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This work aims to study Cu films, and Cu-Co bilayer deposited using DC Magnetron sputtering system on silicon substrates. It can be seen that as the thicknesses of films were increased, the grain s...

The purpose of this work is to investigate the optical constants of ZnO films doped by Cu, Al, and Cu-Al nanoparticles. The reflectance and the transmittance spectra measurements were applied for calculating these optical constants in the range of 200–2500 nm. It can be seen that ZnO films doped with Al nanoparticles have a maximum value nanoparticles size of about 23.73 nm. With increasing annealing temperature for all wavelength range, due to the improvement of crystalline structure and hence decreasing defects, the extinction coefficient of films decreased. The theoretical extrapolation of e1 versus λ2 at low wavelengths values provides the dielectric constant e∞ and for the ZnO films doped with Cu nanoparticles, it has a maximum value of 4.61. The ZnO films doped by Al nanoparticles have a minimum value of $${\chi }_{c}$$ in all energy range. The dissipation factor tan δ of ZnO films doped by Cu nanoparticles especially in high energy has a maximum value. SEL functions in ZnO films doped by Cu nanoparticles have the maximum value.

In this article, the Ni-Cu nanoparticles (NPs) in the amorphous carbon hydrogenated thin films with different copper percentage by co-deposition of RF-plasma enhanced chemical vapor deposition were prepared using acetylene gas and Ni and Cu targets. The films deposited with 5% Cu have minimum value of the average diameter of Multi-walled Carbon Nanotubes, MWCNTs, in about of 100 nm. It can be seen that the lateral size values of the nanoparticles for films with 5% Cu have minimum value of 5.34 nm. Films deposited with 75% Cu have maximum value of optical density specially in high energy. The spectral density power of all films indicated the presence of fractal components in prominent topographies. Films deposited without Cu NPs have minimum value of fractal dimension in about of 2.96. The diagram of the bearing area versus the nanoparticles height has shown the percentage of cavities and single-layers. The single-layer contents of all films were about 95%.

The sputtered copper nanoparticles (Cu NPs) on amorphous hydrogenated carbon films (CuNPs@a-C:H) were deposited on a glass substrate by the codeposition method of radio-frequency (RF)-sputtering an...

In this paper, a Zn - Cu mosaic target was used for fabricating of copper doped ZnO films using RF magnetron co-sputtering with oxygen and argon gases in room temperature. After the deposition of c...

In this article, a mosaic target made of ZnO and Al-Cu atoms were used for fabricating of the Cu-Al doped zinc oxide films (CAZO films) using RF magnetron co-sputtering. The CAZO films were deposit...

The present study was conducted to investigate the optical constants of copper (Cu)-doped zinc oxide (ZnO) films annealed at different temperatures. The absorption coefficient of the films increased by changing the annealing temperature. The lattice dielectric constant $$ \varepsilon_{L} $$ , concentration of the free-charge carriers, plasma frequency, Spitzer–Fan model, and the waste heat of electrical energy in the films were analyzed using the refractive index n and extinction coefficient k spectra. The results of the study showed that changing the annealing temperature values significantly influences the refractive index and extinction coefficients of CZO films. The increase in the electrical susceptibility $$ \chi_{c} $$ in annealed films can be due to the increased concentration of free-charge carriers in these films. The maximum electrical energy loss (tan δ) in the films as a function of photon energy occurred at 400 °C. The as-deposited films showed minimum volume and surface energy loss functions in their range of optical band gaps. The variations in the phase and group velocity of the films with post-annealing temperature were consistent with the variations in the reduction of the density of free-charge carriers for these films. Films annealed at 600 °C had the maximum root mean square roughness of about 5.62 nm. Films annealed at 400 °C had the maximum extinction coefficients k such that they increased for all ranges of wavelength. $$ \chi_{c} $$ had the maximum values in the films annealed at 600 °C, for all ranges of wavelength, and they increased by increasing the wavelength. The increase in $$ \chi_{c} $$ of the films annealed at 600 °C can be attributed to the increase in the density of free-charge carriers in these films.

