InAs/GaSb superlattices with different interfaces studied by resonant raman scattering ans ellipsometry

In As/GaSb short-period superlattices (SLs) with either InSs- or GaAs-like interfaces were studied by Raman scattering and spectral ellipsometry. Roomtemperature ellipsometrie measurements show spectral features in the dielectric function due to the E1 and E1 + Delta1 interband transitions of GaSb and InAs. For SLs with small InAs layer thicknesses (4ML InAs/10ML GaSb) the critical point energies are found to depend on the type on interfacial bonding. The efficiency for Raman scattering by SL phonons and, in particular, by interface modes shows a pronounced resonant enhancement for incident photon energies matching the critical point energies of the SL.