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55 From helical nanowires, nanocrosses to aligned micro-carbon fibers
Author(s): Hai-Feng Zhang (Affiliation: Dept. of Phys., Washington State Univ., USA), Chong-Min Wang, J.S. Young, J.E. Coleman, Lai-Sheng Wang
Editor(s): O.D.Velev, T.J.Bunning, Y.Xia, P.Yang
Conference: Unconventional Approaches to Nanostructures with Applications in Electronics, Photonics, Information Storage and Sensing Symposium, San Francisco, CA, USA
Conference Date: 21-25 April 2003
Publication: Unconventional Approaches to Nanostructures with Applications in Electronics, Photonics, Information Storage and Sensing Symposium (Mater. Res. Soc. Symposium Proceedings Vol.776)
Publisher: Mater. Res. Soc, USA, 2003
Language: English
ISBN: 1 55899 713 X Page: 95-100
Document type: Conference paper
Abstract: We successfully synthesized helical core-shell crystalline SiC/SiO 2 nanowires, core-shell crystalline SiC/C nano-crosses and well-aligned core-shell crystalline SiC/C fibers by using a chemical vapor deposition technique. For the helical crystalline SiC/SiO2 nanowires, the SiC core typically has diameters of 10-40 nm with a helical periodicity of 40-80 nm and is covered by a uniform layer of 30-60 nm thick amorphous SiO2. Detailed structural characterizations suggested that the growth of this novel structure was induced by screw dislocations on the nanometer scale. For the coreshell nanocrosses, the crystalline SiC core typically has diameters of 10 to 40 nm and is covered by a uniform layer of 80-110 nm graphitic carbon. The well-aligned SiC/C fibers were shown to be formed by two sequential steps: catalytic SiC growth and graphitic carbon nano-sheets coating. The helical nanowires and core-shell nanocrosses may have potential applications in nano-electronics. The formation mechanism of the carbon fibers suggested that fabrication of field emission filament carbon nano-fibers may be realized by using the aligned crystalline nanowires as templates (8 refs.)
Inspec No.: 8253434
56 Growth and characterization of ZnO nanowires
Author(s): J.B. Baxter, R.E.M.W. Bessems, E.S. Aydil (Affiliation: Dept. of Chem. Eng., Santa Barbara Univ., CA, USA)
Editor(s): O.D.Velev, T.J.Bunning, Y.Xia, P.Yang Conference: Unconventional Approaches to Nanostructures with Applications in Electronics, Photonics, Information Storage and Sensing Symposium, San Francisco, CA, USA
Conference Date: 21-25 April 2003
Publication: Unconventional Approaches to Nanostructures with Applications in Electronics, Photonics, Information Storage and Sensing Symposium (Mater. Res. Soc. Symposium Proceedings Vol.776)
Publisher: Mater. Res. Soc, USA, 2003
Language: English
ISBN: 1 55899 713 X Page: 101-6
Document type: Conference paper
Abstract: Single crystal ZnO nanowires were grown by chemical vapor deposition using monodisperse 5 nm or 20 nm diameter gold nanoparticle catalysts to control the nanowire diameter and location. The nanowires reach several microns in length and grow only from the gold nanoparticles. The nanowires have narrowly dispersed diameters, albeit significantly larger than the diameter of the gold particles used for catalyzing the growth. The nanowires grow in the [101¯0] or [101¯1] directions normal to the lowest energy planes in ZnO nanowires emit in the near ultraviolet region of the electromagnetic spectrum upon excitation with high-energy photons or electrons. Electron diffraction and absence of luminescence associated with oxygen vacancies indicate high quality crystalline ZnO nanowires. Cathodoluminescence emission along the entire length of the wire is consistent with a lack of non-radiative recombination sites associated with defects, lending further support for the high quality of these nanowires (11 refs.)
Inspec No.: 8253435
57 Catalytic growth of semiconducting ZnO nanowires by reactive evaporation process
Author(s): Joodong Park, Han-Ho Choi, R.K. Singh (Affiliation: Dept. of Mater. Sci & Eng., Florida Univ., Gainesville, FL, USA)
Editor(s): O.D.Velev, T.J.Bunning, Y.Xia, P.Yang
Conference: Unconventional Approaches to Nanostructures with Applications in Electronics, Photonics, Information Storage and Sensing Symposium, San Francisco, CA, USA
Conference Date: 21-25 April 2003
Publication: Unconventional Approaches to Nanostructures with Applications in Electronics, Photonics, Information Storage and Sensing Symposium (Mater. Res. Soc. Symposium Proceedings Vol.776)
Publisher: Mater. Res. Soc, USA, 2003
Language: English
ISBN: 1 55899 713 X Page: 107-12
Document type: Conference paper
Abstract: Reactive evaporation process was introduced as a simple technique for the fabrication of aligned ZnO nanowires on a Si(100) surface. Single crystalline ZnO nanowire arrays were successfully synthesized on Au coated Si substrates via a VLS growth mechanism. The diameter of ZnO nanowires were observed to vary from 40 nm to 150 nm and the ratio of length to diameter was observed to be larger than 30. The diameter of ZnO nanowires was controlled by changing the processing temperature and by the thickness of Au catalyst film. Green emission induced from singly ionized oxygen vacancies was generated from ZnO nanowires with the excitonic emission in UV range. Higher intensity of the green emission was observed in thinner nanowires, which is attributed to their higher surface-to-volume ratio. Aligned structure formation and size control of ZnO nanowires could provide the potential for various nano-scale device applications (15 refs.)
Inspec No.: 8253436
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