This work describes an analysis of titanium dioxide (TiO2 ) thin films prepared on silicon substrates by direct current (DC) planar magnetron sputtering system in O2 /Ar atmosphere in correlation with three-dimensional (3D) surface characterization using atomic force microscopy (AFM). The samples were grown at temperatures 200, 300, and 400°C on silicon substrate using the same deposition time (30 min) and were distributed into four groups: Group I (as-deposited samples), Group II (samples annealed at 200°C), Group III (samples annealed at 300°C), and Group IV (samples annealed at 400°C). AFM images with a size of 0.95 μm × 0.95 μm were recorded with a scanning resolution of 256 × 256 pixels. Stereometric analysis was carried out on the basis of AFM data, and the surface topography was described according to ISO 25178-2:2012 and American Society of Mechanical Engineers (ASME) B46.1-2009 standards. The maximum and minimum root mean square roughnesses were observed in surfaces of Group II (Sq = 7.96 ± 0.1 nm) and Group IV (Sq = 3.87 ± 0.1 nm), respectively.

In this work, the stereometric 3-D surface topography as well as the optical properties of the Al doped ZnO (AZO), and Al/Cu co-doped ZnO (CAZO) thin films were investigated. These films were deposited with different thicknesses of 50 and 150 nm. The effect of dopants (Al, Cu) and sputtering parameters on the microstructures, crystalline structures, and fractal features were probed by Atomic Force Microscopy (AFM), X-ray diffraction, and Rutherford back scattering. AFM analysis of 3-D surface texture provided a deeper insight into their characteristics and implementation in graphical models and computer simulation. Studying surface roughness of samples at nanometer scale revealed a fractal structure which confirmed the relationship between the value of the fractal dimension and surface roughness parameters. Moreover, the optical properties of AZO and CAZO thin films and the relationship between their optical band gaps and their varied thicknesses were evaluated by Ultraviolet–visible spectrophotometry.

The main goal of the present work is to explore the three dimensional (3-D) atomic force microscopy (AFM) images of human teeth and investigating their micromorphology. For this purpose, 10 fresh and permanent canine teeth were selected from a group of 40-year-old men who were candidate for the experimental processes. Afterward, they were all applied for studying the morphology of their hard tissues. The tapping mode of AFM was used to characterize the surface micromorphology on the square areas of 1 μm × 1 μm (512 × 512 pts). AFM results and surface stereometric analysis indicate the relationships between the micromorphology of the surface and the structural properties of these tissues across the length scales. As can be seen, the surface of cementum has the most irregular topography (D = 2.87 ± 0.01) while the most regular topography (D = 2.43 ± 0.01) is found in dentin. Furthermore, the more and less regularity of the surface have been found in inner enamel (Sq = 26.26 nm) and dentin (Sq = 41.28 nm), respectively. Stereometric and fractal analyses give valuable information about human canine teeth via 3-D micromorphology.

In this study, the average diameter of the grown CNTs on Ni-Cu NPs @ a-C:H substrates were increased by increasing of Cu content. The obtained results indicated that by increase of Cu content, all films exhibited high-absorption spectra; therefore, we were facing an increase in the energy gap of films. The values of dT/dλ and dR/dλ measurements for grown CNTs with 75% Cu shown that maximum values of optical band gap correspond to with values of 2.48 eV and 2.90 eV, respectively. It can be seen that with increase of average diameter of the grown CNTs, the values of Urbach energy of films were increased. The RBS and EDAX measurements were confirmed presence of Ni and Cu atoms into films. The films deposited with 75% Cu were more smooth. Films deposited with 75% Cu have more disordered. Films deposited with 75% Cu atoms have maximum values of the oscillator strength f and the dispersion energy Ed about of 0.108 eV2 and 0.0543 eV, respectively.

