Spatial profile of Al-ZnO thin film on polycarbonate deposited by ring-shaped magnetized rf plasma sputtering with two facing cylindrical Al2O3 - ZnO targets

Radial profiles of the ion saturation current are measured in a ring-shaped magnetized radio-frequency plasma sputtering process with two facing cylindrical ZnO targets including Al2O3 (2% wt.). The profile has a non-uniform shape with a peak whose position corresponds to the target near the electrode due to the effect of the magnetic field distribution. It becomes uniform at large distances between the substrate and a target (d st ≥ 50 mm). The radial profile of the resistivity of the Al-ZnO (AZO) films deposited on a polycarbonate plate at Ar gas pressure of 0.27 Pa is uniform at about 10-3 Ω·cm for d st ≥ 50 mm. The films deposited at various positions and room-substrate-temperature also show a good crystallinity based on an X-ray diffraction peak of about 33.95 - 34.44°. The grains exhibit a preferential orientation along the [002] axis with its size ranging from 18.15 to 28.17 nm. A higher transmittance of 95.6 % in the visible region is also obtained.

Fabrication of Novel Chitosan–Hydroxyapatite Nanostructured Thin Films for Biomedical Applications

In this study, we develop chitosan–hydroxyapatite (CS–HAp) composite layers that were deposited on Si substrates in radio frequency (RF) magnetron sputtering discharge in argon gas. The composition and structure of CS–HAp composite layers were investigated by analytical techniques, such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), metallographic microscopy (MM), and atomic force microscopy (AFM). On the other hand, in the present study the second order derivative of FT-IR–ATR spectra, for compositional analyses of CS–HAp, were used. The SEM, MM, and AFM data have shown the formation of CS–HAp composite layers. The surface of CS–HAp composite layers showed uniform growth (at an Ar gas working pressure of p = 2 × 10−3 mbar). The surface of the CS–HAp composites coatings became more nanostructured, becoming granular as the gas pressure increased from 5 × 10−3 to 1.2 × 10−2 mbar. However, our studies revealed that the surface morphology of the CS–HAp composite layers varies with the Ar gas working pressure. At the same time, optical properties are slightly influenced by Ar pressure. Their unique physicochemical properties make them suitable for various applications in the biomedical field, if we consider the already proven antimicrobial properties of chitosan. The antifungal properties and the capacity of the CS–HAp composite layers to inhibit the development of fungal biofilms were also demonstrated using the Candida albicans ATCC 10231 (C. albicans) fungal strain.

Pulse-Modulated Plasma Etching of Copper Thin Films via CH3COOH/Ar

Pulse-modulated plasma etching of copper masked using SIO2 films was conducted via a CH3COOH/Ar. The etch characteristics were examined under pulse-modulated plasma. As the duty ratio of pulse decreased and the frequency of pulse increased, the etch selectivity and etch profile were improved. X-ray photoelectron spectroscopy and indicated that more copper oxides (Cu2O and CuO) and Cu(CH3COO)2 were formed using pulse-modulated plasma than those formed using continuous-wave (CW) plasma. As the concentration of CH3COOH gas in pulse-modulated plasma increased, the formation of these copper compounds increased, which improved the etch profiles. Optical emission spectroscopy confirmed that the active ingredients of the plasma increased with decreasing pulse duty ratio and increasing frequency. Therefore, the optimized pulsed plasma etching of copper via a CH3COOH/Ar gas provides better etch profile than that by CW plasma etching.

Appling the computational fluid dynamics studies of the thermogravitational column for N2-CO2 and He-Ar gas mixtures separation

In the present work, three-Dimensional stationary numerical simulations were accomplished for a deeper understanding of the gas mixtures separation by the thermogravitational column. To address the optimum condition and examine the limitation of the process, the thermogravitational column behavior has been thoroughly analyzed. First, the simulation model was validated by the experimental results of Youssef et al. then the model was developed for the pilot column. The mixture of helium-argon was chosen as feed composition. It was concluded that the variation of the separation factor in relation to pressure for both columns was almost the same. The optimum condition verified as p = 0.2 atm , θ = 0.4 , m ° = 4 SCCM $p=0.2\text{atm},\theta =0.4,m{\degree}=4\,\text{SCCM}$ .

Influence of Ar Gas Pressure On The Structural And Optical Properties And Surface Topography of Al-Doped ZnO Thin Films Sputtered By DC-Magnetron Sputtering Method

In this work, Aluminum doped Zinc oxide thin films were sputtered on glass substrate by the direct current (DC) magnetron sputtering method. The influence of Ar gas pressure on the structural and optical properties was measured. The optical parameters were calculated by UV- Visible spectroscopy, the nature of transition reveals direct allowed transition for the prepared films. Also, some physical quantities such as the strength of electron-phonon interaction, dissipation factor (tanδ) in the visible region and the lattice dielectric constant were presented for these thin films. The AFM analysis extracts surface parameters of the AZO thin films that help us to investigate the surface analysis with numerical data. The band gap energy and transition index without any presumption about transition natural were calculated from Derivation Ineffective Thickness Method (DITM) and the reaction of Ar gas pressure plays an essential part in controlling the physical quantities of AZO thin films.

Experimental and theoretical study of the characteristics of LSPR peaks for metal NPs produced by controlling Ar ambient gas pressure to enhance the efficiency of solar cells

In this study, silver (Ag) nanoparticle thin films were deposited on microscope slide glass and Si wafer substrates using the pulsed-laser deposition (PLD) technique in Ar ambient gas pressures of 1 × 10−3 and 7.5 × 10−1 mbar. AFM analysis has shown that the number of Ag nanoparticles reaching the substrate decreased with increasing Ar gas pressure. As a result of Ar ambient gas being allowed into the vacuum chamber, it was observed that the size and height of Ag nanoparticles decreased and the interparticle distances decreased. According to the absorption spectra taken by a UV–vis spectrometer, the wavelength where the localised surface plasmon resonance (LSPR) peak appeared was shifted towards the longer wavelength region in the solar spectrum as Ar background gas pressure was decreased. This experiment shows that LSPR wavelength can be tuned by adjusting the size of metal nanoparticles, which can be controlled by changing Ar gas pressure. The obtained extinction cross section spectra for Ag nanoparticle thin film was theoretically analysed and determined by using the metal nanoparticle–boundary element method (MNPBEM) toolbox simulation program. In this study, experimental spectrum and simulation data for metal nanoparticles were acquired, compared, and determined to be in agreement.