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Metalorganic chemical vapor deposition of highly oriented thin film composites of V2O5 and V6O13: Suppression of the metal–semiconductor transition in V6O13

Sahana, MB and Shivashankar, SA (2004) Metalorganic chemical vapor deposition of highly oriented thin film composites of V2O5 and V6O13: Suppression of the metal–semiconductor transition in V6O13. In: Journal of Materials Research, 19 (10). pp. 2859-2870.

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Abstract

Thin films of vanadium oxides were grown on fused quartz by metalorganic chemical vapor deposition using vanadyl acetylacetonate as the precursor. Growth at temperatures \geq560 °C results in composites of strongly (00l)-oriented $V_{2}O_{5}$ and $V_{6}O_{13}$. The dominant phase of the film changes from $V_{2}O_{5}$ to $V_{6}O_{13}$, and back to $V_{2}O_{5}$, as the growth temperature is raised from 560 to 570 °C, then to 580 °C, as evidenced by x-ray diffraction and Rutherford backscattering analyses. This reentrant-type growth trend was interpreted on the basis of the small difference in the free energy of formation of $V_{2}O_{5}$ and $V_{6}O_{13}$ and the presence of metal–oxygen bonds in the precursor. In contrast with single-crystalline $V_{6}O_{13}$, the film predominantly composed of highly oriented single-crystalline platelets of $V_{6}O_{13}$ did not undergo the semiconductor–metal transition at -123° K, despite the connectivity being well above the percolation threshold. Instead, a semiconductor-to-semiconductor transition was observed in this film, which is explained in terms of the observed relaxation of the edges of all the platelets of metallic $V_{6}O_{13}$ to semiconducting $V_{2}O_{5}$.

Item Type: Journal Article
Additional Information: The copyright belongs to Materials Research Society.
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Date Deposited: 11 Nov 2004
Last Modified: 19 Aug 2011 10:54
URI: http://eprints.iisc.ernet.in/id/eprint/2312

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