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Nickel sulfide (NiS) thin film has been deposited on glass substrates by spray-pyrolysis at 325 ± 5 °C. The precursor aqueous solution was synthetized using hexahydrated nickel nitrates and thiourea. The structural, morphological, optical and electrical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy and four probes electrical measurements. The XRD analysis confirmed the hexagonal structure of NiS thin film, which was found to crystalize along [010] direction with an average crystallites size of 10.5 nm. The lattice parameters are a = b = 3.420 Å and c = 5.300 Å in the space group P63/mmc. The optical properties of the films were investigated through the transmittance and the reflectance measurements. The results revealed that the material exhibits a direct optical band gap of 1.03 eV. The elementary composition analysis confirmed the presence of Ni and S with a stoichiometry ratio (Ni/S) of 1.05. The morphology analysis revealed a homogenous crack-free, compact appearance and a granular surface in all scanned areas. The average roughness of the surface was 6.48 nm. On the other hand, the film exhibits a high electrical conductivity ca. 1.10 × 105 S/cm at room temperature. The above results show that the prepared NiS in this study has a good crystallization, dense morphology, good stoichiometric ratio and high conductivity; therefore, it stands as a potential candidate for application in supercapacitors as an electrode material.

The present study reports on the deposition of Nickel sulfide (NiS) thin films on glass substrates by spray-pyrolysis at 300 ± 5 °C with different concentrations of nickel precursor (0.03, 0.05, an...

Pristine and Cobalt (Co)-doped MoO3 nanofilms were synthesized on glass substrates using the spray pyrolysis method. The nanometric pristine MoO3 films were prepared from the 10−2 M.L-1 solution of ammonium molybdate tetrahydrate [(NH4)6Mo7O24,4H2O] in distilled water. Co-doping at 0.5, 0.75 and 1% was achieved by adding cobalt (II) chloride hexahydrate (Cl2CoH12O6) in the pristine solution. The structure and the morphology of the films were investigated by means of X-ray diffraction and atomic force microscopy: two pronounced (020) and (040) peaks corresponding to the orthorhombic structure phase of α-MoO3 were detected. The AFM observations revealed the formation of micro-plates, parallel to the surface plane, with a roughness ranging from 33 nm to 54 nm. Optical properties were investigated through reflectance, transmittance and photoluminescence measurements. The optical band gap, the Urbach energy and the refractive index were deduced from these measurements. The presence of oxygen vacancies was revealed from the interband transitions in the blue and green domains. Co-doped MoO3 nanofilms showed ferromagnetic behavior. The photocatalytic degradation of an aqueous solution of methylene blue (MB) under UV irradiation, in the presence of Co-MoO3 nanomfilms, has been carried out using UV–vis spectrometery: the intensity of the absorption peak recorded at 660 nm decreased with the increase of the UV-illumination time while the color of the initial MB solution was drastically waned.

Quaternary oxides based on strontium, iron, and molybdenum elements such as Sr2FeMoO6 (SFMO) and its analog n = 2 Ruddlesden-Popper (R-P) phase Sr3FeMoO7 were synthesized using chemical spray pyrolysis deposition technique. Optical band gap values, thermal conductivity and thermal diffusivity of both spray-deposited films were investigated. The results confirm that the above properties are considerable factors in forecasting the appropriate perovskite compound for future thermal barrier coating applications.

Pure and Cu-doped NiO films were synthesized via a soft chemical process. They were deposited on glass substrates heated to 400 °C. Different atomic percentage ratios (2, 4, 6, 8, and 10%) of Cu-doping were used. The prepared samples were characterized by several techniques such as X-ray diffraction for crystallographic study, SEM and AFM for microstructural and morphological properties, and UV-Visible spectroscopy for optical and photocatalytical analysis. XRD results of pure and Cu-doped NiO films indicated the formation of NiO polycrystalline phases under a cubic structure with a favored orientation along the (200) plane noticed in all sprayed films. SEM images revealed the formation of NiO nanoparticles of spherical forms whose sizes increase and agglomerate with increasing Cu-doping. At 10% Cu-doping, NiO agglomeration was extended to the whole surface. AFM images showed a textured and rough surface composed of NiO nanoparticles of average size varying from 16 to 10 nm depending on Cu-doping concentration. UV-visible spectroscopy confirmed the transparency of NiO films and their semiconducting character with a band gap ranging from 3.4450 eV to 2.8648 eV. The photocatalytical properties of pure and Cu-NiO films were enhanced by Cu-doping particles as revealed by the degradation of methylene blue (MB) solution subjected to irradiation.

