Nanoscale mapping of confinement potentials in single semiconductor quantum wires by near-field optical spectroscopy

The quasi-one-dimensional confinement potential and its influence on carrier transport in a GaAs quantum wire structure are directly mapped by low-temperature near-field scanning optical spectroscopy with subwavelength spatial resolution. Shallow asymmetric potential barriers in the vicinity of the quantum wire are detected, and their height and width are determined quantitatively: We demonstrate the strong influence of such local barriers on carrier transport and trapping into the quantum wire, suppressing carrier trapping at low temperature.