Rapid Growth of Long, Vertically Aligned Carbon Nanotubes through Efficient Catalyst Optimization Using Metal Film Gradients

Pulsed laser deposited, orthogonally overlapping metal film gradients are introduced as a versatile method to optimize desired nanomaterial characteristics simultaneously as a function of catalyst composition and film thickness. Catalyst libraries generated by this method are applied here to study the growth of vertically aligned carbon nanotubes by chemical vapor deposition in acetylene from Mo/Fe/Al multilayers on Si. An Fe/Mo atomic ratio of 16:1 was discovered to be optimal for the rapid growth of nanotubes to long lengths, at rates exceeding 1 mm/hr.