Cobalt–polypyrrole–cobalt nanowire field-effect transistors

Cobalt–polypyrrole(PPy)–cobalt nanowires were fabricated electrochemically in single-wire form inside anodic aluminum oxide templates. These wires were isolated by dissolving the template with chromic acid. Grown cobalt segments at both ends reveal a polycrystalline structure of a hexagonal-closest-packed structure and their [001] directions are 16° off the wire axis. By patterning a gate on one side of the wire, field-effect transistors (FETs) were produced. The measured output and transfer characteristics are as good as or better than film FETs of PPy. The gain of the wire FET could be controlled with successive electrochemical doping of the PPy segment.