Muhammad Rizwan,
Volume 22, Issue 1 (3-2025)
Abstract
Powder-based Physical Vapor Deposition (PPVD) was utilized to deposit doped TiO2 thin layers, to modify electronic and optical properties. The modification was performed using different dopants (MnO2, Ta2O5, Nb2O5) at different concentrations (0.05 and 0.1 mol%) respectively. The structural characterization by FESEM reveals that the size of the grain varied with respect to the dopants. The sample doped at lower concentration demonstrates a larger crystallite size than the sample doped at higher concentration. This trend is consistent with the measured grain size of the doped thin layer samples. The nonlinearity coefficient (α) and breakdown voltage at lower ranges are enhanced as the dopant concentration in the TiO2 lattice increases due to the reduction of grain size. While, the optical properties of doped TiO2 thin layers with respect to energy bandgap demonstrated enhancement trend with the addition of the dopant as revealed by UV-Vis’s reflectance analysis. The enhancement of electrical and optical properties is contributed by the formation of barrier layer surrounding the grains, which in return increases the conductivity of the doped TiO2 thin layers sample. Conclusively, this study demonstrates the feasibility of the PPVD method in producing a dense thin layer structure for further optical and electrical based applications.
Adil Kadum Shakir, Ebrahim Ghanbari-Adivi, Aref S. Baron Baron, Morteza Soltani,
Volume 22, Issue 1 (3-2025)
Abstract
Nanomaterials have significantly transformed multiple scientific and technological fields due to their exceptional properties, which result from their quantum confinement effects and high surface-to-volume ratios. Among these materials, zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles have attracted considerable interest because of their diverse applications.
In this study, TiO2-ZnO nanocomposites were synthesized using varying calcination times of 1, 1.5, 2, 2.5, and 3 hours. Characterization of fabricated samples through X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDXS) confirmed the successful fabrication of the nanocomposites. In this regard, XRD analysis revealed anatase TiO2 and hexagonal wurtzite ZnO phases. Raman spectroscopy also supported these findings, identifying characteristic peaks of both TiO2 and ZnO.
The calcination time had a minimal effect on the crystal structures and also morphology of the nanocomposites, which gave rise to its negligible impact on optical properties and biological activities of the samples. Optical properties assessed by means of UV-visible and photoluminescence (PL) spectroscopy showed consistent band gap absorption and emission profiles across all samples, among which the nanocomposite calcined for 1 hour exhibited the best optical properties.
The sample prepared at 1 hour not only showed the most favorable optical properties, but also demonstrated significant antibacterial, antifungal, and cytotoxic activities, which make it suitable for various applications. In this regard, a reduction of more than 99.9% occurred in the number of Escherichia coli and Staphylococcus aureus bacteria and also Candida albicans fungus by using TiO2-ZnO nanocomposite. Besides, addition of 500 µg/ml of nanocomposite decreased the cell viability to 34.47%, which signifies its high cytotoxicity activity.
