Diameter controlled synthesis of carbon nanotubes by CVD using steric-stabilized iron nanoparticle catalysts

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Carbon nanotubes (CNT) are the subject of intensive investigation due to their potential applications in nanoelectronics, biological sensors, high performance materials etc. CNTs can be synthesized using variety of techniques of which synthesis using chemical vapor deposition (CVD) typically involves growth in the presence of transition metal catalyst nanoparticles. The diameter of the CVD synthesized nanotubes strongly depends on the size of the catalyst nanoparticles employed for their growth. One of the challenges to realize diameter controlled growth of CNTs is to preserve the initial size of the nanoparticle catalyst during initial stages of nanotube growth. In this report we propose a simple strategy to prevent aggregation of nanoparticles during nanotube growth. Surface modified iron nanoparticle catalysts are used for the diameter controlled carbon nanotube forest growth at 650°C using chemical vapor deposition. Temperature induced aggregation of nanoparticles commonly observed when preformed nanoparticle catalysts are employed was successfully prevented by surface modification of nanoparticles with aminpropyltriethoxysilane (APS). APS formed a siliceous deposit around the nanoparticles that prevented the agglomeration of nanoparticles at the early stages of nanotube growth thus allowing synthesis of carbon nanotubes with sizes equal to the diameter of the catalyst particles.

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Journal: TechConnect Briefs
Volume: 1, Technical Proceedings of the 2006 NSTI Nanotechnology Conference and Trade Show, Volume 1
Published: May 7, 2006
Pages: 98 - 101
Industry sector: Advanced Materials & Manufacturing
Topic: Carbon Nano Structures & Devices
ISBN: 0-9767985-6-5