Sulfur impregnation of multi-walled carbon nanotubes via SF6/NH3plasma exposure

Abstract

SEM-EDX map of SF6/NH3 plasma-treated multi-walled carbon nanotubes on substrate. Green, yellow and red correspond to silicon, carbon and sulfur signals, respectively. Plasma treatments are established methods to functionalise carbon nanotubes (CNTs) and modify their surface structure. This paper presents a mild glow-discharge plasma treatment of aligned arrays of multi-walled carbon nanotubes employing sulfur hexafluoride (SF6), ammonia (NH3), and their mixtures as process gases. For the latter, sulfur was detected at the tip and sidewalls of the nanotubes via energy-dispersive X-ray spectroscopy, while electron microscopy served as method to verify the structural integrity of the CNTs after the plasma treatment. This approach provides the basis for an easy and quick alternative to existing sulfur functionalisation methods of MWCNTs. Furthermore, the proposed method can conveniently be applied to carbon nanotube arrays on substrate while preserving their structure and alignment.