Linewidth broadening of excitonic luminescence from quantum wells in pulsed magnetic fields

We investigate the effect of magnetic fields, B, up to View the MathML source, on the photoluminescence spectra of In0.5Ga0.5As/GaAs single quantum wells (QWs). We find that the full-width at half-maximum, W, of the excitonic recombination spectrum increases significantly at these high fields to an extent depending on the direction of B. The increase of W with magnetic field is due to the squeezing of the exciton wave function, which increases the effect of the QW potential energy fluctuations on the line width. A statistical model for the QW interface disorder is used to explain these results. In turn, this allows us to probe the magnetic field dependence of the spatial extent of the exciton in the QW.