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Author Banin, U. ♦ Bruchez, M. ♦ Alivisatos, A. P. ♦ Ha, T. ♦ Weiss, S. ♦ Chemla, D. S.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ CADMIUM COMPOUNDS ♦ FLUORESCENCE ♦ CADMIUM SELENIDES ♦ CADMIUM SULFIDES ♦ TEMPERATURE DEPENDENCE ♦ AUGER EFFECT ♦ PHOTOIONIZATION ♦ EMISSION SPECTRA ♦ SEMICONDUCTOR MATERIALS ♦ SWITCHES
Abstract The on{endash}off intermittent behavior of emission from single CdSe/CdS core/shell nanocrystals was investigated as a function of temperature and excitation intensity. Off times were found to be independent of excitation power and the temperature dependence reveals substantial reduction in the number of on{endash}off cycles prior to final particle darkening at low temperatures. On times are found to vary linearly with excitation intensity over a broad range and the turn off rate shows activated Arrhenius behavior down to T=50thinspK. These observations are consistent with a darkening mechanism that is a combination of Auger photoionization and thermal trapping of charge. The inhomogeneity of various possible trap sites is discussed. A thermally activated neutralization process is required for the particle to return to the on state. The influence of shell composition on intermittency is compared for CdS and ZnS [M. Nirmal {ital et al.}, Nature {bold 383}, 802 (1996)]. {copyright} {ital 1999 American Institute of Physics.}
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 1999-01-01
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 110
Issue Number 2


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