Sensitivity of Exciton Spin Relaxation in Quantum Dots to Confining Potential
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. For the excitons confined to the as-grown CdTe quantum dots we find the spin relaxation time to be 4.8 ns. After rapid thermal annealing, which increases the average dot size and leads to weaker confinement, we measure the spin relaxation tine to be 1.5 ns, resulting in 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.