ZnO thin films were synthesized on silicon and glass substrates using the plasma-enhanced chemical vapor deposition (PECVD) technique. Three samples were prepared at substrates temperatures of 200, 300, and 400◦C. The surface chemical composition was analyzed by the use of X-Ray Photoelectron spectroscopy (XPS). Structural and morphological properties were studied by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Optical properties were carried out by UV-visible spectroscopy. XPS spectra showed typical peaks of Zn(2p3/2), Zn(2p1/2), and O(1s) of ZnO with a slight shift attributed to the substrate temperature. XRD analysis revealed hexagonal wurtzite phases with a preferred (002) growth orientation that improved with temperature. Calculation of grain size and dislocation density revealed the crystallization improvement of ZnO when the substrate temperature varied from 200 to 400◦C. SEM images of ZnO films showed textured surfaces composed of grains of spherical shape uniformly distributed. The transmittance yields are reaching 80%, and the values of the band-gap energy indicate that the ZnO films prepared by PECVD present transparent and semiconducting properties.

This paper deals with the results on the structural, electrical, vibrational and optical properties of LaMn1−xNixO3 (0 ≤ x ≤ 0.3) thin films prepared by the spray pyrolysis technique on glass substrates at 460 °C using (LaCl3·7H2O), (MnCl2·4H2O) and (NiCl2·6H2O) as precursors. First, XRD analysis shows an orthorhombic structure of all prepared thin films. Second, room temperature Raman spectra showed broad and intense bands characteristic of LaMnO3 parent compound modes. An important shift to higher frequencies was observed and attributed to disorder induced by Ni composition and Frenkel defects associated to the formation of vacancy and interstitial oxygen sites. The optical measurements show that the optical band gap energy value varies sparsely in terms of Ni content. On the other hand, the electric conductivity measurements were investigated using the impedance spectroscopy technique in the frequency range 5 Hz–10 MHz at various temperatures (410–500 °C). AC conductivity of LaMn1−xNixO3 thin films is found to follow the Jonsher law. The temperature dependence of the AC conductivity is consistent with the correlated barrier-hopping model with activation energy Ea varying in (0.70–1.29) eV domain. Finally, the magnetic hysteresis loops of such films exhibit obvious ferromagnetic behavior with a high dependency with Ni content particularly the coercivity value (Hc) increases with Ni concentration.

We report on the photocatalytical properties of pure and barium-doped nickel oxide nanofilms synthesised on glass substrates using a simple spray pyrolysis method. The nanofilms were prepared from ...

This work highlights some physical properties related to the influence of aluminum, tin and copper incorporation on nanostructured zinc oxide (ZnO:M; M:Al, Sn and Cu) thin films prepared by ultrasonic spray pyrolysis technique (USP) on glass substrate at 350±5 °C. For the as-grown layers, M- to Zn-ratio was fixed at 1.5 %. The effects of metal doping on structural, morphological, optical and electrical properties were investigated. X-ray diffraction pattern revealed that the as-prepared thin films crystallized in hexagonal structure with (0 0 2) preferred orientation. The surface topography of the films was performed by atomic force microscopy. AFM images revealed inhibition of grain growth due to the doping elements incorporation into ZnO matrix, which induced the formation of ZnO nanoparticles. Optical measurements showed a high transparency around 90 % in visible range. Some optical parameters, such as optical band gap, Urbach energy, refractive index, extinction coeffi-cient and dielectric constant were studied in terms of doping element. Particularly, dispersion of refractive index was discussed in terms of both Cauchy and single oscillator model proposed by Wemple and DiDomenico. Cauchy parameters and single oscillator energy E0 as well as dispersion energy Ed were calculated. Finally, electrical properties were investigated by means of electrical conductivity and Hall effect measurements. The measurements confirmed n type conductivity of the prepared thin films and a good agreement between the resistivity values and the oxidation number of doping element. The main aim of this work was the selection of the best candidate for doping ZnO for optoelectronics applications. The comparative study of M doped ZnO (M:Al, Sn and Cu) was performed. High rectifying efficiency of the Al/n-ZnO/p-Si/Al device was achieved and non-ideal behavior was revealed with n > 4.

