Electron ballistic characteristic optimization in individual MWCNT by oxygen plasma treatment
Surface treatment and bonding oxygen species represent a practical method for strongly enhancing the ballistic characteristic of carbon nanotubes (CNTs) because the electrical properties strongly depend on the surface states. In this work, oxygen plasma was introduced onto the CNTs to remove the remaining defects, leading to a 44.8% improvement in the graphite-like sp2 bonding, which represents the graphite level of the CNTs. Moreover, oxygen species were bonded onto each individual CNT, as seen from the AES analysis. The conductive characteristics, such as resistivity, electron concentration, and electron mobility, for individual treated CNTs were optimized significantly under 20 s oxygen plasma treatment, giving values of 1.23 × 102 μΩ cm, 6.36 × 1018 cm−3, and 8002.23 cm2 V−1 s−1, respectively. Furthermore, we demonstrated an experimental approach to grow aligned CNTs by substrate clamping configurations without a bias voltage or porous substrate, which simplifies the complexity of procedure preparation and enhances the opportunity for extracting individually treated CNTs to investigate their specific conductive characteristics.