Papers by Keyword: DC Sputtering

Abstract: Titanium Nitride coating has attracted much interest in increasing the hardness of aluminum alloys. This study aims to investigate the effect of Ar: N gas mixture and time on increasing the hardness of aluminum alloys using DC sputtering. Preparation of TiN thin films on aluminum alloy substrates using flowing gas mixture parameters and time. First, the layer of TiN was deposited on the sample with a gas mixture of 90Ar:10N; 80Ar:20N; 70Ar:30N; and 60Ar:40N (%) for 60 minutes. Then the optimum gas mixture that produces the highest surface hardness is used in the second process with time variations of 30, 60, 90, and 120 minutes. The results showed that the highest hardness was achieved in a gas mixture of 70Ar:30N and 60 minutes. The TiN phase formed on the aluminum surface was identified by XRD, while the surface morphology was observed by SEM. Compared with untreated samples, the hardness of treated samples increased significantly.

Abstract: Tungsten Sulfide (WS₂) has been appeared as visible range semi-conductors with having substantial direct band gap. In two-dimensional (2D) transition metal dichalcogenides (TMDC) i.e.WS₂ has been growing research attention over more than the past twenty years in low cost, energy-efficient, adaptable or environment-friendly material, which is crucial part of optoelectronic emission devices. WS₂ semiconductor thin films were grown on glass and Si substrates by using DC sputtering method. During deposition the substrate were kept at temperature of 200°C. The thin films were studied by X-ray diffraction, UV-Vis spectrometry and Spectrofluorometer (FS5). XRD analysis revealed the nature of grown film effected by temperature of substrate results in to be amorphous. Photoluminescence analysis at 532nm and optical study proved the direct to indirect band transition in WS₂.

Abstract: Aluminum is a lightweight material that is commonly used in engine components. However, aluminum's low hardness and wear resistance, requires special treatment before being used as a component. Increasing the hardness and wear resistance of aluminum can be done by coating Titanium Nitride (TiN) with the sputtering method. In this study, the effect of sputtering time on Al-TiN coating on hardness and wear resistance was obtained. The deposition of titanium nitride thin films on aluminum using a gas ratio of Ar: N ((70:30%) with varied treatment times of 30, 60, 90, and 120 minutes. Hardness and wear resistance were observed using Vickers hardness tester and Ogoshi High-Speed Universal. Whereas the morphology of the wear surface was observed by SEM. The result shows that the treatment time of 60 minutes obtained the highest hardness and minimum specific wear rate.

Abstract: Nb₂O₅ is one of the most favorable transparent conducting oxide materials, which is efficiently used in thin film gas sensors especially for reducing gases. In this research, Al-doped Nb₂O₅ thin films on glass substrates with the DC plasma sputtering method for sensing NH₃ and NO₂ gases. The effect of thermal oxidation time on morphological, structural properties, and gas sensing properties of Nb₂O₅: Al thin films are investigated. Annealing was performed at 450 ° C for two hours. The results of X-ray diffraction (XRD) revealed that the structures are amorphous. Surface topography and growth behavior of Al-doped Nb₂O₅ thin films have an essential role in the optimization of gas sensing properties of these films. Also, atomic force microscopy (AFM) has been used to investigate the surface topography of the obtained films. Obtained results from these analyzes revealed that the films have monoclinic phase and surface topography of Nb₂O₅:Al thin films affected by Al-doped, the roughness and grain size of the surface increased with the increase in the Al content. Also, the effect of Al-doped on the performance of Nb₂O₅ thin films gas sensors is investigated. The results indicated that the best response was Nb₂O₅ film of NH₃ gas and Nb₂O₅:1%Al of NO₂ gas.

Abstract: New transparent conducting oxide (TCO) materials, indium-gallium-zinc-oxide (IGZO) and indium-tin-zinc-oxide (ITZO) were deposited on glass substrate by DC co-sputtering using IZO-GZO and IZO-ITO target combinations, respectively. Amorphous indium-gallium-zinc-oxide (a-IGZO) films possessing electron mobility of as high as 12 cm²V^-1s^-1 and resistivity of 0.15Ω・cm could be deposited. Hall mobility was ten times higher than that of amorphous silicon (a-Si), and comparable to that of commercial IGZO thin films. A good electrical resistivity of 0.17Ω・cm with a relatively high mobility of 10 cm²V^-1s^-1 was found for the ITZO films. These values were similar to those observed for the IGZO films in the present study.

