Optimization of methane cold wall chemical vapor deposition for the production of single walled carbon nanotubes and devices

摘要

Carbon nanotubes are synthesized by cold wall chemical vapor deposition (CVD) using methane as the carbon source and iron thin 131m catalyst. The yield of thin nanotubes as determined by scanning electron microscopy (SEM) is strongly dependent on the precise CVD process and the preparation of the substrate. The effects of pressure (5-80 kPa), temperature (700-950 deg C), substrate conditioning (sir preheat) and metallization (Fe, Al, Mo) on thin nanotube yield are reported. High yields of thin nanotubes are obtained under optimum conditions. These thin nanotubes are candidates to be single walled carbon nanotubes (SWNTs) and Raman spectroscopy, photoluminescence spectroscopy and electrical transport provide evidence that, at least at optimum conditions, many, and perhaps all of the third nanotubes are single walled. Single nanotube field effect transistors are fabricated and factors affecting device yield are reported. Optimum single nanotube device yield does not necessarily coincide with the optimum nanotube yield.