Comparative investigation of the interface quality of GaAs/AlGaAs quantum wells grown by MBE.

We have performed a comparative study of low temperature photoluminescence (PL), photoluminescence excitation spectroscopy (PLE), transmission electron microscopy (TEM) and secondary ion mass spectroscopy (SIMS) on GaAs/AlGaAs quantum wells (QW) grown by molecular beam epitaxy (MBE). The QW widths derived from reflection high energy electron diffraction (RHEED) intensity oscillations are compared with TEM results and SIMS measurements. In order to study the effect of growht interruption on optical properties we have grown QWs without and with growth interruption. For QWs grown without growth interruption we obtained an interface of one monolayer. QWs growth interruption exhibit a series of emission lines in PL which are attributed, based on the comparison of PL and PLE data, to free and bound exciton recombination. The above assignment is confirmed by excitation power density dependent PL. For QWs grown with growth interruption we obtained atomically flat interfaces.