EXCITON MIXING IN THE MAGNETOPHOTOLUMINESCENCE EXCITATION-SPECTRA OF SHALLOW STRAINED INXGA1-XAS GAAS QUANTUM-WELLS/

We report highly resolved photoluminescence excitation spectra of exci tons in intrinsic pseudomorphic InxGa1-xAs/GaAs quantum wells (QW's). The QW parameters are chosen such that only the n(z)=1 electron and ho le subbands are confined and the light-hole-heavy-hole exciton splitti ng exceeds the exciton binding energy. By using circularly polarized l ight the fine structure of excitonic transitions is well resolved in t he spectra of quantum wells at magnetic fields H less than or equal to 8 T. We observe a strong mixing of light- and heavy-hole excitons whi ch causes optical transitions into high-angular-momentum exciton state s and results in strong anticrossing effects. Two excited states of th e exciton located at approximate to 1 and 2.5 meV above the is light-h ole exciton state have been observed and are related to exciton states with the carrier-wave-function delocalized into the GaAs barriers.