X-ray characterization of LiNbO3 films grown by pulsed laser deposition onSrTiO3(100), NdGaO3(110) and MgO(111) substrates

We investigate the epitaxial properties of LiNbO3 films grown by pulsed las er deposition on different single-crystal substrates such as SrTiO3 (100), NdGaO3(110) and MgO(111) by using several X-ray diffraction methods: conven tional X-ray diffraction,, X-ray reciprocal space mapping and azimuthal X-r ay scans. The different domain structures and mosaic spreads observed for f ilms deposited on different substrates are explained by different crystallo graphic symmetry of substrate surfaces and by different lattice mismatch va lues. In particular, the LiNbO3 films grown on NdGaO3 (110) exhibit two twi nned crystalline domains which are tilted in a well-defined fashion in orde r to minimize the strain energy and to accommodate the lattice mismatch bet ween the film and the substrate. The films grown on SrTiO3 (100) show four domains and a larger mosaic spread, while the films grown on MgO(111) are s ingle oriented due to the good lattice accommodation. (C) 2000 Elsevier Sci ence B.V. All rights reserved.