Chemically synthesized InP/ZnS core/shell quantum dots (QDs) are studied using time-resolved photoluminescence spectroscopy and x-ray diffraction. Zinc stearate, which is added during the synthesis of the InP core, significantly improves the optical characteristics of the QDs. The luminescence quantum yield (QY) reaches 60%–70% and the emission is tunable from 485 to 586 nm by varying the molar ratio and growth temperature. The observed increased Stokes shift, luminescence decay time, and QY in the presence of Zn are rationalized by the formation of an In(Zn)P alloy structure that causes band-edge fluctuation to enhance the confinement of the excited carriers.
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See supplementary material at http://dx.doi.org/10.1063/1.3515417 for synthesis of In(Zn)P alloy core/ZnS shell QDs, measurement techniques, and powder X-ray diffraction data.
© 2010 American Institute of Physics.
2010
American Institute of Physics
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