Papers by Keyword: Spray Pyrolysis

Abstract: The research on transparent heater (Thf) films rapidly increases due to their unique photoelectric properties, leading to new generation of optoelectronic device. Here, we report a simple method to fabricate transparent heater based on Al-doped SnO₂ (ASO) thin films. ASO films with 5 wt% Al as dopant were synthesized with various deposition times, namely, 5, 10 and 15 minutes using ultrasonic spray pyrolysis method. The correlation of deposition time on their structural characteristic, optical, electrical and thermal properties has been investigated. X-ray diffraction studies found that all samples exhibit tetragonal structure with preferred orientation along (110) plane. Meanwhile, the UV-Vis transmittance indicated that the sample having good optical transparency in visible light spectrum with the average transmittance up to 89.7%. The sheet resistance of ASO thin films was found to decrease as the deposition time increases to 10 minutes. Furthermore, Al-doped SnO₂ based transparent heater prepared with 10 minutes deposition time presents the excellent thermal temperature up to 76.3 °C at the applied voltage of 20 volt. The above findings reveal that Al-doped SnO₂ can be used as an alternative compound to substitute higher cost indium tin oxide as transparent heater. Keywords: aluminium, composite, spray pyrolysis, SnO₂, transparent heater

Abstract: Heterostructure thin films of indium and zinc oxides (IZO) were prepared by spray pyrolysis from an aqueous solution of the precursors at different substrate temperatures (T_S). The polycrystalline structure of bixbyite appeared at a low temperature. The crystallinity was enhanced with the emergence of the zinc oxide phase. By increasing the T_S to 623 K, the crystallite size was increased. SEM images reveal that the deposited sample at 523 K is composed of irregularly shaped nanoparticles with a lack of links. Increasing the T_S to 573 K increases the average particle diameters, and the particles appeared as polyhedrons well connected with cavities between them, which candidates for gas sensing applications. Increasing T_S to 623 K resulted in the particles merging. NO₂ gas sensor results confirmed the enhancement of IZO sensitivity performance at 573 K. Keywords: Gas sensor, thin film metal oxide, spray pyrolysis, In₂O₃– ZnO

Abstract: In this paper, the influence of the precursors of nickel oxide (NiO) on the properties of ZnO/NiO nanocomposites thin films, grown by spray pyrolysis method, has been investigated. The nickel sulfate, nickel chloride and nickel nitrate have been used as precursors of NiO, each precursor has been mixed with Zinc oxide (ZnO)’ precursor to elaborate ZnO/NiO nanocomposites thin films with the method mentioned above. The aim of this paper is to confirm the similitude of precursors in the nanocomposites. For this reason, and to reveal this goal, some techniques were used as the structural analysis by X-ray diffraction (XRD) which a high intensity has been detected corresponds to the ZnO / NiO films with nickel chloride precursor, UV-Visible characterization depicts the presence of a maximum adsorption band appears in the ultraviolet range, the morphological characterization with Atomic Force Microscopy (AFM) reveals the roughness and the different grain size of particles, the big one of the latter agree, also, with to nickel chloride precursor used. The values of optical band gaps E_g are globally equal with high value noticeable agree with films that prepared with nickel chloride and zinc chloride precursors. The results obtained confirm the aim and a good agreement with the latter were found.

Abstract: In this research, SnO₂ nanostructure thin films were fabricated by spray pyrolysis method, using concentration of tin (Sn) salt solution deposited on a glass substrate at temperature of 450 °C. The tin solution was prepared by solves 2.2563gm of SnCl₂.2H₂O (molecular weight 219.4954 g/mole) in 100 ml of ethanol, then add 60 drops of pure hydrochloric acid ( HCl) using drop by drop technique. Different concentrations of antimony oxide (1%, 2%, 3%, 4%) hve been used to depose the thin films. The structure has been examined by X-ray diffraction technique, which shown that all films are polycrystalline with tetragonal rutile crystalline structure with preferential orientation in the (200) direction and, grain size decreases with increasing doping concentration. Optical measurements shown that the films are transparently in the visible region, with an average transmittance more then 80% and, sharp absorption edge nearly at 350 nm, the nature of the optical transition were direct allowed with band gap varies between (2.97 - 3.75 eV) which is directly proportional to doping concentration. The results also show that the doping has led to improved the response time of the sensing. Two kinds of gases NO₂ and NH₃ have been used to test the sensing performance, at different operating temperatures (R.T, 100, 200, 250, 300 and 350) oC , and bias voltage (3 Volt). For NO₂ gas the highest sensitivity was 77%, the shortest response time 2.9 s and the recovery time 19 s, while for NH₃ gas sensitivity was 11.5%, the response time 4.1 s and the shortest recovery time 20s,

