Phase Transformation and Enhancing Electron Field Emission Properties in Microcrystalline Diamond Films Induced by Cu Ion Implantation and Rapid Annealing^*

Cu ion implantation and subsequent rapid annealing at 500°C in N₂ result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm² V⁻¹ S⁻¹ for microcrystalline diamond (MCD) films. Its electrical field emission behavior can be turned on at E₀ = 2.6 V/μm, attaining a current density of 19.5μA/cm² at an applied field of 3.5 V/μm. Field emission scanning electron microscopy combined with Raman and x-ray photoelectron microscopy reveal that the formation of Cu nanoparticles in MCD films can catalytically convert the less conducting disorder/a-C phases into graphitic phases and can provoke the formation of nanographite in the films, forming conduction channels for electron transportation.