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In this work, the main object of this research is to investigate a new material based on ZnS and NiS nanostructures. NiS and ZnS solutions were sprayed on the heated Low Carbon Steel by a spray pneumatic deposition method. Electrochemical analyses of the prepared samples were investigated. The high corrosion resistance of coated by ZnS sample have a low value of surface roughness. However, the coated sample by ZnS also has good stabilization after corrosion and high compact of the film.

This work examines the grown of Zn1-xCoxO films at different Co concentrations at 420°C by ultrasonic spray deposition. The effect of Co concentration of Zn1-xCoxO films on optical characterization, structure crystallinity and electrical conductivity was studied. Transmission spectra of Zn1-xCoxO films presented three edges in the visible region, it was observed in the range of 541 and 656 nm of wavelengths, which related to the d-d transitions of Co2+ ion with 3d7 high-spin configurations in a tetrahedral crystal field formed by neighboring O2−ions. The gap energy was found increases after doping by Co to maximum value of 3.373 eV at x=0.04. The Urbach energy minimum was 0.083eV, it is obtained for x=0.01. The sprayed Zn1-xCoxO films exhibit a wurtzite structure with preferred orientation in the (002) direction. The maximum crystallite size of Zn1-xCoxO films was 95.61 nm at x=0.06. The maximum electrical conductivity of the Co doped ZnO films was located at x=0.06. [ABSTRACT FROM AUTHOR]

In this work, copper doped nickel oxide as the thin films have been elaborated by a spin coating method, the nickel chloride hexahydrate (0.8M) and copper (II) chloride dehydrate (Cu/Ni = 0, 2.15, 4.3, 8.6 and 12.9 At.%) were used to prepare the Cu doped NiO thin films. The Cu doped NiO thin films were heated at a crystallization temperature of 600 °C with 2 h. The obtained thin films by spin coater method have a film thickness in the order of 400 nm. The prepared Cu doped NiO thin films have a polycrystalline with cubic structure (200) peak was observed. The optical property shows that the prepared thin films have a transmittance of about 70 %. The Cu doped NiO thin films have minimum bandgap energy is 3.85 eV at 12.9 at.%, the thin film deposited at 8.6 at.% has the highest value of Urbach energy is 425 meV. The Cu doped NiO thin films have a high electrical conductivity of 8.6 at% it is 7 (Ω.cm)−1. The prepared Cu doped NiO thin film was suitable for gas sensing applications due to the existing phase and higher electrical conductivity.

In this work, the In2O3 thin films have been fabricated using a spin coating technique; this technique was prepared in our laboratory. The effect of the layer times (3, 5, 7 and 9 times) on optical and structural properties was investigated. In2O3 thin films were fabricated by dissolving 0.2 M of the indium chloride dehydrate InCl3.2H2O in the absolute H2O. The In2O3 thin films were crystallized at a temperature of 600 °C with pending time of 1 hour. The optical property shows that the prepared In2O3 thin films for 3 and 5 times have a transmission of about 85 %. The maximum bandgap energy was 3.69 eV for 5 times and the lowest Urbach energy was 0.47 eV for 9 times. From XDR all fabricated In2O3 thin films having one diffraction crystal plan is (222) peak intensity, this attribution have good crystalline structure with minimum crystallite size of the (222) plan is 59.69 nm. The prepared In2O3 thin films can be used in photovoltaic applications due to the existing phase and higher transmission.

We investigated the structural and optical properties of zinc oxide (ZnO) thin film as the n-type semiconductor. In this work, the sol–gel method used to fabricate ZnO thin film on glass substrate with 0.5 mol/l of zinc acetate dehydrates. The crystals quality of the thin film analyzed by X-ray diffraction and the optical transmittance was carried out by an ultraviolet-visible spectrophotometer. The DRX analyses indicated that ZnO film have polycrystalline nature and hexagonal wurtzite structure with (002) preferential orientation and the measured average crystallite size of ZnO of 207.9 nm. The thin film exhibit average optical transparency about 90 %, in the visible region, found that optical band gap energy was 3.282 eV, the Urbach energy also was calculated from optical transmittance to optimal value is 196.7 meV.

Using a spray pneumatic technique, cobalt (Co) and copper (Cu) co-doped zinc oxide thin films were effectively deposited on a glass substrate. The goal of this work was to create a semiconductor with good optical and electrical properties by co-doping ZnO thin films with Cu and Co. The ZnO thin films obtained from the Co and Cu co-doping exhibit patterns of x-ray diffraction spectra that suggest they are hexagonal ZnO (wurtzite, JCPDS 36-1451). The thin film elaborated with 2 % Co and 7 % Cu has the lowest value of crystallite size (D = 14.67 nm). The transmission spectra demonstrate that all films have good optical transparency in the visible spectrum, with 7 % Cu achieving the highest transmission. Increasing Cu contents raised the band gap energy. The value at the minimum was 3.31 eV. The optical band gap's broadening is a significant characteristic of advanced materials and may be useful in applications involving metal oxide nanostructures for visible light gas sensing. [ABSTRACT FROM AUTHOR]

