EXCITON SPIN RELAXATION IN SEMICONDUCTOR QUANTUM-WELLS - THE ROLE OF DISORDER

Ultrafast pulse measurements on high-quality (Zn,Cd)Se/ZnSe quantum we lls yield the very surprising result that the decay of the exciton spi n transients after resonant excitation with circularly polarized light is even faster than the exciton dephasing time. We demonstrate that t his fact is a direct consequence of (alloy) disorder which gives rise to a kind of inhomogeneous broadening and associated interference effe cts for spin dynamics across the band of localized exciton states. [S0 031-9007(98)07100-2].