Imaging conduction pathways in carbon nanotube network transistors by voltage-contrastscanning electron microscopy

Abstract

The performance of field-effect transistors based on single-walled carbon nanotube(SWCNT) networks depends on the electrical percolation of semiconducting and metallicnanotube pathways within the network. We present voltage-contrast scanningelectron microscopy (VC-SEM) as a new tool for imaging percolation in a SWCNTnetwork with nano-scale resolution. Under external bias, the secondary-electroncontrast of SWCNTs depends on their conductivity, and therefore it is possibleto image the preferred conduction pathways within a network by following thecontrast evolution under bias in a scanning electron microscope. The experimentalVC-SEM results are correlated to percolation models of SWCNT-bundle networks.