In this paper, a new mathematical model has been developed to calculate the optical properties of nano materials a function of their size and structure. ZnO has good characterizatics in optical, electrical, and structural crystallisation; We will demonstrate that the direct optical gap energy of ZnO films grown by US and SP spray deposition can be calculated by investigating the correlation between solution molarity, doping levels of doped films and their Urbache energy. A simulation model has been developed to calculate the optical band gap energy of undoped and Bi, Sn and Fe doped ZnO thin films. The measurements by thus proposed models are in agreement with experimental data, with high correlation coefficients in the range 0.94-0.99. The maximum calculated enhancement of the optical gap energy of Sn doped ZnO thin films is always higher than the enhancement attainable with an Fe doped film, where the minimum error was found for Bi and Sn doped ZnO thin films to be 2,345 and 3,072%, respectively. The decrease in the relative errors from undoped to doped films can be explained by the good optical properties which can be observed in the fewer number of defects as well as less disorder.

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, and 0.07 M). The precursor aqueous solutions were synthesized using hexahydrated nickel nitrates and thiourea with a stabilization ratio nickel/sulfur of 1/3. The X-ray diffraction (XRD) study revealed a polycrystalline character with a hexagonal crystal structure. The crystallites size varied from 23.9 to 42.7 nm with an increase in the precursor's concentration. Furthermore, the optical band gap decreases from 1.07 to 0.96 eV. The elementary composition analysis confirmed the presence of Ni and S elements in the samples. Both scanning electron microscopy (SEM) and atomic force microscopy (AFM), revealed a homogenous crack-free and compact appearance in all scanned areas with spherical grains. In addition, the roughness of the films significantly increases with the increase of the precursor's concentration. On the other hand, the film prepared with 0.05 M exhibits a high electrical conductivity and capacitance ca. 1.97 × 103 S/cm and 115 µF/cm2, respectively, at room temperature. The above results showed that the films prepared in this study are very attractive as an electrode material for application in supercapacitors. [ABSTRACT FROM AUTHOR]

In the present research, thin films of zinc oxide (ZnO) are elaborated by solar spay pyrolysis method with using solar energy to heat glass substrate at 450°C in ambient atmosphere without any special conditions. This method was developed in our laboratory using simple tools. The zinc acetate with a molarity of 0.1 M was sprayed with deferent deposition rates (7, 11 and 13 ml). The effect of such depositions on the structural, optical, and electrical properties is examined by using x-ray diffraction (XRD), ultraviolet and visible spectroscopy, and four-point probe method, respectively. The analysis of properties shows that ZnO films are polycrystalline with the preferential orientation (002) and are crystallized in the wurtzite-phase type. The grain size increases to 23 nm, then decreases until it reaches 16 nm. The direct band-gap value decreases from 3.30 to 3.28 eV, when the thickness increases from 126 to 148 nm. As revealed, the conductivity varies with film thickness. [ABSTRACT FROM AUTHOR]

In the present paper, thin NiO films are prepared on glass substrates, using spin-coating method for sol–gel solution with a concentration of 0.7 M. There were the NiO films annealed at different temperatures of 25, 450, 500, 550 and 600°C for 2 hours. XRD spectra indicate that the films exhibit polycrystalline structure, which belongs to the cubic type of NiO. It is obtained that the crystallite sizes are increased to the maximum value of 50.32 nm along (200) plane and obtained at 600°C. The crystallinity of the thin films is improved at a high temperature, for which there are only a few defects. UV–vis spectrophotometric detection of NiO films shows an average transmittance of about 85%. The band-gap energy is increased after annealing from 3.101 to 3.855 eV for unannealed films and annealed ones at 500°C, respectively. At high annealing temperature, the thin NiO films become less disordered with fewer defects, which are related to the Urbach energy that can be obtained by the order of magnitude as 180 meV at 600°C. The transparent thin NiO films become conducting to have a minimum value of the sheet resistance that is revealed at a lower temperature. The best-estimated structure and optical characterization are achieved for the NiO films annealed at 500°C. [ABSTRACT FROM AUTHOR]

On the 01 March, 2020, an outbreak of coronavirus disease 2019 (COVID-19) has resulted in 88 585 confirmed cases. African countries move from COVID-19 readiness to respond as many confirmed cases. The equator differs from the rest of the world in its climate and environment. In this work we conducted a comparative study of cases of coronavirus infection and the number of deaths, this study was investigated in nine countries from Africa with the same climate and which belong to the equator, where the results were compared with the relation to the general population and total area. From the studied results, we found a zero % of the Deaths for Rwanda, Equatorial Guinea and Uganda. The equator countries of Africa have not been affected much by this virus, Climate found in the equator countries helped these countries to obtain a small number of injuries, Air and temperature affected the number of deaths, and the equator countries authorize its climate to help them acquire special immunity. [ABSTRACT FROM AUTHOR]

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