Tuning of the Structure and Electrical Properties of MWCNTs by Dielectric Barrier Discharge (DBD) Plasma Treatment

Abstract

This paper aims to investigate the effect of oxygen and nitrogen dielectric barrier discharge (DBD) plasma treatment at different voltages on the structure and electrical properties of metallic multi-walled carbon nanotubes (MWCNTs). The surface structure and electrical properties changes before and after treatments were studied by using Transmission Electron Microscopy (TEM), Fourier Transform Infra-Red (FTIR) and hall effect measurement. The degree of defect was observed increased along with increasing applied voltage of plasma, obviously demonstrated from TEM measurements.  For the MWCNTs-O₂, the FTIR exhibited formation of oxygen-containing groups such as C=O and COOH on the MWCNTs and the addition of N-H vibration bending for the MWCNTs-N₂. The highest hall mobility (172.9 cm²/Vs) was achieved when MWCNTs treated with nitrogen at 12kV which is slightly higher than mobility of SWCNT thin film (150 cm²/Vs) reported by previous researcher. This showed that at higher intensity, the nitrogen-containing group can modify the metallic MWCNTs to semiconducting behavior.