InAs/AlGaAs QDs for intersubband devices

InAs quantum dots were grown on AlxGa1−xAs surfaces with varying Al concentrations. Atomic force microscopy measurements conducted on surface quantum dots showed that surfaces with higher Al concentrations produce smaller dots compared to GaAs surfaces. Photoluminescence measurements performed on buried quantum dots showed a blue shift and spectral broadening of the luminescence signal for increasing Al concentrations. For Al concentrations of 45% quantum dots with ground state energies above the GaAs bandgap could be achieved. High resolution transmission electron microscopy measurements clearly showed the presence of the dots and were in good agreement with the AFM measurements.