Real-Space Transfer and Trapping of Carriers into Single GaAs Quantum Wires Studied by Near-Field Optical Spectroscopy

We report the first near-field optical study of single GaAs quantum wires grown on patterned $\left(311\right)A$ GaAs surfaces. Spatially resolved optical spectra at a temperature of 10 K give evidence for one-dimensional carrier confinement and subband structure. At 300 K, electron-hole pairs in continuum states undergo diffusive real-space transfer over a length of several microns determined by hole mobility and trapping by optical phonon emission. Optical phonon scattering of carriers in the quantum wire establishes a quasiequilibrium carrier distribution in both wire and continuum states.