Published online by Cambridge University Press: 09 January 2017
We have demonstrated the high yield and highly single wall selective synthesis of carbon nanotube forest grown using a MgO single crystal as a catalyst underlayer without any surface treatment. Such efficiency has not been previously reported using this underlayer system. Our investigation revealed that the growth ambient which contained no hydrogen but small amounts of water is essential for such efficiency. Evaluation of the growth kinetics by in-situ height monitoring revealed that the 350 μm tall forest with 65% single wall selectivity possessed a catalyst lifetime of about 5 minutes. Investigation by AFM, and XPS depth profiling revealed that this longer lifetime compared with as-deposited MgO can be attributed to the stability of the catalyst particle array with small size and high number density on MgO single crystal substrate. Shorter growth lifetime, when compared to the alumina underlayer system, resulted from an instability in the catalyst nanoparticle size and composition.