In this paper, Ni-Cu NPs @ a-C:H thin films with different content of cooper by co-deposition of RF-sputtering and RF-plasma enhanced chemical vapor deposition (RF-PECVD) were prepared from acetylene gas and Ni and Cu targets. The prepared samples as catalysts for growing multi-wall carbon nanotubes (MWCNTs) were used from liquid petroleum gas (LPG) by thermal chemical vapor deposition (TCVD) at 825 °C. The films deposited with 5% Cu have minimum value the average diameter of CNTs and were about 100 nm. The fractal dimensions and structural characteristics as well as optical density of Ni-Cu NPs thin films have been investigated. AFM images can estimate the lateral size of the nanoparticles on the films surface. These values for Ni NPs without Cu NPs @ a-C:H thin film and with Cu NPs thin film contenting 5%, 40%, 75% Cu are obtained about 7.2, 5.34, 6.04 and 11.16 nm respectively. The optical density (Dopt) of thin films was obtained from the relation Dopt = \alpha t. Films deposited with 75% Cu have maximum value of optical density specially in high energy. The spectral density power of all layers reflects the reverse flow changes,, especially in the high spatial frequency region, indicating the presence of fractal components in prominent topographies. Films deposited with 75% Cu have minimum value of fractal dimension. The diagram of the Bearing Area proportion the height shows the percentage of cavities and single-layers. It can be seen that the single-layer content of all films were about 95%.

The purpose of this in-vitro study is to evaluate and compare the effects of different laser irradiation routines to the surface morphology of zirconia-based ceramics. Sample prepared by a copy milling technique were irradiated using Nd-YAG, Er-YAG, and CO2 infrared lasers. Surface topography of the samples was studied by means of AFM and SEM methods, and changes in their spatial characteristics were analyzed comparing statistical and fractal parameters. Depending on the absorption of incident energy, CO2 laser was found to exert dominant influence on the surface geometry concerning changes in the surface texture, roughness and fractality of the specimens.

In this work, aluminum-doped zinc oxide (AZO) films were annealed under argon flux at different temperatures and cooled down slowly to room temperature. Afterward, optical properties of samples were studied and their optical band gap were estimated by different methods such as dR/dλ (3.33–3.83 eV), dT/dλ (3.8–4.1 eV), optical conductivity (3.7–4.53 eV), dielectric relaxation time (3.65–3.87 eV), d(αhν)/dhν (3.44–3.95 eV), Tauc power law (3.4–4 eV), and the single oscillator model (2.67–3.37 eV). Increasing annealing temperature caused a redshift in the maximum of the dielectric relaxation time (τ) peaks. The dispersion parameters were studied through single oscillator model. The oscillator strength (f) and the dispersion energy (Ed) of films were decreased by increasing annealing temperature so that the films annealed at 600 ∘C had minimum Urbach’ s energy (Eu) of 0.05 eV with minimum disordered. Due to high Al content, asdeposited films had maximum dielectric constant at higher wavelength (e∞)

In this work, the electric properties of carbon films embedded by nickel nanoparticles deposited at different deposition times 50-600 sec were investigated. It can be seen that the deposition time affects on nanoparticle sizes and thicknesses of films. A detailed analysis in terms of phonon-assisted small polaron hopping model is used to correlate electrical transport properties of films in temperature range 150-300 K. With increasing deposition time from 50 to 180 sec the polaron radius (rp) decrease and then from 180 to 600 sec it increased. The polaron radius (rp) of films deposited at 180 sec has minimum value of 8.14 × 10−8cm. The polaron hopping energy (WH) of films deposited at 180 sec has minimum value 0.028 eV. With increasing deposition time from 50 to 180 sec the density of states N (EF) at the Fermi level increase and then from 180 to 600 sec it decreased. The density of states N (EF) at the Fermi level of films deposited at 180 sec has maximum value of 6.09 × 1020 eV−1cm−3.

