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Surface Stoichiometry of CdSe Nanocrystals

Published online by Cambridge University Press:  09 August 2011

Jason Taylor ,
Tadd Kippeny ,
Jonathan C. Bennett ,
Mengbing Huang ,
Leonard C. Feldman  and
Sandra J. Rosenthal
Jason Taylor
Affiliation:
Department of Chemistry
Tadd Kippeny
Affiliation:
Department of Chemistry
Jonathan C. Bennett
Affiliation:
Department of Physics, Vanderbilt University, Nashville, TN 37235
Mengbing Huang
Affiliation:
Department of Physics, Vanderbilt University, Nashville, TN 37235
Leonard C. Feldman
Affiliation:
Department of Physics, Vanderbilt University, Nashville, TN 37235
Sandra J. Rosenthal
Affiliation:
Department of Chemistry
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Abstract

Rutherford backscattering spectroscopy (RBS) has been applied to determine the constitution of prototypical CdSe nanocrystals synthesized by the high temperature pyrolysis of organometallics in trioctylphosphine oxide (TOPO). The diameter of the nanocrystals was varied from 22 Å to 58 Å. For all nanocrystal sizes the nanocrystals are Cd rich with an average Cd:Se ratio of 1.2 ± 0.1. The Cd:Se stoichiometery is independent of the starting Cd:Se ratio used for nanocrystal preparation, indicating the excess Cd is not associated with the initial abundance but is an intrinsic property of nanocrystals prepared by this method. The size dependence of excess Cd indicates the extra Cd is on the surface of the crystallite. The coverage of the surface passivating TOPO ligands has also been determined and is larger than reported in previous X-ray photoelectron spectroscopy (XPS) studies of Bowen Katari et al. The origin and structural implications of non-stoichoimetric Cd are discussed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 536: Symposium F – Microcrystalline & Nanocrystalline Semiconductors - 1998 , 1998 , 413
Copyright
Copyright © Materials Research Society 1999

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References

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