Room temperature synthesis of carbon nanofibers containing nitrogen by plasma-enhanced chemical vapor deposition

Abstract

This letter reports low-pressure, room-temperature growth of carbon nanofibers containing nitrogen by plasma chemical vapor deposition arrangement. By alternating pure acetylene plasma and afterglow pure nitrogen high dense plasma, a fine control of the fibers growth kinetic is obtained. This layer-by-layer deposition technique takes advantage of nitrogen chemical etching effects during the growth of nitrogen-doped carbon nanofibers.

Growth of carbon nanotubes at temperatures compatible with integrated circuit technologies

“…Progress has been reported recently in the lowering of the synthesis temperature, with reports of growth obtained using plasma-enhanced chemical vapour deposition (PECVD) [4][5][6][7] . However, in many cases demonstrating low temperature growth, the large area reproducibility and/or the quality of the nanotubes are not fully reported, or the growth results in carbon nanofibres (instead of nanotubes) [4][5][6][7] , with many internal material defects which affect their use as interconnects, requiring further annealing or opening up of inner-layer conduction channels via mechanical polishing 8,9 .…”

“…However, in many cases demonstrating low temperature growth, the large area reproducibility and/or the quality of the nanotubes are not fully reported, or the growth results in carbon nanofibres (instead of nanotubes) [4][5][6][7] , with many internal material defects which affect their use as interconnects, requiring further annealing or opening up of inner-layer conduction channels via mechanical polishing 8,9 . There has been a singular reporting of growth of SWNTs at low temperatures (below 400°C) 10 , non-uniform and over small areas, whilst follow-up attempts used temperatures in the region of 600°C 11 .…”

Influence of Fe/Cr on nitrogen doped carbon nanotube growth

“…Nanotube growth then occurred using an ECR-PECVD plasma in a mixture of acetylene/ammonia (1:2) with a grid bias of +200 V. Previous plasma characterization has shown strong correlation between the grid potential and the plasma potential [4]. Growth time was either one or two hours; all other experimental parameters were kept fixed.…”

“…ECR-PECVD is a versatile technique for growing and analyising CNTs, since there are many parameters such as gas feedstock and pressure, growth time, and plasma voltage that can be precisely controlled [1][2][3]. In addition there is the possibility for many in situ spectroscopic techniques allowing compositional analysis of the plasma.…”

“…In addition there is the possibility for many in situ spectroscopic techniques allowing compositional analysis of the plasma. Finally the combination of efficient ECR which gives high density plasmas and the control of the ion flux on the suba e-mail: chris.ewels@cnrs-imn.fr strate by dc grid biasing means that tubes can be grown at relatively low temperatures and mainly perpendicular to the substrate [2], encouraging growth far from thermal equilibrium. Moreover, this plasma process can potentially produce structures not attainable through higher temperature growth techniques or chemical vapour deposition (CVD).…”