The control over the spectral broadening of an ensemble of emitters, mainly attributable to
the size and shape dispersion and the homogenous broadening mechanisms, is crucial to
several applications of quantum dots. We present a convenient self-assembly approach to
deliver strain-free GaAs quantum dots with size dispersion below 10%, due to the control of
the growth parameters during the preliminary formation of the Ga droplets. This results in an
ensemble photoluminescence linewidth of 19 meV at 14 K. The narrow emission band and …