Interface roughness and asymmetry in InAs/GaSb superlattices studied by scanning tunneling microscopy

InAs/GaSb superlattices are studied in cross section by scanning tunneling microscopy and spectroscopy. Electron subbands in 42 thick InAs layers are clearly resolved in the spectra. Roughness of the superlattice interfaces is quantitatively measured. Interfaces of InAs grown on GaSb are found to be rougher, with different electronic properties, than those of GaSb on InAs, indicating some intermixing in the former case. © 1994 The American Physical Society.