Preparation and characterization of nanostructured film of graphitized diamond crystallites for field electron emission

Abstract

The details are given of the preparation technique that has been developed for depositing crystalline-nanodiamond particles on large-area silicon substrates, based on an dielectrophoresis process. A patented technique was adapted to prepare the substrate surface with high density of uniformly distributed nanoprotrusions that provide local field enhancement necessary for dielectrophoresis deposition. The nanodiamond crystallites were treated at elevated temperatures to have their surfaces graphitized. High-resolution transmission microscopy and electron diffraction techniques as well as micro Raman analysis were used to study the properties of the so-prepared nanostructured film. Stable field electron emission from these films with current density of >5 mA/cm2 may be regularly obtained at fields as low as ∼3 V/μm. The current–voltage characteristics and the corresponding Fowler–Nordheim plots, emission uniformity, and current stability were studied. The findings suggest that this type of film is a potential candidate as a large-area cold cathode. A model based on emission associated nanoscale graphite network and nanotriple junction is presented.