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Synthesis of TiO2 Nanowires by Metallorganic Chemical Vapor Deposition

유기금속 화학기상증착법을 이용한 TiO2 나노선 제조

  • Heo, Hun-Hoe (Department of Materials Science & Engineering, Chungnam National University) ;
  • Nguyen, Thi Quynh Hoa (Department of Materials Science & Engineering, Chungnam National University) ;
  • Lim, Jae-Kyun (Department of Materials Science & Engineering, Chungnam National University) ;
  • Kim, Gil-Moo (Department of Materials Science & Engineering, Chungnam National University) ;
  • Kim, Eui-Tae (Department of Materials Science & Engineering, Chungnam National University)
  • 허훈회 (충남대학교 공과대학 재료공학과) ;
  • 웬티깅화 (충남대학교 공과대학 재료공학과) ;
  • 임재균 (충남대학교 공과대학 재료공학과) ;
  • 김길무 (충남대학교 공과대학 재료공학과) ;
  • 김의태 (충남대학교 공과대학 재료공학과)
  • Received : 2010.10.22
  • Accepted : 2010.11.17
  • Published : 2010.12.27

Abstract

$TiO_2$ nanowires were self-catalytically synthesized on bare Si(100) substrates using metallorganic chemical vapor deposition. The nanowire formation was critically affected by growth temperature. The $TiO_2$ nanowires were grown at a high density on Si(100) at $510^{\circ}C$, which is near the complete decomposition temperature ($527^{\circ}C$) of the Ti precursor $(Ti(O-iPr)_2(dpm)_2)$. At $470^{\circ}C$, only very thin (< $0.1{\mu}m$) $TiO_2$ film was formed because the Ti precursor was not completely decomposed. When growth temperature was increased to $550^{\circ}C$ and $670^{\circ}C$, the nanowire formation was also significantly suppressed. A vaporsolid (V-S) growth mechanism excluding a liquid phase appeared to control the nanowire formation. The $TiO_2$ nanowire growth seemed to be activated by carbon, which was supplied by decomposition of the Ti precursor. The $TiO_2$ nanowire density was increased with increased growth pressure in the range of 1.2 to 10 torr. In addition, the nanowire formation was enhanced by using Au and Pt catalysts, which seem to act as catalysts for oxidation. The nanowires consisted of well-aligned ~20-30 nm size rutile and anatase nanocrystallines. This MOCVD synthesis technique is unique and efficient to self-catalytically grow $TiO_2$ nanowires, which hold significant promise for various photocatalysis and solar cell applications.

Keywords

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