Abstract: By using the spray pyrolysis technique, un-doped and Fluorine highly doped iron oxide Fe2O3 thin films were deposited on a glass substrate at a temperature of 380 oC and at different dopant concentrations (10, 15, and 20) %. The crystal structure and optical characterization of the deposited thin film were performed by x-ray diffraction and UV-Vis spectrophotometer. The XRD results revealed that the presence of a very wide peak in-between (15-35) o angles, this gives evidence that un-doped and F-doped Fe2O3 thin films have very low crystallinity and amorphous structures. The optical absorbance edge was shifted towards short wavelengths (blue shift) and the absorbance was reduced with the increase of Fluorine dopant content. The optical constants such as absorption, extinction coefficients, and the optical conductivity of the deposition films were investigated as a function of dopant content. The optical energy band gap of un-doped and Fe2O3:F thin films was found to be increased when increasing of the Fluorine content and exhibited a direct allowed energy gap (Eg) from (2.55 to 2.7) eV which can related to the Burstein-Moss effect.

Abstract: The based semiconductor-metal oxide gas 3D-detector of cadmium oxide has been fabricated from cadmium chloride salt upon a glass substrate via the technique of spray pyrolysis with a thickness around (0.5 ± 0.01 μm) utilizing precursors in form of water soluble at a flat glass substrate and a tube hollow design. Three different dimensions were used at temperature 450oC±5, in 0.1 and 0.2 M concentration, and their gas sensing characteristics toward the (CO) and (NO) gases at various concentrations (50, 100, and 500 ppmv) in the air were studied at the room temperature which are related to oil industry. Different inspection distances (0, 1 and 5 m) were carried out. Furthermore, structural and morphology properties were inspected via X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The results manifested that the composition of the formative oxide CdO is related to the tested oxidation gases sensitivity. And, the installation of hollow design is best from flat to capture the gas molecules.

Abstract: Zinc oxide codoped with Fluorine and Cobalt thin films (FCZO) were successfully synthesized on heated glass substrate at 380 °C by spray pyrolysis technique. The influence of doping and codoping on the structural, optical and electrical properties were investigated. X-ray diffraction results showed that the undoped and FCZO films exhibit the hexagonal wurtzite crystal structure with a preferential orientation along [0 0 2] direction. No secondary phase is observed in FCZO films. The optical transmittance of Co doped ZnO thin films reduces up to 80 % as compared to undoped ZnO thin film in the visible region. We have observed three absorption bands at 568, 608 and 659 nm which can be attributed to the d-d transitions of tetrahedrally coordinated Co²⁺ ion in the high spin state. The band gap was found to be increasing in the range of 3.26-3.39 eV with Co doping whereas it decreases for higher doping of Co concentration.

Abstract: This article reports on the role of potassium (K) as dopant in Cu₂ZnSn (S,Se)₄, CZTSSe thin film in context of optical properties. Thin film precursor solution is prepared in dimethyl sulfoxide (DMSO) solvent, and doped by K with six different concentrations. The prepared solution are deposited on heated soda lime glass (SLG) substrates using spray pyrolysis technique, followed by selenization process using three-step temperature approach. UV-Visible spectra show high absorption coefficient, α, more than 10⁴cm^-1 and bandgaps in narrow range 0.98eV to 1.10eV. X-ray diffractograms show that all samples exhibit kesterite structure with preferential orientation along (112) orientation. Field Emission Scanning Electron Microscopy was used to determine the morphologies of the K-doped CZTSSe thin films. 1.5 mol % of K has shown better characteristics as an absorber layer among other tested samples.

Abstract: This document describes the technology of manufacturing metal oxide films ZnO, SnO₂, Zn₂SnO₄ from aqueous solutions of the corresponding salts by spray pyrolysis. The modes and conditions of deposition of metal oxide films on hot (420 °C) glass substrates are given. The electrical parameters of the films were measured by the van der Pau method and by the Hall effect, the surface resistance was in the range from 140 to 85⋅10³ Ohm/. The band gap was determined by light absorption spectra and was within 3.2...3.5 eV. For all metal oxides, the n-type conductivity was determined using the thermosonde and the Hall effect.

Abstract: In this study, we report structural, morphological and optical properties of Fe-doped SnO₂ thin layers. Fe doping concentration has evaluated from 0 to 0.6 wt.%. XRD and SEM results revealed a polycrystalline structure for Fe-doped SnO₂ thin layers. The optical transmittance of all thin layers displayed high transparency reach to 80% in the visible region. The optical gap of these layers decreases from 3.87 to 3.58 eV. The grain sizes decrease from 35 to 30 nm. The electrical resistivity of layers increases from 1.2×10^-2 to 6.8×10^-2 Ω.cm.