Two-dimensional exciton transport in GaAs/GaAlAs quantum wells

Abstract

Using microstructured masks and picosecond spectroscopy we have investigated the lateral expansion of two-dimensional excitons in GaAs/GaAlAs quantum wells with very high spatial resolution (∼0.1 μm). The exciton motion can be described by an isothermal diffusion which strongly depends on the well width. The increase of the excitonic diffusivity with increasing well width observed experimentally is attributed to the decrease of the interface roughness scattering probability.