Dynamical Optical Nonlinearities Induced by Interlayer Carrier Transfer in Type-II Al_xGa_1−xAs/AlAs Multiple-Quantum-Well Structures

Abstract

We have observed microsecond decay of bleaching and anomalous induced absorption in staggered alignment type-II Al_xGa_1−xAs/AlAs ternary alloy multiple-quantum-well structures. In a microsecond time scale, the time evolution of bleaching was almost the same as that of type-II photoluminescence. The induced absorption, which occurs immediately after the photoexcitation, was observed at the low-energy tail of the exciton. These results indicate an interlayer Γ-X scattering process and suggest the resultant spatial redistribution of carriers.