Lithium-doped zinc oxide thin films (ZnO:Li) at different percentages (0–4%) were deposited on glass substrates at 460 °C using the spray pyrolysis technique. The effect of lithium content on the structural, morphological and optical properties of ZnO:Li thin films was investigated. First, X-ray diffraction study revealed that undoped and Li-doped ZnO thin films crystallize in hexagonal wurtzite structure with a preferred orientation of the crystallites along (002) direction. The scanning electron microscopy (SEM) showed a clear hexagonal-shaped granular onto the surface of such films. Indeed, the averaged grain size, visualized by SEM, varied from 100 nm, for undoped ZnO, to 200 nm for ZnO:Li 4%. Second, the optical analysis by means of the transmittance and the reflectance measurements revealed that in UV–Vis domain, the average transmittance of the ZnO:Li thin films was 75%, while the average reflectance was

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Nanostructured thin films of Nickel oxide NiO were synthesized using spray coating method. The samples were irradiated at different γ-doses by Co-60 radioisotope. The obtained films were studied using X-ray diffraction (XRD), scanning electron microscopy, UV–visible spectrophotometry, Raman spectroscopy, photoluminescence (PL) spectroscopy and FT-IR. The experimental results demonstrated that the irradiation of NiO led to significant changes. XRD and Raman spectroscopy demonstrate that the as-deposited NiO samples show a cubic structure with (111) preferred orientation common at all gamma radiation doses. The optical energy gaps of the samples were found to decrease when increasing the γ ray dose, the Eg value decreases from 3.84 eV for as deposited NiO thin film to 3.60 eV for sample irradiated at 50 kGy. Scanning electron microscope (SEM) image of sprayed NiO films shows the high porosity and the presence of microcavities in surface of films.

In2O3 : Eu thin films were successfully grown by spray pyrolysis. XRD studies showed that the films had In2O3 cubic structure with (004) preferential orientation and best crystal properties at 1.5% Eu doping level. The optical band gap energy decreased with Eu content around 4.1 eV. Urbach energy was of the order of 278 meV, it decreased with Eu content which indicates a decrease in the defects by doping. The dispersion of the refractive index was discussed. Raman spectroscopy showed the band positions corresponding to In2O3 cubic phase with a small shift related to europium incorporation within In2O3 matrix. PL measurements showed a large band which was located at 410 nm and related to the band-to-band transitions and other bands related to impurity levels. Finally, the electric conductivity was investigated depending on the effect of temperature. Activation energy was found to range from 45 to 60 meV for films which were prepared with 1% Eu content.

Hausmannite Mn 3 O 4 thin film have been synthesized using spray pyrolysis method. These films are characterized using X-ray diffraction (XRD), atomic force microscope AFM, UV–vis–NIR spectroscopy and impedance spectroscopy. XRD study confirms the tetragonal structure of the as-deposited films with lattice parameters, a = 5.1822 A and c = 9.4563 A and a grain size of about 56 nm. UV–vis–NIR spectroscopy was further used to estimate optical constants such as extinction coefficient, refractive index, band gap and Urbach energy. Moreover, impedance spectroscopy analysis was employed to estimate electrical and dielectrical properties of the sprayed thin films. The activation energy values deduced from DC conductivity and relaxation frequency were almost the same, revealing that the transport phenomena is thermally activated by hopping between localized states. The AC conductivity is found to be proportional to ω s . The temperature dependence of the AC conductivity and the frequency exponent, s was reasonably well interpreted in terms of the correlated barrier-hopping CBH model. The dielectric properties were sensitive to temperature and frequency. The study of the electrical modulus indicated that the charge carrier was localized. Experimental results concerning optical constants as Urbach energy, dielectric constant, electric modulus and AC and DC conductivity were discussed in terms of the hopping model as suggested by Elliott.