Ultrafast dynamics of inter- and intraband transitions in semiconductor nanocrystals: Implications for quantum-dot lasers

Victor I Klimov, Ch J. Schwarz, D. W. McBranch, C. A. Leatherdale, M. G. Bawendi

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Application of femtosecond transient absorption in the visible and near-IR spectral ranges and time-resolved photoluminescence allows us to separate electron and hole relaxation paths and to map the structure of interband and intraband optical transitions in CdSe and CdS nanocrystals (NC's) with a wide range of surface properties. In contrast to electron relaxation, which is controlled by NC surface passivation, depopulation of hole quantized states is extremely fast (sub-ps-to-ps time scales) in all types samples, independent of NC surface treatment (including NC's overcoated with a ZnS layer). Our results suggest that ultrafast hole dynamics are not due to trapping at localized surface defects such as a vacancy, but rather arise from relaxation into intrinsic NC states or intrinsically unpassivated interface states.

Original languageEnglish
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number4
Publication statusPublished - Jul 15 1999


ASJC Scopus subject areas

  • Condensed Matter Physics

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