Fabrication and electrical conductivity of suspended carbon nanofiber arrays

Abstract

We demonstrate a simple, efficient and novel self-assembly based method to fabricate arrays of suspended polymeric nanofibers of polyacrylonitrile and SU-8 negative photoresist by electrospinning on micro-fabricated posts of resorcinol-formaldehyde (RF) gel. The suspended electrospun nanofibers together with the RF gel posts were subsequently pyrolyzed in an inert atmosphere to yield large area monolithic structures of suspended glassy carbon nanofibers (CNF) integrated on RF gel derived carbon posts. The electrospun nanofibers self-assemble to connect the posts owing to a stronger electric field on their tips, obviating the need for positioning and integration of carbon nanowires with the underlying microstructures and paving the way for fabricating novel carbon based micro and nano-scale devices. The fabrication technique also allowed measurements of electrical conductivity of a single suspended CNF between carbon electrodes using I-V characteristics and comparison of the carbon nanowire conductivities for the CNF derived from different polymer precursors.