In this paper, carbon films embedded by Ni nanoparticles were deposited on glass substrates. Films using four mosaic targets made of carbon and nickel with Ni surface areas 1.78, 3.21, 3.92 and 4.64% are made. With increasing Ni content in these films a nonmetal–metal transition especially above room temperature region is observed. This transition is explainable by electrical measurements in temperature range 15–500 K. With increasing Ni surface areas from 1.87 to 4.64%, Ni content of films increases from59.68 to 92.89%. The electrical conductivity of dielectric films was explained by tunneling effect. Activation tunneling energy that was obtained from temperature dependence of electrical resistivity correlates both with G and D peaks of Raman spectra and depend on Ni content of films. With increasing Ni surface areas from1.78 to 3.92% due to increasing graphen like carbon, a nonmetal–metal and from 3.92 to 4.64% due to increasing amorphous carbon interconnections of Ni nanoparticles, a peculiar effect of metallic to nonmetallic state occurs. The RMS roughness of films in 3.92% has minimum value about 0.54 nm.

In this work, the fractal dimensions and electric properties of carbon films embedded by nickel nanoparticles annealed at different temperature 300, 500 and 800 °C were investigated. A detailed analysis in terms of small polaron hoping (SPH) parameters is used to correlate electrical transport properties with annealing temperature in the range 150–300 K. It can be seen that with increasing annealing temperature up to 500 °C the polaron radius (rp) decrease and has a minimum value 4.58 × 10−8 cm then from 500 °C to 800 °C it increased to 6.13 × 10−8 cm. The polaron hopping energy (WH) at 500 °C has minimum value 0.017 eV while the density of states N(EF) at the Fermi level has maximum value 5.43 × 1021 eV−1 cm−3. It can be seen that polaron hopping energy, density of state at Fermi energy and carrier mobility of films correlate with fractal dimensions of films which obtained from the power spectral densities (PSDs) analyses. It can be seen that there are a fluctuation in the polaron mass (mp) and at 500 °C which correspond to maximum value of fractal dimension, has minimum value. With increasing fractal dimensions, carrier mobility of films decreases and have minimum value 1.2 × 10−10 s−1 V−1 cm2.

Un-doped and Cu-doped ZnO (CZO) thin films were prepared by radio-frequency (RF) sputtering. The effects of Cu doping and annealing treatments on the microstructure, fractal features and photoluminescence of these thin films were investigated by different characterization techniques including X-ray diffraction, X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), photoluminescence (PL) and Rutherford back scattering. The results indicated that the Cu-doping enhanced the c-axis preferential growth of the ZnO films, however introduced crystal defects and micro tensions in the crystal lattice reducing the crystal size and the lattice parameter c. The XPS studies revealed that the states of Cu in the doped films were Cu 1+ and Cu 2+ , and the PL characterizations showed that the incorporation of Cu in the crystalline structure of the ZnO thin films produced a green emission at 530 nm. The annealing treatments increased the crystal size in the [001] direction and reduced the lattice parameter c due to the accommodation of the Cu atoms in equilibrium positions. Also, these treatments increased the intensity of the PL peaks. All samples displayed a micromorphology that was successfully described as a fractal structure that can be decomposed into local motifs whose essential features varied with the Cu-doping and/or annealing temperature in agreement with their mentioned influence on the crystallization process of the samples.

In this paper, the films were prepared by radio frequency magnetron co-sputtering technique. The effect of different mosaic targets made of nickel strips and graphite pure on the dielectric relaxation time, the carriers hopping rate, the fractal dimensions and the optical loss of films were studied. The values of the optical band gap of films using the cross-point between the tangent of the plot of lower and higher values of the photon energy were calculated. The films deposited at 4.64% have maximum hopping rate of about 8.6 × 1012 S−1. It can be seen that the films deposited at 3.92% have minimum value of fractal dimension of 2.27. With increasing Ni content of films a nonmetal–metal transition is observed which it is explainable by the power law of percolation theory. Critical metal content and the critical exponent of films were 87.25% and 1, respectively. With increasing Ni content, the carriers effective mass of films decreased and average lattice separation values of films increased. Films deposited at 3.92% have minimum value of Debye frequency νD of about 1.09 × 1012 Hz. The value of energy loss by free charge carriers when traversing the bulk and surface of films at 3.92% has maximum value and it has an increasing function behavior with energy.

