EXCITON TRANSFER IN CDTE/(CD,MN)TE-DOUBLE QUANTUM-WELL STRUCTURES

A series of asymmetric CdTe (Cd,Mn)Te double quantum well structures, grown by MBE on InSb substrates, are studied by luminescence, excitation, and reflection spectroscopy in magnetic fields up to 9T. The well widths are 4 and 8 nm; respectively, the width of the inner barrier varies in the range 2.5 to 15 nm. The exciton transfer from the narrow into the wide well is found to be strongly dependent on the width of the inner barrier. The decay of the various luminescence bands after 5 ps-pulse excitation at various excitation energies and the dependence of the exciton transfer on a magnetic field are investigated. The results can be explained on the basis of an effective-lifetime model assuming an independent tunneling of electrons and holes. © 1992.