Electrical investigation of TiO2 thin films coated on glass and silicon substrates—effect of UV and visible light illumination (original) (raw)
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Surface Morphology, Compositional, Optical and Electrical Properties of TiO2 Thin Films
Abstract: Titanium oxide (TiO2) thin films have been deposited on to glass substrate by spray pyrolysis deposition technique (SPDT). The surface morphological, structural, electrical and optical properties of the asdeposited TiO2 thin films have been investigated as a function of substrate temperature (Ts). The scanning electron micrographs of as-deposited films showed uniform surface of TiO2 thin films. Elemental analysis clearly showed that the grains were typically comprised of both Ti and O in the thin films. Strong diffraction peaks (101) and (200) at 25° and 48° respectively indicating TiO2 in the anatase phase .The peaks were found to shift slightly from their standard positions at higher Ts, and there was some deviation in the lattice parameters. The crystallite size is found to be around 13 nm. The optical transmission of the thin films was found to increase from 73 to 89 % and the band gap energy shifts from 3.64 to 3.40 eV with increase of Ts. The room temperature dc electrical resistivity varies from 42 to 27 ohm.cm for the thin films grown at different Ts.
Electrical Properties of Nano-TiO<sub>2</sub> Thin Film Using Spin Coating Method
Journal of Minerals and Materials Characterization and Engineering, 2014
This work investigated the electrical properties of TiO 2 thin film on empty glass and ITO glass by spin coating method. Highly transparent titanium oxide thin films were prepared on empty glass and Indium Tin Oxide (ITO) from a titanium (III) chloride precursor. The sheet resistance of the film prepared from both the synthesised and the commercially available TiO 2 was measured by the Keithley four-point probe tester (KFPPT). A comparable sheet resistance of 10.69E + 00 Ω/sq was obtained on the ITO. The electrical conductivity of the TiO 2 film on ITO glass substrate was found to be very high (3.46E + 05 Ω −1 ·cm −1 ) and comparable to that of the bare ITO glass.
Electrical Properties of Nano-TiO2 Thin Film Using Spin Coating Method
Journal of Minerals and Materials Characterization and Engineering, 2014
This work investigated the electrical properties of TiO 2 thin film on empty glass and ITO glass by spin coating method. Highly transparent titanium oxide thin films were prepared on empty glass and Indium Tin Oxide (ITO) from a titanium (III) chloride precursor. The sheet resistance of the film prepared from both the synthesised and the commercially available TiO 2 was measured by the Keithley four-point probe tester (KFPPT). A comparable sheet resistance of 10.69E + 00 Ω/sq was obtained on the ITO. The electrical conductivity of the TiO 2 film on ITO glass substrate was found to be very high (3.46E + 05 Ω −1 •cm −1) and comparable to that of the bare ITO glass.
The influence of annealing temperature on the structure, optical and electrical property of TiO 2 thin films with (101) preferential orientation were deposited on glass substrates by sol-gel technique has been studied. As-deposited films were amorphous, and the XRD studies showed that the formation of anatase phase was initiated at annealing temperature close to 400 °C. The grain size of the film annealed at 550 °C was about 22 nm. The transmission spectra, recorded in the UV visible range reveal a relatively high transmission coefficient (~70%) in the obtained films. The transmittance data analysis indicates that the optical band gap (E g ) is closely related to the annealing temperature, an indirect band gap ranging from 3.43 eV to 3.04 eV was deduced. The electrical resistivity measurement that were carried out in function of the annealing temperature showed a sharp decrease in resistivity was found to be 0.0802 .cm.
Electrical properties of TiO2 thin films
Journal of Non-Crystalline Solids, 2008
The electrical properties of n-type titanium dioxide thin films deposited by magnetron-sputtering method have been investigated by temperature-dependent conductivity. We observed that the temperature dependence of the electrical conductivity of titanium dioxide films exhibits a crossover from T À1/4 to T À1/2 dependence in the temperature range between 80 and 110 K. Characteristic parameters describing conductivity, such as the characteristic temperature (T 0), hopping distance (R hop), average hopping energy (D hop), Coulomb gap (D C), localization length (n) and density of states (N(E F)), were determined, and their values were discussed within the models describing conductivity in TiO 2 thin films.
Materials Research, 2016
Titanium dioxide (TiO 2) thin films were prepared by Chemical Bath Deposition (CBD) method. The X-ray diffraction (XRD) analysis was used to examine the structure and to determine the crystallite size of TiO 2 thin film. The surface morphology of the film was studied using Scanning Electron Microscopy (SEM).The optical properties were studied using the UV-Visible and photoluminescence (PL) spectrum. Optical constants such as band gap, refractive index, extinction coefficient and electric susceptibility were determined. The FT-IR spectrum revealed the strong presence of TiO 2. The dielectric properties of TiO 2 thin films were studied for different frequencies and different temperatures. The AC electrical conductivity test revealed that the conduction depended both on the frequency and the temperature. Photoconductivity study was carried out in order to ascertain the positive photoconductivity of the TiO 2 thin films.
