Purification of semiconducting carbon nanotubes

The purification of carbon nanotubes (CNTs) is done by selectively synthesizing pure semiconductor CNTs or separating metallic and semiconducting CNTs after nanotubes growth. Methane Plasma reaction mechanism is developed that selectively etches and eliminates metallic CNTs from a nanotube film without damaging semiconductor CNTs with a diameter of 1.4 nm. The solution-phase approach is applied to suspended nanotubes in solvents and electrical breakdown selectively removes metallic nanotubes on the substrates after fabricating electrode on CNTs. The studies have shown that the selective hydrocarbonation reaction between metallic carbon and a methane plasma obtains pure semiconductor CNTs with electrical properties similar to pristine materials. The gas-phase treatment is applied for the purification of wafer scales that fit into the plasma reaction chamber.