Femtosecond near-field spectroscopy: carrier relaxation and transport in single quantum wires.
Quasi-two-colour femtosecond pump and probe spectroscopy and near-field scanning optical microscopy are combined to study the carrier dynamics in single semiconductor nanostructures. In temporally, spectrally and spatially resolved measurements with a time resolution of 200 fs and a spatial resolution of 200 nm, the non-linear change in reflectivity of a single quantum wire is mapped in real space and time. The experiments show that carrier relaxation into a single quantum wire occurs on a 100 fs time scale at room temperature. Evidence is given for a transient unipolar electron transport along the wire axis on a picosecond time and 100 nm length scale.
Emiliani
V
V
Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-2489 Berlin, Germany.
Guenther
T
T
Lienau
C
C
Nötzel
R
R
Ploog
K H
KH