Spectroscopy and carrier dynamics in CdSe self-assembled quantum dots embedded in ZnxCdyMg1-x-ySe

Comanescu, G.; Wang, W. B.; Gundry, S.; Das, B.; Alfano, R. R.; Perez-Paz, M. N.; Tamargo, M. C.; Muñoz, M.; Popov, I.; Isaacs, L. L.
June 2005
Applied Physics Letters;6/20/2005, Vol. 86 Issue 25, p253113
Academic Journal
Time-resolved and steady-state photoluminescence, reflectivity, and absorption experiments were performed on CdSe quantum dots in ZnxCdyMg1-x-ySe barriers. Studies of the capture times of the photoexcited carriers into the quantum dots and of electron-hole recombination times inside the dots were performed. Photoluminescence rise time yielded capture times from 20 ps to 30 ps. All samples exhibit fast and slow photoluminescence decays, consistent with observing two independent but energetically overlapping decays. The faster relaxation times for the sample emitting in the blue range is 90 ps, whereas for the two samples emitting in the green it is 345 ps and 480 ps. The slower relaxation times for the sample emitting in blue is 310 ps, whereas for the samples emitting in green is 7.5 ns. These results are explained on the basis of the structural differences among the quantum-dot samples.


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