M. Rasheed | Searcharxiv

arXiv2018

Cu:ZnO deposited on porous ceramic substrates by a simple thermal method for photocatalytic application

Thin films of undoped zinc oxide (ZnO) and doped ZnO with copper were deposited on ceramic pellets made from abundant local clay materials with an addition of zirconia (ZrO2). The thin layers were prepared by a thermal method using an autoclave. The resulting structural and morphological properties of the products were studied in order to determine the effectiveness of their photocatalytic activities. X-ray diffraction, Scanning Electron Microscopy, energy-dispersive X-ray spectroscopy and UV-visible spectrophotometry were used in this goal. An application test was carried out to quantify the photocatalytic degradation of a toxic organic dye by these samples under UV light. In similar conditions, the layers deposited on the ceramics with addition of zirconia have shown better performances than those without zirconia. This result can be related to the porosity created when the zirconium oxide reacted with SiO2 of the clay. The open porosity observed on this type of substrate allows a larger surface for the photocatalysis. The degradation rate of the dye reached 90.5 % during a period of 7 hours with Cu doped ZnO thin layers deposited on porous substrates modified with addition of ZrO2.

physics.chem-ph↗

arXiv2017

Comparison the optical properties for Bi2O3 and NiO ultrathin films deposited on different substrates by DC sputtering technique for transparent electronics

Bismuth and Nickel transparent oxides thin films were grown on glass and flexible polythelene terephalate (PET) substrates by DC sputtering technique at room temperature 300 K. The structures of Bi2O3 and NiO films were analyzed by X-ray diffraction (XRD) analyses and scanning electron microscopy (SEM). A profilometry is used to measure the thicknesses of the ultrathin films. These values were established by a spectro-ellipsometry technique with a new amorphous dispersion model in the range of 200 nm to 2200 nm with one nm increment. In addition, the optical constants of these films were investigated using a double beam UV-Vis-NIR spectrometer and a spectro-ellipsometry and compared using the same wavelength range. They present an excellent agreement. According to the optical transmittance spectra of the films a high average transmittance in the visible region of each sample deposited onto different substrates is measured. Moreover, the absorption coefficients and the optical energy gaps for four types of optical transitions (allowed direct, forbidden direct, allowed indirect, forbidden indirect) of the films were determined and compared with the two different techniques. Finally, the nature of the structure and morphology of Bi2O3 and NiO ultrathin films has been analyzed and compared.

physics.app-ph↗