Low-temperature (<40 K) photoluminescence (PL) spectra of individual CdSe nanocrystal quantum wires exhibit narrow (<5 meV) isolated peaks spanning a range ≤50 meV. We attribute these features to emission of excitons localized in shallow (a few meV deep) tight potential minima superimposed on longer-scale and larger-amplitude variations of the potential energy. Spectrally resolved PL dynamics reveal decreasing exciton-decay rates with decreasing emission energy. These observations are consistent with exciton relaxation within a manifold of localization sites characterized by an exponential density of states.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Aug 11 2009|