Directed Growth and Electrical- Transport Properties of Carbon Nanotube Architectures on Indium Tin Oxide Films on Silicon-Based Substrates

Growing aligned carbon nanotubes (CNTs) on electrically conducting and/or optically transparent materials is potentially useful for accessing CNT properties through electrical and optical stimuli. Here, we report a new approach to growing aligned bundles of multiwalled CNTs on a porous back contact...

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Bibliographic Details
Published in:Advanced functional materials 2005-12, Vol.15 (12), p.1922-1926
Main Authors: Agrawal, S., Frederick, M. J., Lupo, F., Victor, P., Nalamasu, O., Ramanath, G.
Format: Article
Language:English
Subjects:
Carbon nanotubes
Charge transport
Conductivity
Conductivity, electrical
electrical
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Summary:Growing aligned carbon nanotubes (CNTs) on electrically conducting and/or optically transparent materials is potentially useful for accessing CNT properties through electrical and optical stimuli. Here, we report a new approach to growing aligned bundles of multiwalled CNTs on a porous back contact of optically transparent and electrically conducting indium tin oxide (ITO) films on silicon and silica substrates without the use of a predeposited catalyst. CNTs grow from a xylene/ferrocene mixture, which traverses through the pores in the thin ITO film, and decomposes on an interfacial silica layer formed via the reaction between ITO and the Si substrate. The CNTs inherit the topography of the silica substrate, enabling back‐contact formation for CNTs grown in any predetermined orientation. These features can be harnessed to form CNT contacts with other substrate materials which, upon reduction by Si, results in a conducting interfacial layer. The ITO‐contacted CNTs exhibit thermally activated ohmic behavior across a 100 ± 10 meV barrier at electric fields below ∼ 100 V cm–1 due to carrier transport through the outermost shells of the CNTs. At higher electric fields, we observe superlinear behavior due to carrier tunneling and transport through the inner graphene shells. Our findings open up new possibilities for integrating CNTs with Si‐based device technologies. Carbon‐nanotube growth on optically transparent and electrically conducting substrates is attractive for realizing new types of optical and electronic devices. Here, selective directional growth of aligned nanotubes is demonstrated on indium‐tin‐oxide‐coated silicon and silica substrates (see Figure). Electrical tests show superlinear current–voltage behavior, attributed to carrier transport via multiple graphene shells of the nanotubes.
ISSN:1616-301X
1616-3028
DOI:10.1002/adfm.200500165