Charged excitons in modulation-doped quantum wires

We report on the observation of negatively- and positively-charged excitons in the photoluminescence spectra of V-groove quantum wires. The. charged exciton binding energy increases with the strength of the quantum confinement. We demonstrate that fluctuations of the confinement potential cause the localization of the exciton and of the charged exitons on the same location. We discover that a large fraction of the enhancement of the charged exciton "binding energies" has a kinetic origin associated with the recoil energy transferred to the remaining carrier during the emission process.