STUDY OF INTERFACE ASYMMETRY IN INAS-GASB HETEROJUNCTIONS

We present reflection high energy electron diffraction, secondary ion mass spectroscopy, scanning tunneling microscopy and x-ray photoelectr on spectroscopy studies of the abruptness of InAs-GaSb interfaces. We find that the interface abruptness depends on growth order: InAs grown on GaSb is extended, while GaSb grown on InAs is more abrupt. We firs t present observations of the interfacial asymmetry, including measure ments of band alignments as a function of growth order. We then examin e more detailed studies of the InAs-GaSb interface to determine the me chanisms causing the extended interface. Our results show that Sb inco rporation into the InAs overlayer and As exchange for Sb in the GaSb u nderlayer are the most likely causes of the interfacial asymmetry. (C) 1995 American Vacuum Society.