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

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. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)