Self-aggregation of quantum dots for very thin InAs layers grown-on GaAs

Low-temperature photoluminescence and transmission electron microscopy of InAs/GaAs quantum wells grown by molecular-beam epitaxy show that InAs self-aggregation of InAs quantum dots is a continuous phenomenon and that quantum dots nucleate at the well interfaces for nominal InAs layer thicknesses much smaller than commonly reported in the literature (i.e., 1.6+/-0.1 ML). A good agreement is also found between the self-aggregated dot sizes estimated from the photoluminescence emission energies and those directly obtained from transmission electron microscopy measurements.