Growth of InAs0.32Sb0.68 on GaAs using a thin GaInSb buffer and strain superlattice layers

We report on the growth of an InAs0.32Sb0.68 layer on (001) GaAs substrates. The lattice mismatch strain between the InAs0.32Sb0.68 layer and the GaAs substrate was accommodated using a thin 50–100 nm Ga0.35In0.65Sb buffer with interfacial misfit (IMF) dislocations. The epitaxial structures were characterized using transmission electron microscopy and x-ray diffraction analysis. The threading dislocation density in the InAs0.32Sb0.68 layer was reduced successfully to ∼1 × 108 cm−2 using the combination of a Ga0.35In0.65Sb IMF buffer and InSb/Ga0.35In0.65Sb superlattice layers. Compared to GaSb/GaAs and InSb/GaAs interfaces, a significantly higher threading dislocation density (>1011 cm−2) was observed at the Ga0.35In0.65Sb/GaAs interface. Detailed analysis suggests that high threading dislocation density in the Ga0.35In0.65Sb IMF buffer could be due to the non-uniform microscopic distribution of indium and gallium atoms. This work is beneficial to the scientific community in the growth of the InAs0.32Sb0.68 material as it provides a novel approach to prepare a platform for the growth of the InAs0.32Sb0.68 material, which does not have a suitable lattice-matched substrate, on the widely available GaAs substrate.