Synthesis and characterization of nanostructured TiO2 and TiO2/W thin films deposited by co-sputtering

Abstract

Nanostructured TiO 2 and TiO 2 /W thin films were deposited on Corning glass substrates by RF and DC magnetron co-sputtering at room temperature, using three targets of TiO, Ti and W. After deposition, samples were subjected to an annealing treatment in air at 500 °C for 3 hrs. The effect of the annealing treatment and tungsten addition to the TiO 2 matrix were studied by Raman spectroscopy and X-ray diffraction. Morphology and composition was studied with field emission scanning electron microscopy and optical characterization was made with UV-Vis spectroscopy. All the obtained samples presented an amorphous TiO 2 phase; however, after the annealing treatment, a crystallization process from amorphous to anatase phase occurred with gain sizes between 15.6 and 18.3 nm, additionally, a small amount of rutile was also observable. The SEM images corroborated the XRD behavior, besides it was possible to calculate the thickness of the films which was greater for the W-doped films owing the extra power of the sputtering growth, and after the samples had the thermal treatment the thickness decreased due to a more organized structure. Finally, the UV-vis transmittance analysis revealed that the transmittance is higher in heat-treated films as compared to those without any thermal treatment; also, the TiO 2 thin films showed a greater transmittance than the W doped TiO 2 films, reaching 91%. The lack of transmittance in the non-thermal-treated films made it impossible to compute the band gap of the films; nevertheless, for the thermal-treated films the band gap had a minimal change to the classic TiO 2 bang gap value, even for the W doped sample, providing them with the benefits of the tungsten within the same TiO 2 structure due to a great homogenization on the structure.

Synthesis and Charactization of Titanium Dioxide Papered by Spray Pyrolysis as No2 and H2s Gas Sensor

“…Figure (1) displays the thin film XRD patterns that were produced by typical spray pyrolysis. the samples were prepared on glass substrate at temperature 400ºC ,30cm distance between spray head and substrate and The scans were performed over 2ɵ = 10º -90º .…”

“…Gas se nsors are e ssential in the de tection, monitoring, and control of dange rous and de adly gases that can e xist in the atmosphe re at ve ry low quantitie s. Thin -film se miconductor gas se nsors are e xtre me ly se nsitive and trustworthy, with a pe rformance/price ratio similar to that of microe le ctronic compone nts. Due to the ir be ne ficial characte ristics, such as a wide bandgap approximate ly 3.2 e V, a low re sistance, and good catalysis, titanium dioxide (TiO2) se miconductive materials have been investigated intensively as che mical sensors for a long time [1]. Due to the ir high e lectric conductance, great transparency to visible light, and strong contact with the gas molecules, TiO 2 nanostructures e xhibit high gas se nsing re sponse.…”

First principles study of the electronic and optical properties of high‐valence transition metal‐doped anatase titanium dioxide

“…In other works, tantalum-doped titanium dioxide films were used as the electron transport layer to enhance the performance of perovskite solar cells because of its high electronic conductivity and optical transparency in the visible range [16][17][18]. In addition, some efforts have been undertaken to explore the electrical, optical and photocatalytic properties of hexavalent tungsten and molybdenum ion doped titanium dioxide films [19][20][21][22][23][24]. Density functional theory calculation is a powerful and fundamental tool to reveal the internal mechanism of photoelectric behavior of semiconductor materials.…”