AIP Conference Proceedings, 2017
Titanium dioxide (TiO2) thin films are deposited on silicon substrates by using sol-gel dip coating technique. Annealing temperature was varied to investigate its effect on the surface morphology, structural and electrical properties of the film. The crystalline structure, surface morphology and the electrical properties were investigated by X-ray diffraction, field emission scanning electron microscopy (FESEM), atomic force microscope (AFM), and four point probe. The results show that with an increase in annealing temperature, the value of the intensity of (101) peak increases while the value of the full-width at half maximum decreases. Thin films deposited at high annealing temperatures result in an increase in surface roughness and grain size. The electrical properties of these films show that the resistivity varies between 1.40 x 10 5 and 7.19 x 10 2 Ω.cm when the annealing temperature changes from 300 to 900°C, respectively. The TiO2 thin films annealed at 900°C exhibited lower resistivity than other films. It found that the annealing temperature influences the surface morphology, structural and electrical properties of TiO2 thin films.
AIP Conference Proceedings, 2010
Recently, ceramic metals (cermets) have been widely investigated for use as embedded resistor materials. In this study, SiO-Pt nano-composite cermets were developed to control the resitivity and temperature coefficients of resistance (TCR) of embedded thin film resistors. The SiO-Pt nanocomposite was prepared by the co-sputtering of a SiO x target and Pt chips onto glass. The experiments were conducted Pt concentrations in order to find the optimum conditions to achieve a high resistivity and low TCR. The electrical properties of the sputtered SiO-Pt thin films were investigated by probe station and their crystal structures were observed by X-Ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). The surface morphology was observed by field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM). It was found that the Pt particles with a size of 3∼5 nm were uniformly dispersed in the SiO matrix. A stable resistivity value of 26000∼57000 •cm and TCR value of −197∼−322 ppm/K were obtained at 3.5∼3.7 at.% Pt.
International Journal of Integrated Engineering, 2011
Fabrication of titanium dioxide (TiO 2) thin film on microscope glass using sol-gel method has been studied intensively. The starting materials were titanium (IV) butoxide, ethanol, acetic acid, triton x-100, hydrochloric acid and deionized water. The materials were mixed together to form the sols. Then, the heat and ageing treatment was applied to form stable sols. The sols were then spin coated on the glass substrate to form the homogenous and transparent TiO 2 thin film. The TiO 2 thin film was coated at several layers using specific conditions. To evaluate the performance of thin film, the crystallinity of the thin film was determined by using the x-ray diffractometer (XRD). The change on the surface morphology was observed using atomic force microscope (AFM). The electrical property of the thin film was determined by doing the current-voltage (I-V) analysis on the thin film. It has been successfully shown that the anatase crystalline phase was observed when the TiO 2 thin film was heated at 500°C. The roughness and the crystalline phase of TiO 2 thin film changed drastically with the growth conditions. Finally, the effect of film preparation to the film resistivity also showed a critical aspect where we should take into account during the preparation of TiO 2 thin film.
Preparation and Characterization of TiO 2 and SiO 2 Thin Films Open Access
scirp.org
Although scaling will continue for couple of decades but device geometries reaches to atomic size and limitation of quantum mechanical physical boundaries. To address these problems there is need of innovation in material science & engineering, device structure, and new nano devices based on different principle of physics. So TiO 2 thin films have been grown on well clean N-type silicon substrates via a sol-gel spin coating method. MOS capacitor were fabricated and characterized with SiO 2 and TiO 2 as dielectric material on N-type silicon wafer. The thickness was measured by stylus profiler and found to be 510 Å and 528 Å for SiO 2 and TiO 2 respectively. Some of the material parameters were found from the measured Capacitance -Voltage (C-V) curve obtained by SUPREM-III (Stanford University Process Engineering Model Version 0-83) for SiO 2 and C-V Keithly 590 analyzer for TiO 2 thin films. The result shows that obtained TiO 2 film present a dielectric constant of approximately 80. The refractive index was found to be 2.4 and optical constant was 5.43 obtained from Ellipsometry. Band gap 3.6 eV of TiO 2 was calculated by spectrophotometer and Surface morphology was obtained using Scanning Electron Microscope (SEM-JEOL) micrograph. The aluminum (Al) metal was deposited by the thermal evaporation system on the back side of the sample for the ohmic contact. Analysis shows that TiO 2 may be acceptable as a viable substitute for high k dielectric in order to prevent the tunneling current problems.