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Proceedings Paper

Synthesis and characterization of colloidal CdTe nanocrystals
Author(s): Fred Semendy; Gomatam Jaganathan; Nibir Dhar; Sudhir Trivedi; Ishwara Bhat; Yuanping Chen
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Paper Abstract

We synthesized CdTe nano crystals (NCs) in uniform sizes and in good quality as characterized by photoluminescence (PL), AFM, and X-ray diffraction. In this growth procedure, CdTe nano-crystal band gap is strongly dependent on the growth time and not on the injection temperature or organic ligand concentration. This is very attractive because of nano-crystal size can be easily controlled by the growth time only and is very attractive for large scale synthesis. The color of the solution changes from greenish yellow to light orange then to deep orange and finally grayish black to black over a period of one hour. This is a clear indication of the gradual growth of different size (and different band gap) of CdTe nano-crystals as a function of the growth time. In other words, the size of the nano-crystal and its band gap can be controlled by adjusting the growth time after injection of the tellurium. The prepared CdTe NCs were characterized by absorption spectra, photoluminescence (PL), AFM and X-ray diffraction. Measured absorption maxima are at 521, 560, 600 and 603 nm corresponding to band gaps of 2.38, 2.21,2,07 and 2.04 eV respectively for growth times of 15, 30, 45 and 60 minutes. From the absorption data nano-crystal growth size saturates out after 45 minutes. AFM scanning of these materials indicate that the size of these particles is between 4 - 10 nm in diameter for growth time of 45 minutes. XD-ray diffraction indicates that these nano crystals are of cubic zinc blende phase. This paper will present growth and characterization data on CdTe nano crystals for various growth times.

Paper Details

Date Published: 9 September 2008
PDF: 8 pages
Proc. SPIE 7039, Nanoengineering: Fabrication, Properties, Optics, and Devices V, 70391L (9 September 2008); doi: 10.1117/12.803826
Show Author Affiliations
Fred Semendy, Army Research Labs. (United States)
Gomatam Jaganathan, Brimrose Corp. (United States)
Nibir Dhar, Army Research Labs. (United States)
Sudhir Trivedi, Brimrose Corp. (United States)
Ishwara Bhat, Rensselaer Polytechnic Institute (United States)
Yuanping Chen, Army Research Labs. (United States)

Published in SPIE Proceedings Vol. 7039:
Nanoengineering: Fabrication, Properties, Optics, and Devices V
Elizabeth A. Dobisz; Louay A. Eldada, Editor(s)

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