Synthesis of multi branched carbon nanotubes in porous anodic aluminum oxide template

Abstract

Porous anodic aluminum oxide (AAO) templates, obtained by anodization of aluminum plates at relatively high voltages, were used for growing multi-branched carbon nanotubes which copy the three-dimensional branching structure of the nanochannels in the template. The formation of these branched nanochannels is characteristic of AAO templates grown at 60 V. When AAO templates are grown at 40 V or lower, straight channels and carbon nanotubes (CNTs) are obtained. At 60 V some ramifications grow for a short time from the main axis of the pore, following the direction of film growth. The repetition of this process along the main channel induces a kind of three-dimensional pore structure which is copied when the CNTs are grown in the template. In this way it is possible to get bundles of branched carbon nanotubes grown into AAO templates with a tailored ramified channel structure.