Spectroscopy of neutral and charged exciton states in single CdSe/ZnS nanocrystals

Yann Louyer (1) , Louis Biadala (1) , Philippe Tamarat (1) , Brahim Lounis (1)

1 CPMOH - Centre de physique moléculaire optique et hertzienne

We report a low temperature spectroscopic study of the lowest-energy exciton states in single CdSe/ZnS colloidal nanocrystals (NCs). In their neutral charge state, the zero-phonon lines of the lowest two levels of the band-edge exciton fine structure are directly observed in the photoluminescence (PL) spectrum. The attribution of these lines is confirmed by polarization-resolved studies of the PL spectrum and decay. We also identified the emission from charged NCs which displays a single zero-phonon line ~17 meV redshifted with respect to the neutral NC emission lines. This bright trion state has a lifetime which ranges from 1.5 to 4.5 ns.

Domaines: Optique [physics.optics]; Physique Quantique [quant-ph]

Yann Louyer, Louis Biadala, Philippe Tamarat, Brahim Lounis. Spectroscopy of neutral and charged exciton states in single CdSe/ZnS nanocrystals. Applied Physics Letters, 2010, 96, pp.203111. ⟨10.1063/1.3435464⟩. ⟨hal-00611568⟩