REAL-SPACE TRANSFER AND TRAPPING OF CARRIERS INTO SINGLE GAAS QUANTUMWIRES STUDIED BY NEAR-FIELD OPTICAL SPECTROSCOPY

We report the first near-field optical study of single GaAs quantum wi res grown on patterned (311)A GaAs surfaces. Spatially resolved optica l spectra at a temperature of 10 K give evidence for one-dimensional c arrier confinement and subband structure. At 300 K, electron-hole pair s in continuum slates undergo diffusive real-space transfer over a len gth of several microns determined by hole mobility and trapping by opt ical phonon emission. Optical phonon scattering of carriers in the qua ntum wire establishes a quasiequilibrium carrier distribution in both wire and continuum states.