Journal of Crystal Growth 277 (2005) 26–31 Growth and characterization of a-axis textured ZnO thin films L.C. Nistor a,Ã , C. Ghica a , D. Matei b , G. Dinescu b , M. Dinescu b , G. Van Tendeloo c a Microstructure of Defects in Solids, National Institute for Materials Physics, Atomistilor 105 bis, P.O. Box MG-7, RO-77125 Magurele, Ilfov, Romania b National Institute of Lasers, Plasma and Radiation Physics, P.O. Box MG-27, RO-77125 Magurele, Ilfov, Romania c EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium Received 16 July 2004; accepted 30 December 2004 Communicated by D.T.J. Hurle Available online 1 February 2005 Abstract Smooth a-axis oriented ZnO thin films are grown on (0 0 1) MgO substrates by pulsed laser deposition assisted by a very directional radio frequency oxygen plasma. The structure of the film is examined by X-ray diffraction, electron diffraction and high resolution electron microscopy. The film grows with vertical columns and is highly textured. Two preferential orientation relations between the ZnO film and the MgO substrate are observed: (1 0 ¯ 10) ZnO ||(002) MgO ; [0002] ZnO ||[200] MgO and (10 ¯ 10) ZnO || (002) MgO ;[ ¯ 12 ¯ 10] ZnO || [200] MgO . The film/substrate interface is flat and strained because of the rather large lattice mismatch between the (1 0 ¯ 1 0) plane of ZnO and the (0 0 2) plane of MgO. r 2005 Elsevier B.V. All rights reserved. PACS: 81.15.Fg; 61.10.Nz; 68.37.Np; 68.55.Jk Keywords: A1. Characterization; A3. Plasma assited laser deposition; B1. ZnO; B2. Piezoelectric materials 1. Introduction Zinc oxide (ZnO) is a wide band gap semicon- ductor (3.3 eV) with hexagonal wurtzite structure showing several outstanding physical properties for optical and electronic applications. ZnO has good photoconductivity, is transparent in visible and infrared and has a large exciton binding energy which enables the use of ZnO thin films for light emitting diodes and efficient UV lasers. With a large electro-mechanical coupling factor and a high piezoelectric coefficient, ZnO thin films are good candidates for high frequency and low loss surface acoustic wave (SAW) devices [1,2]. However, the electrical and optical properties of the films are critically dependent on their ARTICLE IN PRESS www.elsevier.com/locate/jcrysgro 0022-0248/$-see front matter r 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.jcrysgro.2004.12.162 Ã Corresponding author. Tel.:+40214930195; fax: +40214930257. E-mail address: leonis@infim.ro (L.C. Nistor).