Effect of DC Bias on Microwave Plasma Enhanced Chemical Vapor Deposition Synthesis of Single-Walled Carbon Nanotubes

Abstract

The physical properties of carbon nanotubes (CNTs) make them outstanding candidates for introduction into technologies ranging from high resolution flat panel displays to nanoscale transistors. Integration of carbon nanotubes into devices, however, requires precise control over the manufacturing processes used during their synthesis. To meet the specific requirements of a given application, alignment, diameter, length and chirality of carbon nanotubes must be strictly addressed. This work demonstrates the controlled synthesis of single-walled carbon nanotubes (SWCNTs) with low amount of undesired carbonaceous species using plasma enhanced chemical vapor deposition (PECVD). This report elucidates the role of DC bias applied to the growth substrate during synthesis, including the field-enhanced alignment of SWCNTs, selectivity in the diameter distribution and selectivity of semiconducting versus metallic nanotubes. Carbon nanotubes are characterized using Raman spectroscopy and electron microscopy.