Direct measurement of charge transport through helical poly(ethyl propiolate) nanorodswired into gaps in single walled carbon nanotubes

Abstract

We report the direct measurement of electrical transport through rod-like polymer molecules,of poly(ethyl propiolate) (PEP), utilizing single walled carbon nanotubes (SWNTs) aselectrodes. The electrical properties of the devices were measured (i) before cutting aSWNT, (ii) when a SWNT was cut and (iii) after PEP deposition into the nanoscale gap ina cut SWNT. The gate-dependent electrical properties showed a reduction in current fromIon = 2.4 × 10−7 A for SWNTdevices to Ion = 3.6 × 10−9 A for PEP bridge devices, both with the ON/OFF ratio of104. Similarly, metallic SWNT devices showed a reduction in current from a few hundreds ofµA fora SWNT device to a few nA for a PEP–SWNT structure. The current density of a single PEP moleculeis 105–106 A cm−2, which is relatively high, indicating that the PEP molecule can carry significant current.Use of SWNT electrodes was seen to be an effective method of contacting PEP nanorods tofacilitate electrical measurements.