MODIFICATION OF THE MICROROUGHNESS OF MOLECULAR-BEAM EPITAXIALLY GROWN GAAS/ALAS INTERFACES THROUGH CHANGES IN THE GROWTH TEMPERATURE

The interfacial properties of a series of GaAs/AlAs quantum wells (QWs) grown by molecular-beam epitaxy is examined using photoluminescence (PL). These high-quality QWs show splittings in the free exciton peaks, which indicate that large scale island structures exist at the interfaces. By changing the growth temperature we are able to shift the absolute energies of the excitons while keeping the same PL linewidths and lineshapes. Since the absolute energies of the excitons depend only on the GaAs and AlAs material parameters, we conclude that we are able to modify the small scale structure of the interfaces within the large scale islands by changing the growth temperature.