Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Effect of Substrate Morphology on Growth and Field Emission Properties of Carbon Nanotube Films | Nanoscale Res Lett 2008 3 205-212 DOI s11671-008-9138-0 NANO EXPRESS Effect of Substrate Morphology on Growth and Field Emission Properties of Carbon Nanotube Films Sanjay K. Srivastava V. D. Vankar Vikram Kumar V. N. Singh Received 13 March 2008 Accepted 3 June 2008 Published online 13 June 2008 to the authors 2008 Abstract Carbon 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 honeycomb 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 V m. The defective bamboo-structure structures of CNTs have been suggested for the enhanced emission performance of randomly oriented nanotube samples. Keywords Carbon nanotubes CNTs Bamboo-structured CNTs BS-CNTs Chemical vapor deposition CVD Transmission electron microscopy TEM Field emission S. K. Srivastava V. D. Vankar V. N. Singh Department of Physics Thin Film Laboratory Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India Present Address S. K. Srivastava El V. Kumar National Physical Laboratory Dr. . Krishnan Marg Pusa New Delhi 110012 India e-mail srivassk@ Introduction Carbon nanotubes CNTs 1 have attracted wide attention both in the research and
