of growth parameters.