Phase transformation of nanostructured titanium dioxide thin films grown by sol–gel method

• Published in: Applied physics. A, Materials science & processing Vol. 107; no. 1; pp. 233 - 241
• Main Authors: Sönmezoğlu, Savaş, Çankaya, Güven, Serin, Necmi
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.04.2012; Springer
• Subjects: Characterization and Evaluation of Materials; Cold working, work hardening; annealing, quenching, tempering, recovery, and recrystallization; textures; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Machines; Manufacturing; Materials science; Materials synthesis; materials processing; Nanotechnology; Optical and Electronic Materials; Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Physics and Astronomy; Processes; Solid-solid transitions; Specific phase transitions; Surfaces and Interfaces; Thin Films; Treatment of materials and its effects on microstructure and properties; Sol–gel method; Anatase-to-rutile phase transformation; Nanostructured titanium dioxide; Grain size; Atomic force microscopy; Annealing; Inorganic compounds; Phase transformations; Transition element compounds; Roughness; Annealing temperature; XRD; Nanostructures; Thin films; Optical properties; Dip coating; Microstructure; Titanium oxide; Sol-gel process
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-011-6749-6

Nanostructured TiO 2 thin films were deposited on quartz glass at room temperature by sol–gel dip coating method. The effects of annealing temperature between 200 ∘ C to 1100 ∘ C were investigated on the structural, morphological, and optical properties of these films. The X-ray diffraction results showed that nanostructured TiO 2 thin film annealed at between 200 ∘ C to 600 ∘ C was amorphous transformed into the anatase phase at 700 ∘ C, and further into rutile phase at 1000 ∘ C. The crystallite size of TiO 2 thin films was increased with increasing annealing temperature. From atomic force microscopy images it was confirmed that the microstructure of annealed thin films changed from column to nubbly. Besides, surface roughness of the thin films increases from 1.82 to 5.20 nm, and at the same time, average grain size as well grows up from about 39 to 313 nm with increase of the annealing temperature. The transmittance of the thin films annealed at 1000 and 1100 ∘ C was reduced significantly in the wavelength range of about 300–700 nm due to the change of crystallite phase. Refractive index and optical high dielectric constant of the n -TiO 2 thin films were increased with increasing annealing temperature, and the film thickness and the optical band gap of nanostructured TiO 2 thin films were decreased.