Effectively Improved Field Emission Properties of Multiwalled Carbon Nanotubes/Graphenes Composite Field Emitter by Covering on the Si Pyramidal Structure

The composite nanostructure emitter of multiwalled carbon nanotubes and graphenes was deposited on pyramidal silicon substrate by the simple larger scale electrophoretic deposition process. The field emission (FE) properties of the composite/pyramidal Si device were greatly improved compared with that of the composite/plain Si. The low turn-ON electric field, the low threshold electric field, and the larger enhancement factor were obtained using the pyramidal structure. The better FE performances of the composite/pyramidal Si were a combined effect of the field enhancement from the composite emitter and the pyramidal Si structure. The numerical simulation of the electric field distribution on composite/pyramidal cathode was used to illuminate the improved FE properties by using the pyramidal substrate. These studies indicate that constructing composite/pyramidal structure is one of the efficient ways to improve the FE properties.