Tunneling of spin polarized excitons in CdTe based asymmetric double quantum well structure

We have studied by means of cw magnetospectroscopy the tunneling of photoexcited carriers from a Cd1−xMnxTe spin-aligning QW to a CdTe QW through a Cd1−yMgyTe barrier. PLE results suggest that we deal with the tunneling of excitons as whole entities and that the effectiveness of the transfer is highest when exciton energy detuning equals two LO phonon energies. We observed that, during tunneling, photocarriers keep a substantial amount of their spin polarization, amounting to about 10%. The results prove that the injecting spin polarized excitons from spin-aligning QW to another QW via tunneling effect is feasible, and may lead to considerable spin populations.