School of Nano and Advanced Materials Engineering, Changwon National University, Changwon, Gyeongnam, 641-773, Republic of Korea
Thin Solid Films (Impact Factor: 1.76). 09/2011; 519(23). DOI: 10.1016/j.tsf.2011.03.062
In this work, we report the fabrication of high quality single-crystalline ZnO nanorod arrays which were grown on the silicon (Si) substrate using a microwave assisted solution method. The as grown nanorods were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL) and magnetization measurements. The XRD results indicated that the ZnO nanorods are well oriented with the c-axis perpendicular to the substrate and have single phase nature with the wurtzite structure. FE-SEM results showed that the length and diameter of the well aligned rods is about similar to 1 mu m and similar to 100 nm respectively, having aspect ratio of 20-30. Room-temperature PL spectrum of the as-grown ZnO nanorods reveals a near-band-edge (NBE) emission peak and defect induced green light emission. The green light emission band at similar to 583 nm might be attributed to surface oxygen vacancies or defects. Magnetization measurements show that the ZnO nanorods exhibit room temperature ferromagnetism which may result due to the presence of defects in the ZnO nanorods.
"The UV emission band is usually attributed to the near-band edge emission of the wide band gap of ZnO due to the annihilation of excitons [8, 19–21]. The visible emission is the most commonly observed and is often attributed to the defect emission      . It is known that different defects may cause different electronic structures, which will be reflected on the corresponding optical properties observed in experiments. "
[Show abstract][Hide abstract] ABSTRACT: Well-aligned ZnO nanorod arrays with room temperature ferromagnetism were prepared on glass substrate through hydrothermal method. The as-prepared nanorod arrays were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), photoluminescence (PL) spectrum, and magnetization measurements. The XRD and SEM results indicated that the ZnO nanorods are with the wurtzite structure and exhibit preferential (002) orientation with -axis perpendicular to the substrate surface. The PL results suggested that the possible defect in the as-prepared ZnO nanorod arrays might be , , or . The first-principles calculations reveal that the room temperature ferromagnetism may result from the defects present in the ZnO nanorod and the hybridization of the Zn 3d states with O 2p states is responsible for the half-metallic ferromagnetism in ZnO nanorod.
[Show abstract][Hide abstract] ABSTRACT: The production level of food grains has become an issue of concern as it has been showing a downward trend over the last decade. Since, there has been a drastic decrease in natural resources; it is through agriculture that we can visualize a self sustainable world. The growth in agriculture can be achieved only by increasing productivity through an effective use of modern technology as the land and water resources are limited. Nanobiotechnology provides the tool and technological platforms to advance agricultural productivity through genetic improvement of plants, delivery of genes and drug molecules to specific sites at cellular levels. The interest is increasing with suitable techniques and sensors for precision in agriculture, natural resource management, early detection of pathogens and contaminants in food products and smart delivery systems for agrochemicals like fertilizers and pesticides. To achieve the goals of “nano- agriculture”, detailed investigation on the ability of nanoparticles to penetrate plant cell walls and work as smart treatment-delivery systems in plants is needed. In this chapter, thorough studies and reliable information regarding the effects of nanomaterials on plant physiology and crop improvement at the organism level are discussed.
[Show abstract][Hide abstract] ABSTRACT: We have successfully synthesized large-scale aggregative flowerlike Zn1-xCo(x)O (0.0 < or = x < or = 0.07) nanostructures, consisting of many branches of nanorods at different orientations with diameter within 100-150 nm (tip diameter approximately 50 nm) and length of approximately 1 microm. The rods were prepared using Zinc nitrate, cobalt nitrate and KOH in 180 Watt microwave radiation for short time interval. The synthesized nanorods were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM) and DC magnetization measurements. XRD and TEM results indicate that the novel flowerlike nanostructures are hexagonal with wurtzite structure and Co ions were successfully incorporated into the lattice position of Zn ions in ZnO matrix. The selected area electron diffraction (SAED) pattern reveals that the nanorods are single crystal in nature and preferentially grow along [0 0 1] direction. Magnetic studies show that Zn1-xCo(x)O nanorods exhibit room temperature ferromagnetism. This novel nanostructure could be a promising candidate for a variety of future spintronic applications.
Journal of Nanoscience and Nanotechnology 02/2012; 12(2):1386-9. DOI:10.1166/jnn.2012.4631 · 1.56 Impact Factor
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