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: The Influences of H2 Plasma Pretreatment on the Growth of Vertically Aligned Carbon Nanotubes by Microwave Plasma Chemical Vapor Deposition | Nanoscale Res Lett 2008 3 230-235 DOI s11671-008-9141-5 NANO EXPRESS The Influences of H2 Plasma Pretreatment on the Growth of Vertically Aligned Carbon Nanotubes by Microwave Plasma Chemical Vapor Deposition Sheng-Rui Jian Yuan-Tsung Chen Chih-Feng Wang Hua-Chiang Wen Wei-Ming Chiu Chu-Shou Yang Received 2 April 2008 Accepted 12 June 2008 Published online 24 June 2008 to the authors 2008 Abstract The effects of H2 flow rate during plasma pretreatment on synthesizing the multiwalled carbon nanotubes MWCNTs by using the microwave plasma chemical vapor deposition are investigated in this study. A H2 and CH4 gas mixture with a 9 1 ratio was used as a precursor for the synthesis of MWCNT on Ni-coated TaN Si 100 substrates. The structure and composition of Ni catalyst nanoparticles were investigated using scanning electron microscopy SEM and transmission electron microscopy TEM . The present findings showed that denser Ni catalyst nanoparticles and more vertically aligned MWCNTs could be effectively achieved at higher flow rates. From Raman results we found that the intensity ratio of G and D bands d q decreases with an increasing flow rate. In addition TEM results suggest that H2 plasma pretreatment can effectively reduce the amorphous carbon and carbonaceous particles. As a result the pretreatment plays a crucial role in modifying the obtained MWCNTs structures. . Jian El . Chen . Wang Department of Materials Science and Engineering I-Shou University Syuecheng Rd. Dashu Township Kaohsiung 840 Taiwan ROC e-mail srjian@ . Wen Department of Electrophysics National Chiao Tung University Hsinchu 300 Taiwan ROC . Chiu Department of Chemical and Materials Engineering National Chin-Yi University of Technology Taichung 411 Taiwan ROC . Yang Graduate Program in Electro-Optical Engineering Tatung Universiy Taipei 10452 Taiwan ROC Keywords Multiwalled carbon nanotubes H2 pretreatment Raman spectroscopy Scanning electron .