This work describes an analysis of titanium dioxide (TiO

In this paper, optical constants, surface topology, and fractal dimensions of zinc oxide films under different post-annealing temperatures from 400 °C to 600 °C especially were investigated near optical band gap of films so that the maximum value of fractal dimension belongs to film annealed at 500 °C with the value of 2.07. In addition, the relaxation time of dielectric were estimated using their high-frequency dielectric constant while optical band gap were calculated through the cross-point between the tangent of lower and higher values of the photon energy in the plot of relaxation time-energy. The high-frequency dielectric constant has the maximum value of 21 for film annealed at 400 °C. It can be seen that the free carriers electric susceptibility of films near optical band gap were increased with temperature. Moreover, the film annealed at 400 °C has high dissipation factor.

This work analyses the three-dimensional (3-D) surface texture of carbon-nickel (C-Ni) films grown by radio frequency (RF) magnetron co-sputtering on glass substrates. The C-Ni thin films were deposited under different deposition times, from 50 to 600 s, at room temperature. Atomic force microscopy was employed to characterize the 3-D surface texture data in connection with the statistical, and fractal analyses. It has been found that up to 180 s the sputtering occurs in more metal content mode and in greater than 180 s it occurs in more non-metal content mode. This behavior demonstrated a strong link between the structural and morphological properties of C-Ni composite films and facilitates a deeper understanding of structure/property relationships and surface defects in prepared samples. Furthermore, these findings can be applied to research on the mechanisms to prepare and control high-quality C-Ni films.

This paper analyses the three-dimensional (3-D) surface texture of Cu/Co thin films deposited by DC-Magnetron sputtering method on the silicon substrates. The prepared Cu/Co nanoparticles were used as research materials. Three groups of samples were deposited on silicon substrates in the argon atmosphere and gradually cooled down to room temperature. The crystalline structures and elemental compositions were analyzed by X-ray diffraction (XRD) spectrum with conventional Bragg-Brentano geometry. X-ray diffraction profile indicates that Co and Cu interpenetrating crystalline structures are formed in these films. The sample surface images were recorded using atomic force microscopy (AFM) and analyzed by means of the fractal geometry. Statistical, fractal and functional surface properties of prepared samples were computed to describe major characteristics of the spatial surface texture of Cu/Co nanoparticles. Presented deposition method is a versatile, costeffective, and simple method to synthesize nano- and microstructures of Cu/Co thin films. This type of 3-D morphology allows to understand the structure/property relationships and to investigate defect-related properties of Cu/Co nanoparticles. Presented results confirm the possibility of preparing high-quality Cu/Co nanoparticles via DC-Magnetron sputtering method on silicon substrates.

In this work, carbon-nickel films were grown during four deposition times (50 s, 90 s, 180 s and 600 s) at room temperature on glass substrates by radio frequency magnetron sputtering. The optical absorption spectra of the films were investigated with a special emphasis on the surface plasmon resonance (SPR) of Ni nanoparticles. The optical absorption peaks caused by the surface plasmon resonance of Ni nanoparticles were observed in the wavelength range of 300 nm to 330 nm. It has been shown that the surface plasmon resonance peaks exhibit a red shift and a blue shift depending on the deposition time. The red and blue shifts of the surface plasmon resonance in the absorption spectra of the films were observed with the increase and decrease of Ni nanoparticle size, respectively. The Ni nanoparticle size, dielectric function of carbon matrix εm and plasma frequency of free electrons ωp for the films deposited at deposition time of 180 s have maximum values of 80 nm, 0.401 and 7.25 × 1015 s–1, respectively. These observations are in a good agreement with the electrical resistivity measurements and Maxwell-Garnett (M-G) effective medium theory (EMT).

This paper analyses the three-dimensional (3-D) surface texture of growing diamond nanocrystals on Au thin films as catalyst on p-type Si substrate using hot filament chemical vapour deposition (HFCVD). Rutherford backscattering spectrometry (RBS), atomic force microscopy (AFM), Raman, X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were applied also to characterize the 3-D surface texture data in connection with the statistical, and fractal analyses. This type of 3-D morphology allows a deeper understanding of structure/property relationships and surface defects in prepared samples. Our results indicate a promising way for preparing high-quality diamond nanocrystals on Au thin films as catalyst on p-type Si substrate via HFCVD method.

