A cross-sectional scanning tunnelling microscopic investigation was made of the atomic-scale morphology and composition of the heterojunction. A new so-called white-noise component was found in the wave-vector dependent roughness spectrum under typical epitaxial growth conditions. This phenomenon was attributed to random substitutional defects, at the interface, whose concentration exceeded that due to bulk incorporation. It was proposed that these defects originated from thermodynamically favorable, but incomplete, replacement of As by Sb at the InAs surface during anion exchange.

Microstructure of a GaSb-on-InAs heterojunction examined using cross-sectional scanning tunnelling microscopy J.Harper, M.Weimer, D.Zhang, C.H.Lin, S.S.Pei: Applied Physics Letters, 1998, 73[19], 2805-7