Sensitivity of exciton spin relaxation in quantum dots to confining potential

Mackowski, S.; Gurung, T.; Jackson, H. E.; Smith, L. M.; Heiss, W.; Kossut, J.; Karczewski, G.
March 2005
Applied Physics Letters;3/7/2005, Vol. 86 Issue 10, p103101
Academic Journal
We observe a strong dependence of the exciton spin relaxation in CdTe quantum dots on the average dot size and the depth of the confining potential. After rapid thermal annealing, which increases the average dot size and leads to weaker confinement, we measure the spin relaxation time of the quantum dot excitons to be 1.5 ns, as compared to 4.8 ns found previously for the as-grown CdTe quantum dots. The annealed CdTe quantum dots exhibit also smaller values of the absolute polarization of the quantum dot emission. This dramatic enhancement of the spin scattering efficiency upon annealing is attributed to increased mixing between different spin states in larger CdTe quantum dots.


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