Chemical gating and photoconductivity of CF4 plasma-functionalized single-walled carbon nanotubes with adsorbed butylamine

In this work we have developed a method to covalently attach butylamine molecules to the sidewall of single-walled carbon nanotubes sSWNTsd starting from fluorinated SWNTs sF-SWNTsd obtained by CF4 plasma treatment at room temperature. Scanning tunneling microscopy images demonstrate that after the sidewall fluorination of SWNTs some bundles with a lower number of single tubes are present. The subsequent amine functionalization of the tubes has been demonstrated by infrared spectroscopy and thermogravimetric measurements. The chemical adsorption of butylamine molecules on F-SWNTs has been also investigated by electrical transport measurements in thin-film transistor geometry. The electrical conductance of SWNTs decreases after adsorption of butylamine. The amine groups in the molecule are electron donating and the observed photoconductivity of amino-functionalized F-SWNTs is presumably due to the injection of electrons from amine groups to SWNTs.