Universität zu Köln

Graf, David ORCID: 0000-0002-0504-8527, Schlaefer, Johannes, Garbe, Simon, Klein, Axel ORCID: 0000-0003-0093-9619 and Mathur, Sanjay (2017). Interdependence of Structure, Morphology, and Phase Transitions in CVD Grown VO2 and V2O3 Nanostructures. Chem. Mat., 29 (14). S. 5877 - 5886. WASHINGTON: AMER CHEMICAL SOC. ISSN 1520-5002

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Abstract

Phase selective chemical vapor deposition of nanostructured vanadium dioxide (VO2) and sesquioxide (V2O3) was achieved by deploying [V(OR)(4)](n) (R = Bu-t, n = 1 (1), R = Et, n = 3 (2), R = Me, n = 4 (3)). Use of [V((OBu)-Bu-t)(4)] (1) produced thin films of monoclinic VO2 (Ml) at 700 and 800 degrees C consisting of anisotropic nanostructures with high crystallinity and small hysteresis in the metal-to-semiconductor transition (MST). Film morphologies manifested strong dependence on growth temperatures and exhibited pronounced texturing effects at high temperatures (>700 degrees C). The microstructure of the films was found to significantly affect the MST behavior of VO2 films. DTA measurements of VO2 films showed MST at 63 degrees C (700 degrees C) and 65 degrees C (800 degrees C), much lower than the transition temperature observed in single crystal material (68 degrees C). Precursors were characterized in the solid state (XRD) and solution state (temperature dependent EPR, NMR) to reveal an association dissociation equilibrium in solution (complexes 2 and 3), involving monomeric, dimeric, and oligomeric species. Use of 2 and 3 as single precursors produced thin films of crystalline V2O3 consisting of nanosheets (5 nm) with a flower-like morphology.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Graf, David UNSPECIFIED orcid.org/0000-0002-0504-8527 UNSPECIFIED Schlaefer, Johannes UNSPECIFIED UNSPECIFIED UNSPECIFIED Garbe, Simon UNSPECIFIED UNSPECIFIED UNSPECIFIED Klein, Axel UNSPECIFIED orcid.org/0000-0003-0093-9619 UNSPECIFIED Mathur, Sanjay UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-224741
DOI:	10.1021/acs.chemmater.7b01018
Journal or Publication Title:	Chem. Mat.
Volume:	29
Number:	14
Page Range:	S. 5877 - 5886
Date:	2017
Publisher:	AMER CHEMICAL SOC
Place of Publication:	WASHINGTON
ISSN:	1520-5002
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Inorganic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CHEMICAL-VAPOR-DEPOSITION; DIOXIDE THIN-FILMS; ATOMIC LAYER DEPOSITION; DOPED VANADIUM DIOXIDE; OXIDE; COATINGS; PRECURSOR; STRAIN Multiple languages Chemistry, Physical; Materials Science, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/22474