Reconciling results of MOCVD of a CNT composite with equilibrium thermodynamics

Dhar, Sukanya and Arod, Pallavi and Shivashankar, SA (2016) Reconciling results of MOCVD of a CNT composite with equilibrium thermodynamics. In: JOURNAL OF CRYSTAL GROWTH, 442 . pp. 41-46.

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Abstract

Composition and microstructure of the composite films can be tailored by controlling the CVD process parameters if an appropriate model can be suggested for quantitative prediction of growth. This is possible by applying equilibrium thermodynamics. A modification of such standard modeling procedure was required to account for the deposition of a hybrid film comprised of carbon nanotubes (CNTs), metallic iron (Fe), and magnetite (Fe3O4), a composite useful for energy storage. In contrast with such composite nature of the deposits obtained by inert-ambient CVD using Fe(acac)3 as precursor, equilibrium thermodynamic modeling with standard procedure predicts the deposition of only Fe3C and carbon, without any co-deposition of Fe and Fe3O4. A modification of the procedure comprising chemical reasoning is therefore proposed herein, which predicts simultaneous deposition of FeO1-x, Fe3C, Fe3O4 and C. At high temperatures and in a carbon-rich atmosphere, these convert to Fe3O4, Fe and C, in agreement with experimental CVD. Close quantitative agreement between the modified thermodynamic modeling and experiment validates the reliability of the modified procedure. Understanding of the chemical process through thermodynamic modeling provides potential for control of CVD process parameters to achieve desired hybrid growth. (C) 2016 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	JOURNAL OF CRYSTAL GROWTH
Publisher:	ELSEVIER SCIENCE BV
Additional Information:	Copy right for this article belongs to the ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Keywords:	Growth models; Nano structures; Metalorganic chemical vapor deposition; Nanomaterials; Oxides
Department/Centre:	Division of Chemical Sciences > Materials Research Centre Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	11 May 2016 05:15
Last Modified:	11 May 2016 05:15
URI:	http://eprints.iisc.ac.in/id/eprint/53761

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