Key Engineering Materials Vols. 675-676

Abstract: SnO₂-ZnO composite films were employed as photocatalytic degradation of organic dye. SnO₂ and ZnO were mixed in polyethylene glycol solution with various weight ratios of SnO₂. The composite paste was screened onto glass substrate with active area of 1 cm² and annealed at 400 °C. The photocatalytic activity of composite films for the degradation of Eosin-Y dye was investigated under UV light irradiation. It was found that the normalized absorbance of dye solution decreased after treatment indicated that dye molecules were reduced. The composite films showed better degradation efficiency than conventional ZnO films due to reduced recombination encourage longer reaction time of electron and hole with surrounded environment. The optimized weight ratio of 30% showed the highest degradation rate constant and the lowest half lift.

Abstract: In this study were to explore the properties of interaction between cellulose and calcium carbonate particle (CaCO₃) which derive from Papia Undulates Shell in procedure of biocomposite synthesis. The structural properties of cellulose powder Papia Undulates Shell and cellulose-calcium carbonate composite film were investigated by using X-ray Diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) and the compositions of cellulose/CaCO₃ biocomposite film were studied by Energy Dispersive X-ray Fluorescence (EDXRF). The experimental results demonstrated the morphology of Papia Undulates Shell were crystalline aragonite phase and the cellulose have structural as amorphous-crystalline but after film forming the composite film between cellulose and Papia Undulates Shell also have amorphous structural. The result of FTIR used to confirmed the formation of bonding between molecular, it indicated that the cellulose/CacO₃ biocomposite film had good biocompatibility due to the biocomposite film have both characteristic feature of CO₃^-2 group (~874 cm^-1 and ~713 cm^-1) and the glucose of cellulose at ~1635, ~1064 and ~946 cm^-1. Another that, the result from EDXRF shown the chemical composition of organic compound of cellulose/CaCO₃ biocomposite film was highest with 99.437 while the Papia Undulates Shell have 0.341 Wt% with corresponding with the ratio of filler material which mixture as 1%. So that, the cellulose/calcium carbonate bicomposite film could be candidate for biocomposite film application.

Abstract: In present study, the structural and trace element were preliminary survey the potentiality to use as filler material for produced the biocomposite films. The first raw material is chitosan and the second raw material is chicken eggshell. Both raw material were investigated the structural and morphological with X-ray Diffraction (XRD) and Scaning Electron Microscope (SEM), respectively. While, Fourier transform infrared spectroscopy (FT-IR) the Energy Dispersive X-ray Fluorescence (EDXRF) were used to investigate functional group and trace element, respectively. The result show that, both material have crystalline structural. The chicken eggshell have calcite structure while the chitosan have amorphos-crystalline structure. The chemical composition in both material compose of P, Ca, Fe similarly but the concentration have been different.

Abstract: Transparent niobium oxide thin films were prepared by dc reactive magnetron sputtering under different oxygen flow rate. The niobium oxide thin films have been deposited on silicon wafer and glass substrate from a 99.99% pure niobium target at room temperature. The films were characterized to obtain the relationship between oxygen flow rate and deposition rate, structural, morphology and optical. The result show that the deposition rate decreased with increasing the oxygen flow rate. However, the transmittance spectrum percentage increases with increasing the oxygen flow rate.

Abstract: The effect of annealing temperature on the electrochromic properties of the tantalum oxide (TaO) thin films deposited on silicon wafer (100) and indium tin oxide (ITO) substrates by dc reactive magnetron sputtering was investigated. The films were annealed at 300, 400 and 500 °C in vacuum for 2 hour. The crystalline structure, morphology, optical properties and electrochromic properties of as-deposited and annealed film were deduced by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), spectroscopic ellipsometry and ultraviolet–visible (UV–vis) spectrophotometery, respectively. The reflective index of TaO thin films increased with increasing annealing temperature. The result indicated that the annealed TaO thin film showed better performance than the as-deposited film.

