Study of InAs/InAsSb type-II superlattices using high-resolution x-ray diffraction and cross-sectional electron microscopy

InAs/InAs1−xSbx type-II superlattices (SLs) have been grown on GaSb (100) substrates using molecular beam epitaxy with different Sb/In and As/In flux ratios and growth temperatures ranging from 400 °C to 450 °C. The change in SL microstructure as a result of adjusting the growth conditions has been comprehensively studied. High-resolution x-ray diffraction reveals increase in Sb composition as either growth temperature or the ratio of As/Sb is decreased. Cross-sectional electron micrographs show excellent crystallinity, particularly for those samples grown close to the strain-balanced condition at lower temperatures and those with higher Sb/As flux ratios.