  Time-resolved photoluminescence (PL) and micro-PL imaging were used to study
single CdS nanowires at 10 K. The low-temperature PL of all CdS nanowires
exhibit spectral features near energies associated with free and bound exciton
transitions, with the transition energies and emission intensities varying
along the length of the nanowire. In addition, several nanowires show spatially
localized PL at lower energies which are associated with morphological
irregularities in the nanowires. Time-resolved PL measurements indicate that
exciton recombination in all CdS nanowires is dominated by non-radiative
recombination at the surface of the nanowires.
