Title: Fabrication of homogeneous nanoparticle/nanoneedle BaTiO₃ and Ba_0.8Sr_0.2TiO₃ smooth thin films by simple dip coating

Authors: Mamta Saini, K. Vivekanand, Pankaj Poddar, K.V.G.K. Murty, K.S. Thushara, Chinnakonda S. Gopinath

Addresses: Physical Chemistry Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India. ' Physical Chemistry Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India. ' Physical Chemistry Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India. ' AU-KBC Research Center, MIT Campus of Anna University, Chromepet, Chennai 600 044, India. ' Catalysis Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India. ' Catalysis Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India

Abstract: Ferroelectric BaTiO₃ (BTO) and Ba_0.8Sr_0.2TiO₃ (BSTO) thin film materials have been successfully prepared by sol-gel processing and simple dip coating on glass and silicon supports. Above thin films were characterised by x-ray diffraction (XRD), Raman spectroscopy, photoelectron spectroscopy, thermal analysis, atomic force microscopy (AFM) and spectroscopic ellipsometry. Phase identification of BaTiO₃ and Ba_0.8Sr_0.2TiO₃ was performed by XRD. XRD and Raman spectroscopy investigations demonstrate that the Ba_0.8Sr_0.2TiO₃ film exhibits tetragonal structure. AFM analysis demonstrates the elongated nanospherical particles on glass substrate and nanowires on silicon substrate, which represent a strong influence of the crystallinity of underlying substrate on the grain morphology in this technique. The thin films on both the substrates are uniformly coated without any pinhole to a significant area (~2.5 cm²), and this method might be extended to large area uniform coating. Spectroscopic ellipsometric measurements reveal the exact thickness, refractive index and extinction coefficient of the thin films.

Keywords: barium titanate; barium strontium titanate; thin films; nanotechnology; fabrication; dip coatings; ferroelectric materials; large area coating; thickness; refractive index; extinction coefficient; sol-gel; nanoparticles; nanowires; nanotechnology; crystallinity; grain morphology.

DOI: 10.1504/IJNT.2010.034698

International Journal of Nanotechnology, 2010 Vol.7 No.9/10/11/12, pp.919 - 931

Published online: 17 Aug 2010 *

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