EXCITON TRANSPORT INTO A SINGLE GAAS QUANTUM-WIRE STUDIED BY PICOSECOND NEAR-FIELD OPTICAL SPECTROSCOPY

We report a time-resolved near-field luminescence study of excitonic r eal-space transfer into single GaAs quantum wires. Excitons generated by local optical excitation in a 250 nm spot undergo diffusive transpo rt over a length of several microns and are subsequently trapped into the quantum wire by optical phonon emission. Local energy barriers in the vicinity of the quantum wire, originating from the epitaxial growt h mechanism of the nanostructure, directly influence the real-space tr ansfer dynamics and trapping efficiency. (C) 1998 American Institute o f Physics. [S0003-6951(98)04941-9].