Production of vertical arrays of small diameter single-walled carbon nanotubes

A method for producing at least one vertical small diameter single walled nanotube, said method comprising the step of:

• placing at least one catalyst on a nanotube growth substrate surface, wherein said catalyst is placed in a pattern on said substrate;
• heating a gas mixture to form an activated gas, wherein said gas mixture is activated prior to introduction to said reaction chamber;
• inserting the substrate into a reaction chamber with the activated gas comprising atomic hydrogen and a carbon containing species, wherein said substrate is kept at room temperature prior to insertion into the reaction chamber;
• and
• heating the substrate and said activated gas in the reaction chamber, wherein at least one vertical small diameter nanotube is produced at said at least one catalyst on said nanotube growth substrate, and said at least one vertical small diameter nanotube has a diameter less than 3 nm.