Papers by Author: Ruziana Mohamed

Abstract: This paper reports the properties of Bi-2223 superconductors that had been doped with Fe₂O₃ at Cu-site of the system. It was prepared in bulk form using high purity oxide powders via solid state reaction technique with intermediate grinding. A series of x = 0.00, 0.02, 0.04, 0.06, 0.08 and 0.10 of Fe were stoichiometrically added to the well balanced of Bi_1.6Pb_0.4Sr₂Ca₂Cu_3-xFe_xO_y in order to trace the effect of Fe doping. Hence, electrical resistivity, X-ray diffraction and Field Emission Scanning Electron Microscopy have been carried out to assess the effects of Fe doping. These measurements indicate that Fe doping decreased the critical temperature and degrade the formation of high T_c phase compared with the undoped sample. The orthorhombicity parameters were increased due to substitution of Cu ³⁺ ion by Fe ²⁺ ion.

Abstract: Tin oxide (SnO₂) nanostructured thin film with different immersion times was prepared on zinc oxide (ZnO) seeded catalyst using immersion method. The immersion times were varied at 3.0, 3.5 and 4.0 hours. Field emission scanning electron microscopy (FESEM) and two point probes current-voltage (I-V) measurements were used to study the surface morphology and electrical properties of SnO₂ nanostructured thin films. The diameter size of SnO₂ nanostructures which immersed at 3.0, 3.5 and 4.0 h were in range 10-20 nm, 20-30 nm and 30-50 nm, respectively. The results shows the highest electrical properties was at 3.0 h of immersion time.

Abstract: Mg doped Zinc oxide nanorods films were successfully deposited on glass substrate prepared by aqueous solution-immersion method. The influence of annealing temperature on the nanorod films were studied at different annealing temperatures 0°C, 250°C and 500°C respectively. FESEM showed the morphology of the films with hexagonal nanorods growth. XRD results indicated the crystalline structure of ZnO doped Mg nanorods films where the peak intensity of ZnO was decreased as annealing temperature increases. Photoluminescence (PL) measurement at room temperature showed the increasing of intensity peak for visible spectra with increasing of annealing temperature.

Abstract: Mist-atomization deposition method was applied in order to grow ZnO nanoparticles on Au-seeded glass substrates acting as seeded template. Ag doped ZnO thin films were deposited on ZnO seeded templates by solution-immersion method. The influence of Ag doping content on the optical and Raman scattering properties of ZnO films were systematically investigated by UV-Vis transmittance measurement measured by ultra-violet visible spectroscopy (UV-Vis) and Raman scattering spectrum measured by Raman spectroscopy under room temperature. From UV-Vis transmittance measurement, the incorporation of Ag dopant to the ZnO makes the transmittance wavelength shifted to the shorter wavelength as compared to the pure ZnO. From Raman spectra, 4 cm^-1 downshift is observed in Ag-doped thin films as compared to pure ZnO thin films. This Raman peak shift shows that a tensile stress existed in the Ag-doped ZnO film.

Abstract: Different layers of PMMA spin coated onto substrate were successful prepared by sol-gel spin-coating method. PMMA was dissolved in toluene solvent and was aged for 24 hours to produce the homogeneous solution. The films were then characterized by Raman Spectroscopy and Ultraviolet-Visible (UV-Vis) spectroscopy. Raman spectroscopy studied reveals the 7 layers of PMMA film exhibit the strong and sharp intense peak at observed band around 810 cm^-1 that is due to the symmetric CC₄ stretching. The UV-Vis measurement present 7 layers of PMMA film have good absorption due to the small size of particles and uniform surface of the film.

Abstract: In this studies, we present different layers of PMMA films spin coated onto glass substrate by using sol-gel spin-coating method. Atomic Force Microscope (AFM) reveals the surface morphology of the samples uniformly distribute on the substrate. 1 layer sample show white particles of PMMA clearly spread on the substrate and become closely-packed after the layer of PMMA increase to 3, 5 and 7 layers. 7 layers completely dense surface morphology due to the excessive number of the particles of PMMA in the sample. The approximate roughness was recorded between ranges 0.10 – 0.25 nm. Raman spectra shown 7 layers of PMMA films as the lowest Raman intensity with strong and intense peak at band about 1024 cm^-1 which is probably due to the excessive number of particles and rougher surface present in the sample.

Abstract: Mist-atomization deposition method was applied in order to grow ZnO nanostructures with various surface morphologies. ZnO was deposited from the mixture of zinc nitrate hexahydrate (Zn (NO₃)₂.6H₂O) and stabilizer, hexamethylenetetramine (HMTA, C₆H₁₂N₄) aqueous solutions onto Au-seeded glass substrate. The mixture was sprayed onto the surface of Au-seeded glass substrate at various growth temperatures of room temperature (RT), 100, 200, and 300 °C. The obtained structures were characterised by room-temperature photoluminescence (PL), field emission scanning electron microscopy (FESEM), and UV-VIS-NIR spectrophotometer. It is found that ZnO growth on 300 °C substrate temperature shows the best absorbance properties and highest UV emission peak with denser distribution amongst all. The optical and morphological properties of sprayed ZnO nanostructures largely depend on the substrates temperature during spraying the zinc nitrate solution and on the Au-seeded glass substrates.

Abstract: ZnO nanostructures were obtained by mist-atomisation technique. Nanostructured ZnO can be grown in aqueous solution of zinc nitrate hexahydrate as precursor solution with the addition of stabilizer hexamethylenetetramine (HMTA). ZnO nanostructures deposited by mist-atomisation, with applied heat from the glass substrates’ downside. Firstly, the glass substrates were seeded by Au with different thickness of 0 (non-seeded), 6, and 12 nanometer (nm). The growth of ZnO on different Au-seeded thickness is studied. The optical properties of ZnO nanostructures were examined by Ultraviolet-Visible (UV-Vis) spectroscopy. The morphology of the ZnO thin films obtained was studied by FESEM. FESEM micrographs shows different nanostructures formed on different thickness of Au-seeded glass. UV-vis spectra of ZnO nanostructures display high absorption in the UV region and high transparency in the visible region. There is improvement in UV absorption for ZnO growth on 6nm Au-seeded compared to non-seeded and 12 nm Au-seeded glass due to imperfect alignment of ZnO nanostructures.

Abstract: Tin-doped Zinc Oxide (Sn-doped ZnO) thin films were prepared using zinc nitrate hexahydrate as a starting material by sol-gel immersion method. The synthesized samples were characterized by current-voltage (I-V) measurement and Field Emission Scanning Electron Microscopy (FESEM). The Sn doping concentration were varied at 1.0 at.%, 2.0 at.%, 3.0 at.% and 4.0 at.%. FESEM images show that as the Sn concentration increased, the nanoparticles size of Sn-doped ZnO become denser and less grain boundary which might help in improvement of the electrical properties.

Abstract: Tin-doped Zinc Oxide (Sn-doped ZnO) thin films were prepared using zinc nitrate hexahydrate as a starting material by sol-gel immersion method. Then the synthesized samples were characterized by current-voltage (I-V) measurement and FESEM. The Sn doping concentration were varied at 0.2 at.%, 0.4 at.%, 0.6 at.%, 0.8 at.% and 1.0 at.%. The result suggests that the optimum value for Sn doping concentration was 0.8 at.% which exhibited the highest conductive sample with value of 3.00 ×10^-6 S/cm.