Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-03T00:39:21.747Z Has data issue: false hasContentIssue false

Time Evolution of the Microstructure of VO2(B) Films Deposited on Glass by MOCVD

Published online by Cambridge University Press:  11 February 2011

M. B. Sahana
Affiliation:
Materials Research Centre, Indian Institute of Science, Bangalore -560 012, India
G. N. Subbanna
Affiliation:
Materials Research Centre, Indian Institute of Science, Bangalore -560 012, India
S. A. Shivashankar
Affiliation:
Materials Research Centre, Indian Institute of Science, Bangalore -560 012, India
Get access

Abstract

Thin films of VO2(B), a metastable polymorph of vanadium dioxide, have been grown on glass by low-pressure metalorganic chemical vapor deposition (MOCVD). The films grown for 90 minutes have atypical microstructure, comprising micrometer-sized, island-like entities made up of numerous small, single-crystalline platelets (≅1 μm) emerging orthogonally from larger ones at the center. Microstructure evolution as a function of deposition time has been examined by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The metastable VO2(B) transforms to the stable rutile (R) phase at 550°C in inert ambient, which on cooling convert reversibly to M phase. Electron microscopy shows that annealing leads to the disintegration of the VO2(B) platelets into small crystallites of the rutile phase VO2(R), although the platelet morphology is retained. The magnitude of the jump in resistance at the semiconductor-to-metal, VO2(M)→VO2(R) phase transition depends on the arrangement of polycrystalline platelets in the films.

Type
Research Article
Copyright
Copyright © Materials Research Society 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Zylbersztejn, A. and Mott, N.F., Phys. Rev. B 11, 4383 (1975).Google Scholar
2. Deki, S., Aoi, Y., and Kajinami, A., J. Mate. Sci., 32, 4269 (1997).Google Scholar
3. Sahana, M. B., Dharmaprakash, M. S., and Shivashankar, S. A., J. Mat. Chem. 12, 333 (2002).Google Scholar
4. Sahana, M.B, Subbanna, G.N and Shivashankar, S.A., J. Appl. Phys. 92, 6495 (2002).Google Scholar
5. Leroux, Ch., Nihoul, G., and van Tendeloo, G., Phys. Rev. B57, 5111 (1998).Google Scholar
6. Bauer, E., Trans.9th Vac. Sym. AVS, 1962, edited by Bancroft, G.H. (Macmillan, New York, p.35.Google Scholar
7. De Natale, J.F., Hood, P.J., and Harker, A.B., J. Appl. Phys., 66, 5844 (1989).Google Scholar