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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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Author: search.filters.author.Kuo, CTSubject: search.filters.subject.catalyst

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    Effects of substrate pretreatments and catalyst applications on Si-C-N films and nanotube formations
    (2001-12-01)
    Chang, HL
    ;
    Kuo, CT
    ;
    材料科學與工程學系
    ;
    Department of Materials Science and Engineering
    The Si-C-N films were synthesized on Si substrates by a microwave plasma chemical vapor deposition (MPCVD) system with CH4, H-2 and N-2 as the source gases. Metal coating on Si columns were placed around the specimen and acted as catalyst and additional source of Si. Some of the Si substrates were mechanically polished or chemically etched with HF-KIO3-H2O solutions to obtain different surface roughness before film depositions. Effects of the substrate pretreatment and the action of catalysts on surface morphologies, compositions, band structure, field emission of the films were examined. Nanotubes or nanowires structures were found for films deposited on no-treatment substrate using Fe, Co and Pt catalysts. However, chemical etching substrate can enhance formation of crystals and film nucleation with or without the addition of catalyst. This was the first work to demonstrate the possibility of fabricating the Si-C-N nanotubes through use of the catalysts and by controlling the deposition conditions by MPCVD. Under the present deposition conditions and by using Fe catalyst, the lowest turn-on voltage of the films can be as low as 1.3 V/mum, while the corresponding emission current density at field strength of 20 V/mum can go beyond 2000 muA/cm(2).
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    Feasibility studies of magnetic particle-embedded carbon nanotubes for perpendicular recording media
    (2003-03-01)
    Kuo, CT
    ;
    Lin, CH
    ;
    Lo, AY
    ;
    材料科學與工程學系
    ;
    Department of Materials Science and Engineering
    Nano-sized magnetic particles were successfully used as the catalysts to synthesize magnetic metal-encapsulated carbon nanotubes (CNTs) or nanoparticles on Si wafers in a microwave plasma electron cyclotron resonance chemical vapor deposition (ECR-CVD) system with CH4 and/or H-2 as source gases. The magnetic catalyst materials, including Fe-Pt, Co-Pt, Nd2Fe14B, Fe and Fe-Ni, were first deposited on Si wafers by a physical vapor deposition (PVD) method, with subsequent plasma treatment for nanoparticle transformation. The main process parameters include catalyst materials, hydrogen plasma catalyst pretreatment and deposition temperature. For applications in magnetic media, the process has the following advantages: perpendicularly aligned CNTs or nanoparticles; tip-growth CNTs; well-distributed magnetic particles; detectable magnetic field in each particle; high tube number density (up to 134 Gtubes/inch(2) for Fe-assisted CNTs); favorable catalyst size; higher shape and induced anisotropy; and nanostructures that can be manipulated. The catalyst particle sizes of Fe, Nb2Fe14B and Fe-Pt (35-40 mn in diameter) are uniform and greater than but close to the critical optimum size or single domain size, which favor a higher coercive force. The greatest coercive force can reach 750 Oe for Fe-assisted CNTs at a deposition temperature of 715 degreesC, which is comparable with values reported in the literature. The coercive force difference between the vertical and horizontal directions can reach 300 Oe for Fe-assisted CNTs, and 355 Oe for Nb2Fe14B-assisted CNTs. (C) 2002 Elsevier Science B.V. All rights reserved.