Growth and field electron emission of vertically aligned multiwalled carbon nanotubes

Vertically well-aligned carbon nanotubes (CNTs) are grown on a Ni deposited silicon oxide substrate at 950°C by thermal chemical vapor deposition using C2H2. The uniformly grown CNTs with a diameter of about 60 nm have unique beak-like tips without any encapsulated Ni particles inside and exhibit high field emission current density, e.g. 2.9 mA/cm2 at 3.7 V/μm, following a Fowler–Nordheim behavior.