Authors: Feng Feng Li, Chao Ling Li, Ming Xi Zhang, Yi Shen
Abstract: Well-aligned ZnO nanorod arrays with 100-200nm diameter and about 1μm length were vertically grown on quartz substrate at relatively low temperature by a solution deposition method. The effects of reactant ratio, water-bath temperature, growth time on crystal structure were discussed. Microstructure of the arrays was investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), optical properties were examined using fluorescence spectrophotometer. The results show that a Zn/C6H12N4 molar ratio of 1:1, bath temprature 70°C, growth time of 24h are the optimal condition for the preparation of densely distributed ZnO arrays. XRD and FE-SEM analysis confirmed that the ZnO nanorod is a single crystal with a wurtzite structure and the photoluminescence (PL) spectra exhibit coexistence properties of ultraviolet (UV), blue and green emissions.
1605
Authors: Nur Syafinaz Ridhuan, Yeo Pet Fong, Zainovia Lockman, Abdul Razak Khairunisak
Abstract: In this study, ZnO nanorods was formed on a seeded substrates prepared by thermal oxidation of Zn foil followed by hydrothermal reaction. ZnO seed was prepared via thermal oxidation process at 300°C for 10 minutes to form uniform circular nanosize grains that were suitable as a seeded template for the growth of ZnO nanorods via hydrothermal reaction. Several hydrothermal reaction parameters were studied; hydrothermal reaction temperature, ratio of zinc nitrate to hexamethylamine and pH. In hydrothermal reaction, the formation of ZnO nanorods occurs due to thermal degradation of hexamethylamine (HMT) which released hydroxyl ions that react with Zn ions in the precursor solution. Well aligned, ZnO nanorods with length of ~700 nm, base diameter of ~200 nm and top diameter of less than 30 nm needle-like structure were formed on seeded Zn substrate with concentration ratio of zinc nitrate to hexamethylamine 0.1M:0.1M, pH 6-7 at hydrothermal reaction temperature of 80°C
116
Authors: Azlinda Ab Azlinda, Zuraida Khusaimi, Saifollah Abdullah, Mohamad Rusop
Abstract: Zinc oxide (ZnO) nanostructures prepared by immersion method were successfully grown on gold-seeded silicon substrate using Zinc nitrate hexahydrate (Zn (NO3)2.6H2O) as a precursor, separately stabilized with non-toxic urea (CH4N2O) and hexamethylene tetraamine (HMTA). The effect of changing the stabilizer of ZnO solution on the crystal structure, morphology and photoluminescence properties of the resultant ZnO is investigated. X-ray diffraction of the synthesized ZnO shows hexagonal zincite structure. The morphology of the ZnO was characterized using Field Emission Scanning Electron Microscope (FESEM). The growth of ZnO using urea as stabilizer shows clusters of ZnO nanoflower with serrated broad petals were interestingly formed. ZnO in HMTA showed growth of nanorods. The structures has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors. The formation of ZnO nanostructures is found to be significantly affected by the stabilizer.
45
Authors: P. Suresh Kumar, A. Dhayal Raj, R. Suresh, D. Mangalaraj
Abstract: Intensive and innovative research is focused on the preparation of various nanostructured materials especially nanostructured metal oxides as applicable to number of applications.The present work mainly emphasis a single step synthesis of ZnO nanoparticles by employing surfactant free forced condensation method. Surface morphology of the sample was precisely controlled by varying the calcination conditions. Investigation on the structure, surface and composition of ZnO nanoparticles is of both fundamental interest and technological importance. X-ray diffraction (XRD) analysis reviled that the ZnO nanoparticles exhibits crystalline with the preferential orientation along (1 0 0) plane. SEM image shows the nanoparticles are in the range of 75 to 150 nm with spherical shape. The room temperature PL spectra of ZnO particles exhibited strong ultraviolet photoluminescence around 380 nm at room temperature.
86
Authors: Kugalur Shanmugam Ranjith, Ramanathaswamy Pandian, Gomathi Natarajan, Mohammed Kamruddin, Ramasamy Thangavelu Rajendrakumar
Abstract: Synthesis of aligned ZnO nanorods (NRs) is important for electronic and optoelectronic devices. In this work we demonstrate the growth of ZnO nanorods by co-precipitation method using zinc nitrate and hexamine precursors. The samples were characterized by X-ray diffraction analysis, Scanning electron microscopy and Raman spectroscopy. On introducing the seeded substrate into the growth solution, the seeds offer nucleation sites for one-dimensional growth of ZnO nanorods. ZnO nanorod arrays grown on the successive ionic layer adsorption and reaction (SILAR) seed layer found to be irregular and non-uniform due to the etching of the seed substrate by growth solution. However, dip-coated seed substrate yielded uniform growth of ZnO nanostructures. ZnO nanostructures with flower-like morphology were obtained for pH of 9. On reducing the pH of the growth solution the flower morphology transformed into rod-like morphology with rod diameter of 200nm. On reducing the pH to 3 the diameter of the nanorods is decreased to 20 to 25nm. On reducing the precursor concentration the faceted morphology of the nanorods changed into needle-like shape (with sharp tips) along with reduction in diameter (about 20nm). The growth of uniform and vertically aligned ZnO nanorods is observed in dip-coated seed substrate with 5 pH. The results indicate that the diameter of ZnO nanorod array could be controlled by varying the precursor concentration.
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