Selective synthesis of metallic and semi-conducting single-walled carbon nanotube by floating catalyst chemical vapour deposition

Abstract

Selective synthesis of both metallic and semi-conducting single-walled carbon nanotubes (SWCNTs) has been performed using floating catalyst chemical vapour deposition (FC-CVD). It was observed that partial pressure of hydrogen determined the selectivity of SWCNTs being predominantly metallic at lower hydrogen concentration (20 vol%) and predominantly semiconducting at higher hydrogen concentration (80 vol%). The qualitative and quantitative analysis on type of SWCNTs was performed based on UV–vis-NIR, Raman spectra at different wavelengths and SWCNT-based field effect transistor device performance. Transmission electron microscopy was used to get diameter distribution of SWCNTs. Detailed analysis showed that the type of SWCNTs was decided at the nucleation stage that was governed by the collision frequency between hydrogen molecules and iron nanoparticles.