Comparative study of the molecular beam epitaxial growth of InAs/GaSb superlattices on GaAs and GaSb substrates

Abstract

Short period type-II 10 ML InAs/10 ML GaSb superlattices epilayers (λcut-off = 5.4 μm) have been grown on near lattice matched GaSb (001) substrate and on lattice mismatched GaAs (001) substrate, by molecular beam epitaxy system. In the case of growing on GaAs substrate, GaSb buffer layer was grown in order to reduce the lattice mismatch of 7.5% between GaAs substrate and InAs/GaSb superlattices. X-ray diffraction characterization shows a good crystalline quality for both samples, with a full width at half maximum of 190 arcsec and 156 arcsec for the zeroth-order peak of the superlattice grown on GaAs and on GaSb substrate, respectively. The Nomarski microscopy revealed a shiny surface for both samples with a root main square of surface roughness of 9 nm and 11 nm on the case of growing on GaSb and GaAs substrate, respectively.