In this work, the optical properties of carbon–nickel films deposited at different deposition times from 50 to 600 sec were investigated. The obtained data of the refractive index n can be analyzed to obtain the high–frequency dielectric constant which describes free carriers and the lattice vibration modes of dispersion. The lattice dielectric constant e L and the plasma frequency ω p at 180 sec have maximum values 10.68 and 79.92x106 Hz, respectively. The free carrier electric susceptibility measurements in the wavelength range (300 – 1000 nm) are discussed according to the Spitzer–Fan model. It is shown that the electric susceptibility at 180 sec has a maximum value and with increasing wavelength it increases. The energy loss by the free charge carriers when traversing the bulk of the films at 180 sec has a maximum value and with increasing wavelength it decreases. The field emission scanning electronic microscopy (FESEM) images were used for estimation of particle size.

In this work, the electrical properties of carbon–nickel composite films deposited at different time (50–600 s) were investigated. The films were grown by radio frequency magnetron sputtering on glass substrates at room temperature. The electrical conductivity of the films was investigated in the temperature range of 15–500 K. The conductivity data in the temperature range of 400–500 K show the extended state conduction mechanism, while the multiphonon hopping (MPH) conduction is found to dominate the electrical transport in the temperature range of 150–300 K. The films deposited at 180 s have the maximum conductivity. The conductivity at T

In this paper, Ni-Cu NPs @ a-C:H films with different Cu content, by co-deposition of RF-sputtering and RF-plasma enhanced chemical vapor deposition (RF-PECVD) were prepared using acetylene gas and Ni and Cu targets. We studied optical constants of MWCNTs synthesized, with constant Ni content and different percentages of 5, 40 and 75 % from Cu atoms. With increase of Cu content, the average diameter of MWCNTs were increased however the RMS roughness of films were decreased. It is found that the absorption coefficients of films deposited with 5% Cu have maximum value. Also it can be seen that the minimum values of the optical band gaps of films happen in films deposited with 5% Cu. With increase of Cu content, the values of energy loss by the free charge carriers were increased however the plasma frequency ωp and free charge carriers concentration N/m* of films were decreased. The free carriers electric susceptibility χ c at in films deposited with 75 % Cu has maximum value. The values of the ratio of free charge carriers concentration to effective mass, N/m*, in films deposited with 5% Cu has maximum value about of 423.731048 m−3 kg−1.

The aim of this work is to investigate the optical constants of aluminum doped zinc oxide films annealed at different temperatures. With increasing temperature, due to decreasing unfilled inter-granular volume per unit thickness, the optical transmittance spectra of films were increased. The films have a normal dispersion in the spectral range 400

In this work, the optical absorption spectra of carbon–nickel films annealed at different temperatures (300–1000 °C) with a special emphasis on the surface plasmon resonance (SPR) were investigated. The films were grown on quartz substrates by radio-frequency (RF) magnetron co-sputtering at room temperature with a deposition time of 600 s. The optical absorption peaks due to the SPR of Ni particle are observed in the wavelength range of 300–330 nm. With annealing temperature increasing up to 500 °C due to the increase in Ni particle size, the intensity of the SPR peaks increases, but weakens with annealing temperature increasing over 500 °C. The Ni nanoparticle size, the dielectric function of carbon matrix (e m) and the plasma frequency of the free electrons (ω p) at 500 °C have the maximum values of 21.63 nm, 0.471 and 5.26 × 1015 s−1, respectively. The absorption peak shows a redshift trend up to 500 °C and then turn to blueshift with annealing temperature increasing over 500 °C. These observations are in a good agreement with the electrical measurements in temperature range of 15–520 K and the Maxwell–Garnett (M–G) effective medium theory (EMT).

