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

We investigate the e5ect of magnetic 'elds, B, up to 42 T, on the photoluminescence spectra of In0:5Ga0:5As=GaAs single quantum wells (QWs). We 'ndthat the full-wid th at half-maximum, W , of the excitonic recombination spectrum increases signi'cantly at these high 'elds to an extent depending on the direction of B. The increase of W with magnetic 'eldis d ue to the squeezing of the exciton wave function, which increases the e5ect of the QW potential energy ;uctuations 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 'eld dependence of the spatial extent of the exciton in the QW. ? 2002 Elsevier Science B.V. All rights reserved.