Controllable fabrication of aligned carbon nanotubes by pulsed plasma: selective positioning and electrical transport phenomena

Selective growth of aligned carbon nanotubes (CNTs) at low temperature by pulsed plasma on Si₃N₄/Si substrates patterned by metallic platinum has been demonstrated. Field emission and atomic force microscopy (AFM) have shown that platinum does not support CNT growth, so that nanotubes can selectively grow on substrates patterned by platinum. This feasible fabrication method has been used to measure the electrical resistivity of as-aligned CNT film perpendicular to the tube axis without a complex postsynthesis manipulation. The prepared samples show a monotonic decrease in the resistivity with increasing temperature. We propose that the transport is governed by the formation of crossed junctions of nanotubes in the mat.