Manipulating luminescence in semiconductor nanostructures via field-effect-tuneable potentials

摘要

The luminescence properties of III-V quantum wells under the influence of field-effect-tuneable and laterally modulated potentials are reviewed. Large electric fields generated in the quantum well plane cause a modulation of the quantum well absorption via the Franz-Keldysh effect as well as a reversible separation of optically excited electron-hole pairs. The electron-hole pair separation by field effect can prolong the recombination lifetimes by many orders of magnitude and yields a controllably delayed reemission of luminescence radiation. Dynamic in-plane electric fields caused by the propagation of surface acoustic waves on piezoelectric heterostructures make possible spatially and temporarily delayed luminescence whereas a two-dimensional modulation of the electrostatic potential enables the delayed storage of optical images. Spatial modulation of the quantum confined Stark effect via the out-of-plane electric field is employed to realize tuneable excitonic traps and to study macroscopic transport of long-living, spatially indirect excitons in suitably designed double quantum wells. This is possibly paving the way for the observation of excitonic Bose-Einstein condensation in quantum well structures.. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.