A method of making carbon nanotubes is provided, the method includes depositing a catalyst layer on a substrate, placing the substrate having the catalyst layer in a reaction furnace, heating the reaction furnace to a predetermined temperature, introducing a carbon source gas and a protective gas into the reaction furnace to grow a first carbon nanotube segment structure comprising a plurality of metallic carbon nanotube segments, and applying a pulsed electric field to grow a second carbon nanotube segment structure from the plurality of metallic carbon nanotube segments, where the pulsed electric field is a periodic electric field including a plurality of positive electric field pulses and a plurality of negative electric field pulses alternately arranged, and the second carbon nanotube segment structure includes a plurality of semiconducting carbon nanotube segments.