Nanoscale Charge Motion in GaAs Nanobars Studied by Terahertz Spectroscopy

Abstract

Terahertz photoconductivity spectra and dynamics of electrons in GaAs nanobars were investigated using time-domain terahertz far-field and near-field spectroscopy. The photoconductivity spectra demonstrate that at low temperatures, band-bending leads to confinement of electrons to a volume smaller than the geometrical dimensions of the nanobars.

Furthermore, scanning near-field THz microscopy reveals a that band bending leads to a rapid escape of photogenerated charges away from the photoexcited surface.