Degenerate Four Wave Mixing in Staggered Type-II AlxGa1−xAs/AlAs Multiple Quantum Well Structures
Recently much attention has been paid to carrier dynamics in staggered type-II multiple quantum well structures. In these systems, the energy level of the lowest Γ conduction electron state in a well layer is higher than that of the Γ-electron state in a barrier layer. Thus the photoexcited F-electrons in the well layer are easily scattered into the X-state in the barrier layer. The electrons scattered into the X-state in the barrier layer are expected to form X-Γ indirect excitons with holes in the well layer. We and several authors have measured these interlayer scattering times using femtosecond pump-and-probe technique with white light continuum [1,2,3]. However, the dephasing and momentum relaxation processes of the carriers in staggered type-II systems have not been understood. To clarify these relaxation processes, we have performed the time-resolved degenerate-four-wave mixing experiments in staggered type-II multiple quantum well structures.
KeywordsAnisotropy Recombination Coherence
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