Optical transitions and acceptor binding energies in GaAs/AlxGa1−xAs single quantum well heterostructures grown by molecular beam epitaxy

Abstract

Single quantum wells of varying well size (150–300 Å) exhibiting sharp photoluminescence lines were grown by molecular beam epitaxy. Photoluminescence structure and intensity were comparable to high quality multiple quantum wells in that linewidths as low as 0.5 meV and transitions associated with free heavy-hole excitons as well as bound excitons and acceptor impurities were observed. Also reported for the first time in optical transmission measurements on single wells are excitonic absorption lines. These are as narrow as 0.38 meV full width at half-maximum. In contrast to earlier findings, the binding energy of the acceptor in single quantum wells displays the same functional dependence on the well thickness as in multiple quantum wells as a consequence of an improved bottom (inverted) interface.