Band Structure Effects on Stark Levels and Real Space Electron Transfer in Perfect and Imperfect Quantum Wells and Superlattices
We have studied the effects of level crossing and valley mixing on Stark shifts, electron lifetimes, and cross interface electron transfer in perfect and, for the first time, also in imperfect GaAs-AlAs heterostructures. We identify the limits of applicability of the particle in a box picture for modelling Stark resonances. We find that the valley mixing is strong in the vicinity of X-resonances and determine their effective widths. In particular, in type II structures with medium thick (e.g. 100Å) barriers transfer into X-levels is fast compared to the relevant tunnelling time. The phonon-assisted Γ-X transfer is reduced compared to that in bulk GaAs. The breakdown of the translational symmetry in the interface plane has a small effect on valley mixing in the growth direction but strongly affects the states in the interface plane.
KeywordsInterface Plane Stark Shift Bulk GaAs Super Lattice Optical Matrix Element
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