Patterned growth and field emission properties of ve

Vertically aligned carbon nanotubes were grown selectively on patterned Ni thin films by microwave plasma-enhanced chemical
vapor deposition and their field emission properties were investigated using a diode-structure. Ni thin films patterned with a form
of dot-arrays were prepared using a shadow mask having an array of holes. The nanotubes were found to be well-graphitized with
multiwalled structures. The measurements of field emission properties revealed that the carbon nanotube tips emitted high
current density at low macroscopic electric field. The FowlerNordheimŽFN.plot clearly showed two characteristic regions
where the current saturates at the high electric field region. It was found that the saturation behavior was caused by the
adsorbates-enhanced field emission mechanism. Eliminating the adsorbates resulted in no saturation behavior, increasing turn-on
field, decreasing current, and increasing field enhancement factor. Using ZnSCu,Al phosphor, very bright and uniform emission
patterns were obtained 微波等离子体增强化学气相沉积系统(MPECVD)