Temperature dependence of the exciton decay times of different quantum structures coexisting in a ZnSe/CdSe/ZnSe heterostructure

Study by time-resolved photoluminescence shows that two classes of quantum structures coexist in a ZnSe/CdSe/ZnSe heterostructure in which the CdSe co verage is less than the critical thickness. Excitons from class-A structure s dominate the emission spectrum and exhibit temperature-independent decay times, demonstrating quantum-dot-like properties. On the other hand, excito nic transitions from class-B structures are characterized by decay times th at depend linearly on temperature, indicating two-dimensional features. The re is a sharp transition from class-A to class-B excitons as the emission e nergy goes from higher to lower energies across the emission band. (C) 2000 American Institute of Physics. [S0021-8979(00)03221-7].