Abstract
We report on polarization-resolved resonant photoluminescence (PL) spectroscopy of bright (spin 1) and dark (spin 2) excitons in colloidal nanocrystal quantum dots. Using high magnetic fields to , we resonantly excite (and selectively analyze PL from) spin-up or spin-down excitons. At low temperatures and above , the spectra develop a narrow, circularly polarized peak due to spin-flipped bright excitons. Its evolution with magnetic field directly reveals a large , intrinsic fine-structure splitting of bright excitons, due to anisotropic exchange. These findings are supported by time-resolved PL studies and polarization-resolved PL from single nanocrystals.
- Received 13 March 2006
DOI:https://doi.org/10.1103/PhysRevB.73.241313
©2006 American Physical Society