Narrow (≈4 meV) inhomogeneous broadening and its correlation with confinement potential of pyramidal quantum dot arrays

The inhomogeneous broadening in the luminescence spectra of ordered arrays of pyramidal GaAs/AlGaAs semiconductor quantum dots (QDs) was studied as a function of the dot size. Dot arrays with inhomogeneous broadening as small as 4.1 meV and a corresponding ground state to first excited state transition separation of 28 meV were obtained. By evaluating the QD energy levels using a multiband k∙p model, the authors estimated that the observed inhomogeneous broadening corresponds to dot height fluctuations of about 1–2 ML across the array.