Abstract
The in-plane motion of negatively charged excitons in modulation-doped GaAs quantum wells (QW’s) was studied by means of spatially resolved photoluminescence spectroscopy. In the highest-quality QW’s, resonantly excited were observed diffusing from the excitation region, characterized by a mobility as high as independent of temperature and electron density. Under the application of an electric field in the plane of the QW, were found to drift in the direction opposite to the field, whereas neutral excitons (X) do not drift under similar conditions. The results demonstrate that can exist as a free quasiparticle in the best-quality samples. The simultaneous motion of nonresonantly excited X and was studied as a function of the electron density in the QW. The data reveal that the spatial distribution of X and is mainly determined by the motion of X that locally form
- Received 29 January 2003
DOI:https://doi.org/10.1103/PhysRevB.68.205304
©2003 American Physical Society