Transmission electron microscopy and transmission electron diffraction structural studies of heteroepitaxial InAsySb1−y molecular-beam epitaxial layers

Publisher Website
Google Scholar
Abstract
Molecular‐beam epitaxy InAsySb1−y layers were grown at temperatures ranging from 295 to 470 °C across the full composition range. Transmission electron microscopy and transmission electron diffraction (TED) examinations showed that for layers grown at and below 400 °C with nominal compositions 0.4<y0.38Sb0.62 and InAs0.72Sb0.28. The plates were larger and more regular along the [1̄10] direction than the [110] direction. As the growth temperature increased from 295 to 400 °C, for layers of nominal composition InAs0.5Sb0.5, the plate length increased from 0.1 to 2.0 μm and the plate thickness from 10 to 50 nm. Crystallographic defects were present in the layers and their occurrence was different in the phase‐separated and non‐phase‐separated layers. The plates formed spontaneously at the growing surface and were stable during subsequent annealing at 350 and 370 °C. It is suggested that they arise due to the presence of a miscibility gap at these growth temperatures. We have termed these spontaneously grown plate structures ‘‘natural’’ strained layer superlattices.