Abstract: In this research, NiO/ZnO heterojunction thin films were fabricated on a ITO substrate by a sol–gel technique. The as-prepared thin films were annealed at various temperatures. The effect of annealing temperature on structural, surface morphology and electrical properties of thin films was investigated by XRD, FESEM and I-V characteristic measurement. The XRD results revealed that NiO/ZnO thin film was polycrystalline and exhibited better crystallization when annealing temperature was increased. The current-voltage curve of all sample exhibited the diode behaviour.

Abstract: In this work, cobalt oxide thin films were prepared by electrostatic spray deposition (ESD) technique on glass substrate. The influence of the annealing temperature on properties of cobalt oxide film was investigated. The structural, optical and morphology of cobalt oxide thin films were characterized by X-ray diffraction (XRD), Raman spectroscopy, UV-Visible spectrophotometer, scanning electron microscope, respectively. The crystalline parameters such as crystalline size of films can be obtained from XRD spectra. Phase transformation due to the different annealing temperature in cobalt oxide film has been observed. Moreover, at the higher annealing temperature, the optical band gap in cobalt oxide films were shifted to lower value due to the change in crystalline size and the defect sites in films.

Abstract: In this work, we investigated V₂O₅ thin films prepared by a DC pulse reactive magnetron sputtering at ambient conditions. The effects of oxygen flow rates during the film deposition and post annealing in air atmosphere were explored. The V₂O₅ thin films were sputtered from vanadium target onto silicon wafer and glass slide substrates at room temperature. The as-deposited V₂O₅ thin films were annealed at 200°C under air atmosphere. The films were then examined for their crystallinity, physical microstructures, and optical transmission. The crystallinity and morphology of the films were investigated by grazing incident x-ray diffraction, atomic force microscopy, and field-emission scanning electron microscopy. The optical transmission was determined by UV-Vis Spectrophotometer. The results showed that the as-deposited films were amorphous, whereas the post annealed films indicated V₂O₅ phase in all samples. The increase in the oxygen flow rates during the deposition led to the decrease in the deposition rate, film thickness, and film surface roughness. In addition, the oxygen flow can increase the average transmission of the V₂O₅ thin films. The effects of the annealing treatment of the optical transmission spectra will be discussed.

Abstract: In this work, Zinc oxide (ZnO) thin films were deposited on silicon and glass substrates using spin-coating method with different concentrations of precursor (zinc acetate dihydrate) and stabilizer (monoethanolamine). The concentrations of zinc acetate dihydrate and monoethanolamine in isopropanol were varied from 6 mM to 500 mM. Subsequently, the substrate with ZnO thin film as a seed layer was used to grow ZnO nanostructures by hydrothermal process with the same concentration of precursor (zinc nitrate hexahydrate), temperature, and time for each growth. The samples were characterized by field-emission scanning electron microscopy (FESEM), X-rays diffractometer (XRD), and UV-visible spectrophotometer (UV-vis) to study morphology, crystallographic structure, and optical property, respectively. The results showed that particle size, crystallinity, and transmittance of seed layers were changed with increasing concentrations of spin-coated precursor. Furthermore, the nanostructures were found that higher precursor concentration of seed layers affected the formation of ZnO nanorods to be nanosheets.

Abstract: Ni-doped ZnO thin films were prepared on glass slide substrates by a sol-gel dip coating method with different Ni doping concentrations (0-33 mol%). The effect of Ni doping concentration on structural, surface morphology and optical properties of the thin films was characterized by XRD, FESEM and UV-Vis spectrophotometer. The XRD results indicated that pure ZnO thin film exhibited a hexagonal wurtzite structure. Ni (OH)₂ phase were observed at a high Ni doping concentration. The FESEM images showed that the surface morphology and surface roughness were sensitive to the Ni doping concentration. The optical transmission measurements were observed that the transmittance decreased with increasing the Ni doping concentration.