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Journal of Nanomaterials
Volume 2007, Article ID 84845, 17 pages
http://dx.doi.org/10.1155/2007/84845
Review Article

Well-Aligned IrO2 Nanocrystals

1Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan
2Biomedical NMR Laboratory, Howard University, Washington, DC 20059, USA
3Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
4Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan
5Department of Electrical Engineering, National Taiwan Ocean University, Keelung 202, Taiwan

Received 27 February 2007; Accepted 16 August 2007

Academic Editor: Berger Shlomo

Copyright © 2007 Alexandru Korotcov et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We review the results of synthesis of well-aligned IrO2 nanocrystals (NCs) on sapphire (SA), LiNbO3 (LNO), LiTaO3 (LTO) substrates via reactive magnetron sputtering and metal-organic chemical vapor deposition. The surface morphology and structural properties of the as-deposited NCs were characterized. Field emission scanning electron microscopy micrographs reveal that NCs grown on SA(100)/LNO(100) are vertically aligned, while the NCs on SA(012)/LTO(012) and SA(110) contain singly and doubly tilted alignments, respectively, with a tilt angle of 35 from the normal to the substrates. NCs grown on SA(001) show in-plane alignment with mosaic structure. The X-ray diffraction results indicate that the NCs are (001), (101), and (100) oriented on SA(100)/LNO(100), SA(012)/LTO(012)/SA(110), and SA(001) substrates, respectively. A strong substrate effect on the alignment of the IrO2 NCs deposition has been demonstrated. The roles of different substrates in the formation of various textures of nanocrystalline IrO2 are studied and the possible mechanisms have been discussed.