Effect of lattice mismatch on the epitaxy of sol-gel LiNbO3 thin films

Autor: Fred F. Lange, T. A. Derouin, Xuehua Wu, Charles D. E. Lakeman, James S. Speck
Rok vydání: 1997
Předmět:
Zdroj: Journal of Materials Research. 12:1391-1400
ISSN: 2044-5326
0884-2914
DOI: 10.1557/jmr.1997.0189
Popis: A solution precursor method based on metal alkoxides was used to produce epitaxial LiNbO3 thin films, ≈200 nm thick, on (0001) sapphire substrates. Transmission electron. microscopy revealed that the major cause of surface roughness in these films was grain boundary grooves between mosaic grains with misorientations ≤5°. It is postulated that these low angle boundaries directly result in surface grooving and roughness. The epitaxial films also contained two distinguishable variants in the film/substrate interfacial plane, namely, an aligned variant, and a 60° rotated variant, . A seeded grain growth method was used to minimize the presence of the 60° rotated variant. An epitaxial buffer layer of Fe2O3 was used to lower the mismatch strain, eliminate the 60° rotated variant, and reduce the mosaic nature of the LiNbO3 film. X-ray rocking curve full-width-at-half-maximum (FWHM) values measured on the film peak indicate that the mosaic character can be reduced from 1.5° to 0.76° by using a buffer layer.
Databáze: OpenAIRE
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