Electron-emission properties of titanium carbide-coated carbon nanotubes grown on a nano-sized tungsten tip

Thin films (< 30 nm) of titanium carbide (TiC) are coated on carbon nanotubes (CNTs), directly grown on nano-sized (~ 500 nm in diameter) conical-type tungsten (W) tips, by employing an inductively coupled plasma chemical vapor deposition (ICP-CVD) technique. Modifications to structural properties (such as length to diameter ratio, crystal quality, and growth behavior) of CNTs due to TiC-coating are monitored using high-resolution TEM, field-emission SEM, and Raman spectroscopy. The driving voltage required to obtain the same level of emission current in CNTs-emitter is significantly reduced by TiC-coating. It is also noted that the degradation of emission current due to prolonged operation (up to 30 h) is remarkably suppressed by TiC-coating.