Auger-process-induced charge separation in semiconductor nanocrystals

Victor I Klimov, Duncan W. McBranch

Research output: Contribution to journalArticle

110 Citations (Scopus)

Abstract

Femtosecond nonlinear transmission techniques are applied to study mechanisms for optical nonlinearities and ultrafast carrier dynamics in CdS nanocrystals (NC's). The obtained data indicate the change in a dominant hole relaxation channel at high pump levels where nonlinear recombination effects start to play a significant role. This is manifested as a distinct difference in nonlinear-optical responses measured at low and high pump intensities in quasiequilibrium at long times after excitation. The analysis of the wavelength and time dependence of the nonlinear transmission over a wide pump-intensity range shows clearly that this difference is due to an Auger-process-assisted trapping of holes at surface/interface-related states. This trapping leads to efficient charge separation and the generation of a dc electric field that modifies the nonlinear optical response in NC's at high pump intensities.

Original languageEnglish
Pages (from-to)13173-13179
Number of pages7
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume55
Issue number19
Publication statusPublished - May 15 1997

ASJC Scopus subject areas

  • Condensed Matter Physics

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