Polythiophene mesowires: synthesis by template wetting and local electrical characterisation of single wires

Abstract

We report on the synthesis of semiconducting mesowires from regioregular poly(3-hexylthiophene) via melt injection into a porous alumina template. Following liberation from the template, mesowires with diameters ∼450 nm and average lengths of 10 µm were obtained. For two-terminal electrical contacting of individual mesowires on insulating substrates, the drain electrode was formed by shadow masking and metal evaporation, and a conducting probe atomic force microscope tip was employed as the source electrode. This approach enabled combined topographic imaging and spatially resolved electrical characterisation of individual mesowires, allowing the intrinsic mesowire resistivity (700 ± 300 Ω m) as well as the contact resistance (10 ± 6 GΩ) to be estimated. Fitting the measured data to a thermionic emission–diffusion model yielded a hole mobility ∼2 × 10−5 cm2 V−1 s−1 and a metal–polymer interface barrier height ∼0.1 eV.