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Structural characterization of ZnO thin films grown on various substrates by pulsed laser deposition

Novotný, M.; Čížek, J.; Kužel, R.; Bulíř, J.; Lančok, J.; Connolly, J.; McCarthy, E.; Krishnamurthy, Satheesh; Mosnier, J-P.; Anwand, W. and Brauer, G. (2012). Structural characterization of ZnO thin films grown on various substrates by pulsed laser deposition. Journal of Physics D: Applied Physics, 45, article no. 225101.

DOI (Digital Object Identifier) Link: https://doi.org/10.1088/0022-3727/45/22/225101
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Abstract

ZnO thin films were grown by pulsed laser deposition on three different substrates: sapphire (0 0 0 1), MgO (1 0 0) and fused silica (FS). The structure and morphology of the films were characterized by x-ray diffraction and scanning electron microscopy and defect studies were carried out using slow positron implantation spectroscopy (SPIS). Films deposited on all substrates studied in this work exhibit the wurtzite ZnO structure and are characterized by an average crystallite size of 20–100 nm. However, strong differences in the microstructure of films deposited on various substrates were found. The ZnO films deposited on MgO and sapphire single-crystalline substrates exhibit local epitaxy, i.e. a well-defined relation between film crystallites and the substrate. Domains with different orientation relationships with the substrate were found in both films. On the other hand, the film deposited on the FS substrate exhibits fibre texture with random lateral orientation of crystallites. Extremely high compressive in-plane stress of σ ~ 14 GPa was determined in the film deposited on the MgO substrate, while the film deposited on sapphire is virtually stress-free, and the film deposited on the FS substrate exhibits a tensile in-plane stress of σ ~ 0.9 GPa. SPIS investigations revealed that the concentration of open-volume defects in the ZnO films is substantially higher than that in a bulk ZnO single crystal. Moreover, the ZnO films deposited on MgO and sapphire single-crystalline substrates exhibit a significantly higher density of defects than the film deposited on the amorphous FS substrate.

Item Type: Journal Item
Copyright Holders: 2012 IOP Publishing Ltd
ISSN: 1361-6463
Project Funding Details:
Funded Project NameProject IDFunding Body
Not SetGAP108/11/0958Czech Science Foundation
Not SetGP202/09/P324Czech Science Foundation
Not SetGAP108/11/1539Czech Science Foundation
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Engineering and Innovation
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 37041
Depositing User: Satheesh Krishnamurthy
Date Deposited: 03 Apr 2013 09:35
Last Modified: 15 Mar 2017 15:40
URI: http://oro.open.ac.uk/id/eprint/37041
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