Temperature dependence of the zero-phonon linewidth inInAs∕GaAsquantum dots

The temperature dependence of the width $\Gamma$ of the zero-phonon emission line in self-assembled $\mathrm{In}\mathrm{As}∕\mathrm{Ga}\mathrm{As}$ quantum dots has been studied for $T<50\mathrm{K}$. In single dot experiments on laterally patterned samples we find a linear increase of $\Gamma$ with $T$, with a slope that systematically increases with decreasing size of the mesa structure. This result is to be contrasted with the absence of such a dependence in four-wave mixing on unpatterned samples. The features are shown to be consistent with a theory in which the excitons interact with phonons whose linewidths are given by scattering at surfaces due to patterning.