Abstract
We report polarization-resolved, low-temperature, high-spectral-resolution studies of the photoluminescence from individual CdSe nanocrystal quantum dots (NQDs). The spectra reveal a ‘fine structure’ splitting of the bright exciton state in a subset of the studied NQDs. The two fine structure states are spectrally separated by an energy of up to depending on NQD size and are characterized by linearly (and orthogonally) polarized emission dipoles. The average splitting scales approximately with inverse NQD volume, consistent with an anisotropic electron-hole exchange interaction which can result from a breakdown of cylindrical symmetry in some of the NQDs.
- Received 2 August 2007
DOI:https://doi.org/10.1103/PhysRevB.77.035328
©2008 American Physical Society