Synthesis of randomly oriented carbon nanotubes on SiO2 substrates by thermal chemical vapor deposition toward field electron emitters

Abstract Randomly oriented carbon nanotubes (CNTs) were synthesized directly on SiO 2 substrates by thermal chemical vapor deposition (CVD) with C 2 H 4 gas as a carbon source. To control the diameters of the carbon nanotubes, Fe–Ni thin films with different thickness from 80 to 320 nm were deposited as catalysts on SiO 2 substrates by magnetron sputtering. The diameter of the resultant carbon nanotubes was dependent on the size of the catalyst particles. Moreover, a small catalyst particle permitted carbon nanotube growth. The resultant randomly oriented carbon nanotubes exhibited good field emission properties.