TiO2 anatase films obtained by direct liquid injection atomic layer deposition at low temperature (original) (raw)
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Synthesis and characterization of anatase-TiO2 thin films
Applied Surface Science, 2005
A new and effective method for the preparation of nanocrystalline TiO 2 (anatase) thin films is presented. This method is based on the use of peroxo-titanium complex as a single precursor. Post-annealing treatment is necessary to convert the deposited amorphous film into TiO 2 (anatase) phase. The films obtained are uniform, compact and free of pinholes. A wide range of techniques are used for characterization, namely X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDAX) and UV-Vis-NIR spectrophotometer. Glass, indium-doped tin oxide (ITO) and quartz are used as substrates. TiO 2 (anatase) phase with (1 0 1) preferred orientation is obtained for the films. Byproduct (collected powder) consists of the same crystal structure. The optical measurement reveals the indirect bandgap of 3.2 eV.
The Effect of Substrate on TiO2 Thin Films Deposited by Atomic Layer Deposition (ALD)
Advanced Materials Research, 2015
ALD is a precision growth technique that can deposit either amorphous or polycrystalline thin films on a variety of substrates. The difference in substrate can cause a variation in the ALD process, even it is carried out using the same reactants and deposition conditions [1]. TiO2thin films were grown using TTIP (Titanium isopropoxide) ALD on silicon wafers, glass slides, and stainless steel plates in order to study the effect of substrates on the growth of TiO2with 3,000 deposition cycles, at 300°C.The thin films were analyzed using Xray Diffraction (XRD), Raman Spectroscopy, Atomic Force Microscope (AFM) and Spectroscopic Ellipsometer. From XRD analysis were indicates the main peak for anatase (101) (2θ= 25.3) was observed from the XRD patterns for TiO2on all substrates. The results show that crystalline TiO2thin films can easily grow on a crystal substrate rather than on an amorphous substrate.
Effect of solution composition on anatase to rutile transformation of sprayed TiO2 thin films
Thin Solid Films, 2015
Acetylacetone is used as a chelating agent for titanium(IV) isopropoxide to inhibit hydrolysis and stabilize the precursor solution. The effect of the molar ratio between titanium(IV) isopropoxide and acetylacetone of 1:1, 1:2, 1:3 and 1:4 in the precursor solution on the morphological, structural and optical properties of TiO 2 thin film was investigated. These properties were studied using Fourier transformed infrared spectroscopy, scanning electron microscopy, Raman spectroscopy, X-ray diffraction and UV-vis spectroscopy as a function of the molar ratios for the as-deposited thin films and films annealed at temperatures of 700, 800 and 950°C. Mixed anatase and rutile phases were detected after annealing at 800°C for 1:1 and 1:2 molar ratios and at 700°C for 1:3 and 1:4 molar ratios. The optical band gap decreased from 3.45 to 3.02 eV with an increase in the annealing temperature in agreement with corresponding structural changes.
Preparation of Anatase TiO2Thin Films with (OiPr)2Ti(CH3COCHCONEt2)2Precursor by MOCVD
Bulletin of the Korean Chemical Society, 2004
The reaction of titanium tetraisopropoxide with 2 equiv of N,N-diethyl acetoacetamide affords Ti(O i Pr) 2 (CH 3 COCHCONEt 2) 2 (1) as colorless crystals in 80% yield. Compound 1 is characterized by spectroscopic (Mass and 1 H/ 13 C NMR) and microanalytical data. Molecular structure of 1 has been determined by a single crystal X-ray diffraction study, which reveals that it is a monomeric, cis-diisopropoxide and contains a six coordinate Ti(IV) atom with a cis(CONEt2), trans(COCH3) configuration (1a) in a distorted octahedral environment. Variable-temperature 1 H NMR spectra of 1 indicate that it exists as an equilibrium mixture of cis, trans (1a) and cis, cis (1b) isomers in a 0.57 : 0.43 ratio at −20 o C in toluene-d 8 solution. Thermal properties of 1 as a MOCVD precursor for titanium dioxide films have been evaluated by thermal gravimetric analysis and vapor pressure measurement. Thin films of pure anatase titanium dioxide (after annealing above 500 o C under oxygen) have been grown on Si(100) with precursor 1 in the substrate temperature range of 350-500 o C using a bubbler-based MOCVD method.