Abstract: Tungsten oxide (WO₃) electrochromic thin films were deposited onto F-doped tin oxide (FTO) substrates using DC sputtering of tungsten target in presence of oxygen and argon gas. As-deposited films were prepared with different sputtering power at 50 W, 100W and 200W. The effect of power on structural, surface morphology optical and electrochromic properties of the WO₃ thin films were characterized by X-ray diffractometer, scanning electron microscope, UV-VIS spectrophotometer and Cyclic voltammetry, respectively. The XRD results show that the crystalline of WO₃ can be identified an orientation growth along (222) plane. The average grain size evaluated from SEM image is approximately 200 nm. The films deposited at power of 200 W exhibited better electrochromic properties with greatest optical modulation (∆T) value of ∆T = 31.2 % at l= 550 nm. The cyclic voltammograms (CV) of WO₃ thin films evidently exhibited that the WO₃ films prepared at power of 200 W displayed the superior electrochromic performance, compared to the others.

Abstract: Recently both, electrical and material properties of tantalum oxide (Ta₂O₅) have been found to be useful for microelectronics and optoelectronics devices. The need of higher permittivity of dielectric material attracts more attention towards the tantalum oxide thin films. To ensure good electrical performance of the resulting device DC sputtering technique has been used for depositing Ta₂O₅ films. In the present work, the potential of Ta₂O₅ thin films as a high K dielectric for CMOS devices has been studied. Physical characteristics of the Ta₂O₅ dielectrics were investigated with x-ray diffraction and electrical properties were measured by capacitance-voltage (C-V) analysis. The interface state density of 1* 10 ¹¹ cm^-2 eV^-1 have been achieved for 50 nm Ta₂O₅ film. The calculated value of dielectric constant of as deposited Ta₂O₅ oxide film was found to be 29. This Ta₂O₅ dielectric shows promise for future generation of CMOS devices.

Abstract: Metal oxynitride (V_xON, Cr_xON) thin film has been fabricated by reactive dc sputtering method and annealing process. Its electrochemical properties are investigated in a M_xON/Li cell. The reversible specific capacities are around 830 mAh g^-1 for V_xON and 730 mAh g^-1 for Cr_xON. By using selected-area electron diffraction and X-ray photoelectron spectroscopy measurements, New electrochemical reaction mechanism is uncovered, which should be responsible for its good electrochemical performance.

Abstract: Nitrogen-doped titanium oxide (N-TiO₂) films deposited on unheated glass slides at various flow rates of N₂ in an atmosphere of Ar and O₂ gas mixture by direct current sputtering technique were investigated. The Ti2p, O1s and N1s spectra by X-ray photoelectron spectroscopy (XPS) verified N-substitution into TiO₂ lattice which is responsible for the band gap narrowing. The oxygen total ratio (r_OT) in the gas mixture had profound influence on the photocatalytic properties of the N-doped films. At a ratio of r_OT≦0.18, heterogeneous phases, such as titanium oxynitride (TiN_xO_y) and titanium nitride (TiN), with low crystallinity were formed in the TiO₂ lattice, showing low photocatalytic activity. On the other hand, the N-TiO₂ films prepared at r_OT≧0.20 were found to have improved photocatalytic activity on methylene blue degradation under visible-light irradiation at wavelengths longer than 500 nm, due to the substitutional N ions in the TiO₂ lattice.

Abstract: The optimal process conditions for preparing nitrogen-doped titanium oxide (N-TiO2) films on unheated glass slides were investigated at various nitrogen (N2) flow rates. Films were found to exhibit significant polycrystalline structure, mainly the anatase phase with pyramid-like surface morphology. The X-ray photoelectron spectroscopy spectra confirmed the presence of the N2 within the TiO2 crystal lattice, resulting in a narrower band gap and in a red shift of the absorption into the visible-light region. N-doping of the TiO2 crystal lattice changed the oxidation state of Ti from Ti+4 to Ti+3, resulting in the formation of titanium oxynitride (TiOxNy) in the films. Our films displayed an enhanced ability to degrade a methyl blue solution illuminated with visible-light at wavelengths up to 500 nm. Among the samples tested, the N-TiO2 film that was deposited at a flow rate of 25 sccm N2 was found to be the most active photocatalyst.