In this work, the magnetic properties and the electrical conductivity of carbon–nickel composite films deposited at different deposition times 50–600 s were investigated. The films were grown by radio frequency magnetron co-sputtering on glass substrates at room temperature. The nickel concentration in the films are effected by changing of the deposition rate and measured by energy dispersive X-ray studies. Values of coercive field were measured under both increasing and decreasing applied magnetic field. It is shown that the coercive field strongly dependent on both the nickel concentration and nickel nanoparticle size and at 180 s films has maximum value 68.04 (Oe). The difference in the coercive fields increased for films deposited from 50 to 180 s and then decreased for films deposited at 600 s. The ID/IG ratio of Raman spectra would indicate the presence of higher sp2 bonded carbon in the films deposited at 180 s. For entire temperature range (15–500 K), the electrical conductivity of films deposited up to 180 s increases and then from 180 to 600 s it decreases. These observations are in a good agreement with the field emission scanning electronic microscopy (FESEM) images.

In this paper, the optical properties of carbon films embedded by Ni nanoparticles under four deposition processing using mosaic targets made of graphite and nickel with Ni surface areas from 1.78 to 4.64% with a special emphasis on the absorption edge were investigated. Resulting films with Ni surface areas 1.78, 3.21, 3.92 and 4.64% have approximately Ni atomic ratio of about 59.7, 86.5, 90 and 92.9 wt%, respectively. The optical reflectance and transmittance spectra in the wavelength range 300–2500 nm were used to compute the absorption coefficient. The optical dispersion parameters were calculated according to Wemple and Didomenico single oscillator model (WDD). The variation of complex optical conductivity σ with energy of films exhibit values for optical gaps from about 0.8 to 4 eV which correspod to the fundamental indirect and direct gap which are about 0.3 to 3.7 eV. It can be seen that at Ni surface areas 3.92% the films have minimum indirect optical band gap about 0.2 eV. Due to high Ni content of films at 4.64%, they have maximum disordered. It can be seen that these optical properties were in consistent with room temperature electrical resistivity of films.

In this research, we investigated carbon–nickel composite films prepared by RF-magnetron co-sputtering on quartz substrates using a multi-component target (10 cm in diameter) consisting of pure graphite (99.99%) and strips of pure nickel (approx. 2 cm2 in size) attached to the graphite race track, that corresponds to around 2.5% in area. The substrates were ultrasonically cleaned in acetone bath for 20 min and dried in hot air flow prior to deposition process. The films were grown at room temperature in a deposition chamber evacuated to a base pressure 1 × 10−3 N/m2 and then the constant Argon working pressure of 4 N/m2 was settled and maintained by throttle valve. Deposition was done in constant RF power regime 400 W. The films were deposited for 600 s and then annealed for 2 h in a furnace at the temperature: 300, 500, 800 and 1000 °C under ambient atmospheric pressure.

The electronic and the linear optical properties of BeO nanosheet and wurtzite structure are investigated by using the full potential linear augmented plane wave plus local orbital (FPLAPW+ lo) in the frame work of the density functional theory (DFT). The dielectric tensor is derived within the random phase approximation (RPA). Specifically, dielectric function, absorption coefficient, optical conductivity, extinction index, loss function, reflectivity and the refraction index of the BeO nanosheet are calculated for both parallel and perpendicular electric field polarizations. The results show that the optical conductivity in E‖x starts with a gap about 5.89 eV confirms that BeO nanosheet has semiconductor property also the optical spectra are anisotropic along these two polarizations. The static refractive index of nanosheet is smaller than wurtzite structure.

In this work, the optical properties of carbon–nickel films deposited at different deposition times from 50 to 600 sec were investigated. Reflectance measurements in wavelength range 300–1000 nm were used to compute the refractive index and optical dispersion parameters according to Wemple and DiDomenico single oscillator model (WDD). Dispersion curves of the refractive index of films show anomalous dispersion in absorption region and normal dispersion in transparent region. It is shown that dissipative rate of the electromagnetic wave at 180 sec has a maximum value. It is also shown that at 180 sec films become more disordered.

