MAPPING OF THE LOCAL CONFINEMENT POTENTIAL IN SEMICONDUCTOR NANOSTRUCTURES BY NEAR-FIELD OPTICAL SPECTROSCOPY

The optical properties of a new quantum-well-embedded GaAs quantum wir e structure grown on patterned (311)A GaAs surfaces are directly mappe d hy low temperature near-field scanning optical microscopy (NSOM). Ph otoluminescence excitation spectroscopy with subwavelength spatial res olution allows a quantitative analysis of tile local confinement poten tial of such structures which exhibit shallow barriers close to the qu antum wire. This local potential influences the carrier transport dyna mics within tile embedding quantum well and - in particular - carrier trapping from two-dimensional quantum well into one-dimensional wire s tates as is directly revealed in steady-state and time-resolved photol uminescence experiments at variable temperatures.