tailieunhanh - Báo cáo hóa học: " Effect of Purity and Substrate on Field Emission Properties of Multi-walled Carbon Nanotubes"

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 Purity and Substrate on Field Emission Properties of Multi-walled Carbon Nanotubes | Nanoscale Res Lett 2007 2 331-336 DOI S11671-007-9067-3 NANO EXPRESS Effect of Purity and Substrate on Field Emission Properties of Multi-walled Carbon Nanotubes R. B. Rakhi K. Sethupathi S. Ramaprabhu Received 15 March 2007 Accepted 24 May 2007 Published online 21 June 2007 to the authors 2007 Abstract Multi-walled carbon nanotubes MWNT have been synthesized by chemical vapour decomposition CVD of acetylene over Rare Earth RE based AB2 DyNi2 alloy hydride catalyst. The as-grown carbon nanotubes were purified by acid and heat treatments and characterized using powder X-ray diffraction Scanning Electron Microscopy Transmission Electron Microscopy Thermo Gravimetric Analysis and Raman Spectroscopy. Fully carbon based field emitters have been fabricated by spin coating a solutions of both as-grown and purified MWNT and dichloro ethane DCE over carbon paper with and without graphitized layer. The use of graphitized carbon paper as substrate opens several new possibilities for carbon nanotube CNT field emitters as the presence of the graphitic layer provides strong adhesion between the nanotubes and carbon paper and reduces contact resistance. The field emission characteristics have been studied using an indigenously fabricated set up and the results are discussed. CNT field emitter prepared by spin coating of the purified MWNT-DCE solution over graphitized carbon paper shows excellent emission properties with a fairly stable emission current over a period of 4 h. Analysis of the field emission characteristics based on the Fowler-Nordheim FN theory reveals current saturation effects at high applied fields for all the samples. R. B. Rakhi S. Ramaprabhu El Alternative Energy Technology Laboratory Department of Physics Indian Institute of Technology Madras Chennai 600036 India e-mail ramp@ R. B. Rakhi K. Sethupathi Low Temperature Laboratory Department of Physics Indian Institute of Technology Madras Chennai 600036 India Keywords Multi-walled carbon .