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https://ptsldigital.ukm.my/jspui/handle/123456789/499551Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Noor Bayaah Ibrahim, Prof. Dr. | - |
| dc.contributor.author | Shereen Mohammad Al-Shomar (P60023) | - |
| dc.date.accessioned | 2023-10-13T09:32:45Z | - |
| dc.date.available | 2023-10-13T09:32:45Z | - |
| dc.date.issued | 2015-03-19 | - |
| dc.identifier.other | ukmvital:80061 | - |
| dc.identifier.uri | https://ptsldigital.ukm.my/jspui/handle/123456789/499551 | - |
| dc.description | Zinc oxide thin films were prepared by sol-gel method on quartz substrates. The effects of annealing temperature (500, 600, and 700 °C) and sol aging time (1, 7, and 11 days) on the structural, optical, electrical, magnetic and photoluminescence properties of the films were investigated. X-ray diffraction (XRD) analysis showed that the deposited films were polycrystalline with a hexagonal wurtzite structure, oriented along the c-axis direction. Both annealing temperature and aging time affected the grain size and films thickness, which were measured using a field emission scanning electron microscope (FESEM). The grain size was in the range of 21-60 nm and the film thickness was in the range of 55-170 nm. The roughness of ZnO film which was investigated by an atomic force microscopy (AFM) showed that the films were smooth or rough, depending on the changes of grain size. The optical properties were studied by a UV-Vis-NIR spectroscopy. The results showed that the films exhibited high transmittance (above 90%) in the visible range, and the absorption edge was approximately 360 nm. The measured optical band gap values of the ZnO films were between 3.06 eV and 3.38 eV. The electrical resistivity values which were determined using an I-V measurement was in the range of 5.16 × 10-2 to 30.14 × 10-2 Ω.cm. The photoluminescence intensity, characterized using photoluminescence spectroscopy, also improved with the increase in annealing temperature and aging time. The ZnO films showed ultraviolet, violet and green emissions. Gd doped with ZnO at 0.01, 0.03, and 0.05 mol/L doping concentrations and Nd doped with ZnO at 0.015, 0.037, and 0.05 mol/L doping concentrations were also investigated. The Gd doped ZnO and Nd doped ZnO films have hexagonal wurtzite structure; no peaks corresponding to Gd or Nd were observed in the XRD patterns. After doping with Gd or Nd, the grain size, films thickness and surface roughness change depending on doping concentration. The doped ZnO films displayed high transmittance in the visible range, and the optical band gap values in general increased with doping concentration. The doped ZnO films also showed low electrical resistivity at high doping concentration and high annealing temperature (2.3 × 10-3 Ω.cm for Gd doped ZnO and 3.7 × 10-3 Ω.cm for Nd doped ZnO). The doped films exhibited magnetic properties, which can be attributed to defects such as oxygen vacancy. Doping with Gd and Nd ions also affected the photoluminescence spectra of the ZnO films. The increase in doping concentration has a direct effect on the intensity of green and blue emissions. Annealing at 500, 600, and 700 °C affected the grain size, film thickness and increased the surface roughness of Gd doped ZnO and Nd doped ZnO films. The determined optical band gap values were in range of 3.22 to 3.40 eV, and the electrical conductivity increased with annealing temperature. Results suggest that Gd and Nd doping improved the optical, electrical, magnetic and photoluminescence properties of ZnO thin films. Thus, Gd doped ZnO and Nd doped ZnO films have potential application in optoelectronic and spintronics devices.,Ph.D. | - |
| dc.language.iso | eng | - |
| dc.publisher | UKM, Bangi | - |
| dc.relation | Faculty of Science and Technology / Fakulti Sains dan Teknologi | - |
| dc.rights | UKM | - |
| dc.subject | Thin film | - |
| dc.subject | Quartz substrates | - |
| dc.subject | Zinc oxide | - |
| dc.title | Physicocemical properties of ZnO, Gd and Nd doped ZnO thin films prepared by sol-gel method | - |
| dc.type | Theses | - |
| dc.format.pages | 203 | - |
| dc.identifier.barcode | 002008(2016) | - |
| Appears in Collections: | Faculty of Science and Technology / Fakulti Sains dan Teknologi | |
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| File | Description | Size | Format | |
|---|---|---|---|---|
| ukmvital_80061+SOURCE1+SOURCE1.0.PDF Restricted Access | 1.54 MB | Adobe PDF |  View/Open |
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