Abstract
We perform for the first time photoluminescence excitation (PLE) studies of individual nanocrystals (NCs) that reveal the structure of excited-state transitions not obscured by ensemble averaging. Single-NC PLE spectra strongly deviate from a traditional idealized picture of sharp, quasiatomic resonances. We detect only a few relatively narrow transitions (3–4 meV) at the band edge, while at higher spectral energies, we observe a broad structureless feature separated from the band-edge peaks by a “minigap.” These observations can be rationalized by analyzing hole intraband relaxation behavior.
- Received 22 April 2004
DOI:https://doi.org/10.1103/PhysRevLett.93.187402
©2004 American Physical Society