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Effect of Substrate Morphology on Growth and Field Emission Properties of Carbon Nanotube Films

Author(s): Srivastava Sanjay | Vankar VD | Kumar Vikram | Singh VN

Journal: Nanoscale Research Letters
ISSN 1931-7573

Volume: 3;
Issue: 6;
Start page: 205;
Date: 2008;
Original page

Keywords: Carbon nanotubes (CNTs) | Bamboo-structured CNTs (BS-CNTs) | Chemical vapor deposition (CVD) | Transmission electron microscopy (TEM) | Field emission

AbstractCarbon nanotube (CNT) films were grown by microwave plasma-enhanced chemical vapor deposition process on four types of Si substrates: (i) mirror polished, (ii) catalyst patterned, (iii) mechanically polished having pits of varying size and shape, and (iv) electrochemically etched. Iron thin film was used as catalytic material and acetylene and ammonia as the precursors. Morphological and structural characteristics of the films were investigated by scanning and transmission electron microscopes, respectively. CNT films of different morphology such as vertically aligned, randomly oriented flowers, or honey-comb like, depending on the morphology of the Si substrates, were obtained. CNTs had sharp tip and bamboo-like internal structure irrespective of growth morphology of the films. Comparative field emission measurements showed that patterned CNT films and that with randomly oriented morphology had superior emission characteristics with threshold field as low as ~2.0 V/μm. The defective (bamboo-structure) structures of CNTs have been suggested for the enhanced emission performance of randomly oriented nanotube samples.
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