Near-field optical spectroscopy of localized and delocalized excitons in asingle GaAs quantum wire - art. no. 075313

Excitons in a GaAs quantum wire are studied in high-resolution photolumines cence experiments performed at a temperature of about 10 K with a spatial r esolution of 150 nm, and a spectral resolution of 100 mu eV. We report an o bservation of quasi-one-dimensional excitons which are delocalized over a l ength of up to several microns along the quantum wire. Such excitons give r ise to a 10-meV broad luminescence band, representing a superposition of tr ansitions between different delocalized states. In addition, we find a set of sharp luminescence peaks from excitons localized on a sub-150-nm length scale. Theoretical calculations of exciton states in a disordered quasi-one -dimensional potential reproduce the experimental results.