Strain and interfacial bond type effects on structural quality of InAs/Ga(As,Sb) superlattices grown on InAs substrates

A series of InAs/Ga(As,Sb) superlattices were grown on InAs substrates by molecular beam epitaxy. The samples were grown in a manner that allowed the nature of the interfacial bonds (either GaAs or In(As,Sb)-like) to be controlled). In some of the samples the bond type-related strain was accommodated by adjusting the Sb mole fraction to nearly lattice match the superlattice to the substrate regardless of bond configuration. High-resolution X-ray diffraction measurements and transmission electron microscopy images reveal that samples grown with In(As,Sb)-like bonds on top of the InAs layers exhibit superior structural quality. Samples with GaAs-like bonds at both interfaces are far inferior to the others.