Microstructural Modifications of Diamond-Graphite Nanocomposites for High-Current Field Electron Sources

Abstract

The requirements for cathode materials for high-current field electron sources and problems of their creation have been formulated and justified. Using a nonequilibrium microwave plasma of the low-pressure ethanol vapors, the limits of regimes for forming the nanocomposite film coatings containing the diamond and graphite phases in different volume ratios have been established. The deposition temperature-dependent effect of self-organization of diamond nanocrystallites in the graphite and polymer-like carbon films on quartz and polykor substrates has been found. It is shown that, choosing a regime of the nonequilibrium condensation of diamond-graphite nanocomposites, one can reduce the field electron emission threshold from 15–17 to 4–6 V/μm and enhance the field-emission current density in a microsecond pulse over 100 A/cm².