EXCITON TRANSFER DYNAMICS IN CDTE (CD,ZN)TE ASYMMETRIC DOUBLE-QUANTUM-WELL STRUCTURES/

Time-resolved photoluminescence measurements on CdTe/(Cd,Zn)Te asymmet ric double quantum wells (ADQWs) with electron and hole confinement po tentials of some tens of meV are reported. The carrier transfer from t he narrow into the wide well is evidenced by photoluminescence decay t imes of the narrow well as short as a few picoseconds. The observed tu nneling times depend strongly upon the barrier and well widths of the investigated samples which determine the relative position of spatial direct and cross exciton transitions. Very efficient tunneling is foun d in ADQWs in which the transfer of spatial direct excitons under emis sion of LO phonons is possible. In any case, one has to consider excit onic rather than single particle electron or hole states in order to e xplain the observed behaviour of the tunneling times.