Quantitative measurement of the influence of growth interruptions on the Sb distribution of GaSb/GaAs quantum wells by transmission electron microscopy

Abstract

We investigated the influence of growth interruptions on the morphology of molecular-beam epitaxy grown GaSb/GaAs multiquantum-well structures by transmission electron microscopy (TEM). Profiles of the chemical composition of the GaSb layers were deduced from high-resolution TEM images with the lattice fringe analysis method. We found clear indications of segregation of Sb in GaAs-on-GaSb for a sample grown with growth interruption before and after the growth of the quantum wells. Its efficiency R=0.78±0.03 was derived by fitting the measured composition profiles with the model of Muraki. Determination of the total amounts of deposited GaSb yields a higher amount of GaSb in a sample grown without interruption.