Atomic Force Microscopy Study of TiO2 Films Obtained by the Sol-Gel Method
ABSTRACT Atomic Force Microscopy (AFM) was used to study the influence of thermal treatments on the structural and textural properties of the sol-gel TiO2 films obtained from Ti(OC3H7i)4. X-ray diffraction (XRD), ellipsometric and porosity measurements have also been made.The TiO2 sol-gel films were homogeneous, transparent and amorphous. Heat treatments in the 400–600C range indicate that the films have a strong tendency to crystallization. The high initial homogeneity of the TiO2 films was preserved during the crystallization process. AFM shows that the thermally treated films exhibit uniform, monodispersed crystals.
- SourceAvailable from: Suzana Šegota
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- "Atomic force microscopy (AFM) is a very important tool for examining the thin film surface morphology at the nanoscale. During the last decade, a considerable interest has been expressed regarding the application of AFM for structural studies of different materials   . "
ABSTRACT: The application of heterogeneous photocatalysis is described as an advanced oxidation process (AOP) for the degradation of the diazo reactive dye using immobilized TiO2 as a photocatalyst. Starting TiO2 solutions were prepared with and without the addition of polyethylene glycol (PEG) and TiO2 films were directly deposited on a borosilicate glass substrate using the sol–gel dip-coating method. The surface morphology and the nanoscale roughness of TiO2 films were studied by means of atomic force microscopy (AFM). Structural properties of TiO2 were identified by X-ray diffraction (XRD). The decomposition behaviour of organic compounds from the gels was investigated using thermal gravimetry (TG) and differential scanning calorimetry (DSC). Photocatalytic activities of TiO2 films in the process of degradation of the commercial diazo textile dye Congo red (CR), used as a model pollutant, were monitored by means of UV/vis spectrophotometry. The kinetics of the degradation of the CR dye was described with the Langmuir–Hinshelwood (L–H) kinetic model.The addition of PEG to the TiO2 solution resulted in the changes in the film surface morphology, and affected the ratio of anatase–rutile crystal phases and the photocatalytic activity of TiO2. The TiO2 film prepared with PEG is characterized by higher roughness parameters (Ra, Rmax, Rq, Rz and Zmax), a lower amount of the rutile phase of TiO2, a higher amount of the anatase phase of TiO2 and a better photocatalytic activity compared to the TiO2 film without the addition of PEG.Ceramics International 05/2011; 37(4):1153-1160. DOI:10.1016/j.ceramint.2010.10.034 · 2.09 Impact Factor
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- "Titanium oxide TiO 2 has universally been recognized as one of the better photocatalysts in heterogeneous photocatalysis applications as it combines two important complementary features for a photocatalyst: good UV absorption efficiency for the light harvesting process and good adsorption capacities, due particularly to the density of OH – groups of amphoteric character. However, the band gap energy requires that near-UV light be used to photo activate this very attractive photocatalyst   . "
ABSTRACT: Transparent iron-doped titanium oxide thin films were prepared on soda-lime-silica glass substrate from a titanium naphthenate precursor. Films prefired at 500°C for 10 min were finally annealed at 500°C for 30 min in air. Field emission–scanning electron microscope and scanning probe microscope were used for characterizing the surface structure of the film. A sharp absorption edge of the film was observed. The film containing iron showed a shift towards the visible in the absorption threshold.
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ABSTRACT: The capacitance–voltage–temperature (C–V–T) and the conductance/angular frequency–voltage–temperature (G/ω–V–T) characteristics of Au/TiO2(rutile)/n-Si Schottky barrier diodes (SBDs) were investigated over the temperature range from 200 K to 380 K by considering the series resistance effect. Titanium dioxide (TiO2) was deposited on n-type silicon (Si) substrate using a direct-current (DC) magnetron sputtering system at 200°C. To improve the crystal quality, the deposited film was annealed at 900°C to promote a phase transition from the amorphous to rutile phase. The C −2 versus V plots gave a straight line in the reverse-bias region. The main electrical parameters, such as the doping concentration (N D), Fermi energy level (E F), depletion layer width (W D), barrier height (ф CV), and series resistance (R S), of Au/TiO2(rutile)/n-Si SBDs were calculated from the C–V–T and the G/ω–V–T characteristics. The obtained results show that ф CV, R S, and W D values decrease, while E F and N D values increase, with increasing temperature.Journal of Electronic Materials 06/2013; 42(6). DOI:10.1007/s11664-013-2524-0 · 1.68 Impact Factor