Microstructure and elastic properties of atomic layer deposited TiO2 anatase thin films
Acta Materialia, 2011
Amorphous TiO 2 thin films were deposited by means of atomic layer deposition on Kapton substrates and then crystallized ex situ by annealing at 300°C to obtain the anatase phase. The morphology, structure and microstructure of films treated for 12, 24, 72 and 90 h were investigated. The local Ti coordination changes were studied by X-ray near-edge structure (XANES).
Highly Reactive TiO2 Anatase Single Crystal Domains Grown by Atomic Layer Deposition
Crystal Growth & Design, 2018
Anatase TiO 2 films with unusual domains-like morphology were obtained by post-deposition annealing of amorphous TiO 2 films deposited by Atomic Layer Deposition (ALD). Such particular morphology was observed only for TiO 2 films deposited using TiCl 4 precursor in a non-conventional ALD regime where the reaction by-products or non-reacted precursors are incorporated into the film and induce an explosive recrystallization upon
Journal of Materials Chemistry, 2002
Micropatterning of anatase TiO 2 thin films by site-selective immersion was realized using a self-assembled monolayer (SAM) which has a pattern of hydrophilic and hydrophobic surfaces. A solution containing a Ti precursor contacted the hydrophilic surface during the experiment and briefly came into contact with the hydrophobic surface via our newly developed method. The solution on the hydrophilic surface was replaced with a fresh solution by the continuous movement of bubbles. Thus TiO 2 was deposited and a thin film was grown selectively on the hydrophilic surface. A TiO 2 thin film fabricated by the site-selective immersion method has no cracks and the feature edge acuity of its micropattern was much higher than that of the micropattern obtained by the lift-off process.
Thin Films of Titanium Dioxide Prepared by Chemical Routes using Novel Precursors
MRS Proceedings, 2002
ABSTRACTNovel, volatile, stable, oxo-β-ketoesterate complexes of titanium, whose synthesis requires only an inert atmosphere, as opposed to a glove box, have been developed. Using one of the complexes as the precursor, thin films of TiO2 have been deposited on glass substrates by metalorganic chemical vapor deposition (MOCVD) at temperatures ranging from 400°C to 525°C and characterized by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. All the films grown in this temperature range are very smooth; those grown above 480°C consist of nearly monodisperse, nanocrystals of the anatase phase. Optical studies show the bandgaps in the range 3.4–3.7 eV for films grown at different temperatures. Thin films of anatase TiO2 have also been grown by spin-coating technique using another ketoesterate complex of titanium, demonstrating that the newly developed complexes can be successfully used for thin film growth by various chemical routes.
Materials Sciences and Applications, 2011
Titanium dioxide thin films were deposited on (0001) -quartz substrate by spray pyrolysis method. The method which an aerosol of Titanium Butoxide, generated ultrasonically, was sprayed on the substrate at temperature of 400˚C, kept at this temperature for periods of 3, 13, 19 and 39 hours. The developed films at a crystal phase correspond to the TiO 2 anatase and rutile phases. Their surface roughness increased by annealing the samples at 600, 800 and 1000˚C. Deposited film annealed at 1000˚C showed preferable orientation in (110) direction. The crystal evolution and crystallographic properties of this material was studied by Lotgering method, X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The study revealed that the deposition process was nearly close to the classical Chemical Vapour Deposition (CVD) technique that is generally employed to produce films with smooth surface and good crystalline properties with a thickness of about 1 µm, as measured by Focused Ion Beam.