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Fabrication And Characterization Of One-dimensional Functional Nanomaterials

Posted on:2007-12-28Degree:DoctorType:Dissertation
Country:ChinaCandidate:J Z LiuFull Text:PDF
GTID:1101360182494226Subject:Condensed matter physics
Abstract/Summary:PDF Full Text Request
Against the background of preparation and application of nanomaterials, this article reports on the latest progress in research of nanomaterials and our research achievements with the emphasis of preparing one-dimensional nanomaterials. The contents are as follows.1. Carbon nanotubes have the defects of easily bending and entangling with each other. Many organic or inorganic materials could be coated on the surface of carbon nanotube. However, most of the coatings are amorphous or poly-crystalline. We have synthesized multiwall carbon nanotubes and attempted to coat single-crystals on the surfaces of carbon nanotubes to form nanotube-monocrystalline-coating composite rods. In our experiment, single-crystalline Zn(BO2)2 coating was successfully overgown onto the surfaces of carbon nanotubes. For the first time, the growth of monocrystalline coating on the surface of carbon nanotube was found to bring on a stress which made the curly tube straight. According to the experimental results, we qualitatively explained straightening mechanism and elucidated the relation between the straightening effect and the curvature of the bend carbon nanotube segment.2. Porous adonic aluminum oxide templates are widely used to fabricate nanowires or nanotubes of many materials. We have prepared porous alumina templates using oxalic acid as electrolyte. The membrane prepared through a two-step oxidation process has regular-arranged nanopores. The channels of the template are parallel and the diameters of the nanopores are uniform, which could be altered in the range of 30-100 nm by enlarging treatment, In addition, the amorphous alumina template was nitridized to be spinel aluminum oxynitride (Al2O3.AlN) with a simple method.3. Sn naowire arrays were AC electrodeposited into the pores of anodic aluminum oxide template. TEM was used to characterize the Sn nanowires. After removing the alumina template by phosphoric acid, the Sn nanowire arrays attachaing to Al sheets were thermally oxidized into SnO2 nanowire arrays. Using the SnO2 nanowire array as substrate, diamond-like carbon was low-voltage electrodeposited out of the electrolyte of a mixture of acetate acid and deioned water.4. With the method of thermally evaporating SnO2 powder, SnO2 nanowires were grown via vapor-liquid-solid mechanism. The substrates were porous alumina templates with Au-particle arrays on the surfaces. The nanowires have a high aspectratio, and their diameters are about 50nm in average.5. Using the substrate of graphite sheet or porous alumina template with Au particles on the surface, poly-morphous undoped or Cd-doped ZnO one-dimensional nanostructures were grown. The effect of temperature on the morphologies of the ZnO nanostructures was studied. The optical properties of these ZnO one-dimensional nanostructures were studied with photoluminescence measurements and found to have strong green light emissions. The emission band from Cd-doped ZnO shows red-light shift.6. Using Zn and S as precursors, poly-morphous doped ZnS one-dimensional nanostructures, such as nanowires and nanobelts, were fabricated through a vapor deposition process. The doping elements are Mn, Cd, Cu, Fe, Ni and Sb, etc. Photoluminescence measurement was used to study the optical properties of these doped ZnS nanostructures. Meanwhile, Mn and Cd co-doped ZnS shows a red-light emission. We discussed the mechanism of this red-light emission based on experimental results.
Keywords/Search Tags:One-dimensional nanostructures, Semiconducting materials, Electrodeposition, Chemical vapor deposition.
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