Carbon nanotubes(CNTs)have been synthesized from Ar-CH_4 mixtures using rf-plasma enhanced chemical vapor deposition(rf-PECVD)at 500oC.Reduction gases such as H_2 and NH_3 were found unnecessary for carbon nanotube fo...Carbon nanotubes(CNTs)have been synthesized from Ar-CH_4 mixtures using rf-plasma enhanced chemical vapor deposition(rf-PECVD)at 500oC.Reduction gases such as H_2 and NH_3 were found unnecessary for carbon nanotube formation compared to thermal CVD.The relationship between the growth of CNTs and the plasma condition in PECVD has been investigated by in situ self bias measurement.Plasma conditions were controlled by changing the interelectrode distance,rf power and the applied substrate negative bias.By increasing the interelectrode distance and rf power,the spatial density of CNTs was on a rise as a result of the increase in ions density and self bias.As the applied substrate negative bias increased,the spatial density of CNTs decreased possibly due to the positive ions over bombarding effect.展开更多
基金financial support by the National Natural Science Foundation of China(grant No:10675070.50701026)the National Basic Research Program of China(973 program,2007CB936601)
文摘Carbon nanotubes(CNTs)have been synthesized from Ar-CH_4 mixtures using rf-plasma enhanced chemical vapor deposition(rf-PECVD)at 500oC.Reduction gases such as H_2 and NH_3 were found unnecessary for carbon nanotube formation compared to thermal CVD.The relationship between the growth of CNTs and the plasma condition in PECVD has been investigated by in situ self bias measurement.Plasma conditions were controlled by changing the interelectrode distance,rf power and the applied substrate negative bias.By increasing the interelectrode distance and rf power,the spatial density of CNTs was on a rise as a result of the increase in ions density and self bias.As the applied substrate negative bias increased,the spatial density of CNTs decreased possibly due to the positive ions over bombarding effect.