In this paper, the electrical conductivity of carbon films embedded by nickel nanoparticles at different deposition times 50, 90, 180 and 600 s over a temperature range from 50 to 500 K was studied. The conductivity data in the temperature range \(T > 300\) K shows the extended state conduction mechanism. The tunneling through a thermally vibrating barrier in the temperature range 50-150 K is described by the Berthelot-type conduction mechanism. It can be seen that the films deposited at 180 s have maximum conductivity and the Berthelot temperature is about 53.5 K. Due to the vibrations of Ni ions in the tetrahedral, sites the extents of the carrier wave function are lower than in the octahedral complexes sites which have maximum values of about \(2.16 \times 10^{-7}\) cm and \(1.85 \times 10^{-7}\) cm in the octahedral-metal stretching vibrations and intrinsic stretching vibrations of the metal ions at the tetrahedral site, respectively. On the other hand, the average distance between the sites in both vibrations at 180 s deposition modes have minimum values of \(2.02 \times 10^{-7}\) cm and \(1.72 \times 10^{-7}\) cm.

This work analyses the three-dimensional (3-D) surface texture of carbon-nickel (C-Ni) films grown by radio frequency (RF) magnetron co-sputtering on glass substrates. The C-Ni thin films were deposited under different deposition times, from 50 to 600 s, at room temperature. Atomic force microscopy was employed to characterize the 3-D surface texture data in connection with the statistical, and fractal analyses. It has been found that up to 180 s the sputtering occurs in more metal content mode and in greater than 180 s it occurs in more non-metal content mode. This behavior demonstrated a strong link between the structural and morphological properties of C-Ni composite films and facilitates a deeper understanding of structure/property relationships and surface defects in prepared samples. Furthermore, these findings can be applied to research on the mechanisms to prepare and control high-quality C-Ni films.

In this paper, the optical properties of carbon-nickel films annealed at different temperatures 300, 500, 800 and 1000 ° C, with a special emphasis on the absorption edge, were investigated. The optical transmittance spectra in the wavelength range 300-1000nm were used to compute the absorption coefficient. The optical dispersion parameters were calculated according to Wemple and DiDomenico (WDD) single-oscillator model. Photoluminescence (PL) measurements of carbon-nickel films exhibit two main peaks at about 2.5 and 3.3eV which correspond to the fundamental indirect and direct gap, respectively. The field emission scanning electron microscopy (FESEM) showed that the absorption edge in the films was controlled by the nanoparticle size. The films annealed at 500 ° C have minimum indirect optical band gap and maximum disorder.

The densification and the fractal dimensions of carbon–nickel films annealed at different temperatures 300, 500, 800, and 1000°C with emphasis on porosity evaluation are investigated. For this purpose, the refractive index of films is determined from transmittance spectra. Three different regimes are identified, T 800°C. The Rutherford backscattering spectra show that with increasing the annealing temperature, the concentration of nickel atoms into films decreases. It is shown that the effect of annealing temperatures for increasing films densification at T 800°C is greater than the effect of nickel concentrations. It is observed that the effect of decreasing nickel atoms into films at 500°C < T < 800°C strongly causes improving porosity and decreasing densification. The fractal dimensions of carbon–nickel films annealed from 300 to 500°C are increased, while from 500 to 1000°C these characteristics are decreased. It can be seen that at 800°C, films have maximum values of porosity and roughness.

In this work, the microstructure and magnetic properties of carbon–nickel (C–Ni) composite films annealed at different temperatures (300–1000[Formula: see text]C) were investigated. The films were grown by radio frequency magnetron sputtering on quartz substrates at room temperature. The nickel concentration in the films are affected by changing of the value of evaporation nickel atoms and measured by Rutherford backscattering spectroscopy (RBS). Values of coercive field were measured under both increasing and decreasing applied magnetic field. It is shown that the coercive field of films strongly dependent on the annealing temperature and at 500[Formula: see text]C films has maximum value of 93.67[Formula: see text]Oe. The difference in the coercive fields increased for films annealed from 300 to 500[Formula: see text]C and then decreased from 500 to 1000[Formula: see text]C. The ID/IG ratio of Raman spectra would indicate the presence of higher sp2 bonded carbon in the films annealed at 800[Formula: see text]C.