Defect Induced Room Temperature Ferromagnetism in Well-Aligned ZnO Nanorods Grown on Si (100) Substrate

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

ABSTRACT 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.

1 Follower
8 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, vertically aligned ZnO nanowire arrays were synthesized by a simple hydrothermal process. The microstructure, morphology, magnetic and optical properties of the as-prepared samples were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), vibrating sample magnetometer(VSM) and photoluminescence spectrum (PL). The results show that the vertically aligned ZnO nanowire arrays are hexagonal wurtzite structures with the high (002)-orientation. At room temperature, all the samples possess ferromagnetism with the saturation magnetic moment of 0.1443 emu/g. The PL measurements illustrate that the as-prepared ZnO nanowire arrays exhibit a strong yellow-green emission centered at about 550 nm and a weak near-ultraviolet (UV) emission at about 375nm. A possible origin of ferromagnetism and yellow-green emission of the ZnO nanowire arrays related to the intrinsic defect is proposed.
    Nanotechnology (IEEE-NANO), 2012 12th IEEE Conference on; 01/2012
  • Source
    [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
Show more