Systematic investigation of experimental parameters on nitrogen incorporation into carbon nanotube forests

Nitrogen doping carbon nanotubes can enhance their beneficial physical and chemical properties, rendering them more desirable for various applications, e.g., in electronics. In this study, we used catalytic chemical vapor deposition to synthesize carbon na-no-tube forests on different substrates. The samples were prepared in the presence of compounds containing nitrogen (ammonia, acetonitrile, tripropylamine, and their mixture with acetone) that were introduced into the reactor by bubbling or injection. Of the two different nitrogen introduction methods, the direct injection of a liquid nitrogen precursor promoted the synthesis of bamboo-structured carbon nanotube forests more efficiently. It was found in the injection experiments that the amount of precursor affected the extent of nitrogen incorporation. The presence of various nitrogen species in CNTs was also identified, and the manner in which temperature and the presence of hydrogen both influence nitrogen incorporation into the carbon na-no-tubes was observed