الفهرس | Only 14 pages are availabe for public view |
Abstract Flower-shaped Zinc oxide (ZnO) nanowires were synthesized by sol-gel dip-coating. Sol-gel was prepared with different concentrations: 0.003M, 0.005M, 0.007M, 0.01M, and 0.02M from aqueous solutions of zinc nitrate hexahydrate and methenamine at different acidities: pH 7, pH 6, and pH 4. The dip-coating process was performed on substrates: Si, and SiOR2R. The coating time was varied from 30 min to 48 hours. The coating processes were done at different temperatures: 70 P o PC, 80 P o PC, and 90 P o PC. Characterization of the surface morphology and crystal structure of ZnO thin films was carried out using many techniques: field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The optical properties were also studied by photoluminescence (PL) measurements. FESEM showed that the product is hexagonal flower-shaped ZnO nanowires. We found that the best times for coating ranges from 2 to 4 hours, with increasing in the nanowires diameter as the coating time increases. Also, there was an observable increase in diameter either with increasing the molar concentration or with increasing the coating temperature. For low concentrations there was a dramatic decrease in deposition of the nanowires at 70 P o PC and 80 P o PC. Preparation of the sol-gel in acidic solution (pH = 6 and pH = 4) doesn’t affect on the nanowires diameter but affects on their outer shape. Nanowires prepared from acidic solutions were found to have a uniform diameter from top to bottom, whereas those prepared from neutral sol yielded non-uniform diameters; small at the top and large at the bottom. The energy dispersive X-ray (EDX) showed that the composition of the nanowires was zinc and oxygen with weight percentage of 78.03% and 21.97% respectively, and atomic percentage of 46.51% and 53.49%, respectively. |