Synthesis and Properties of Electrically Conductive/Nitrogen Grain Boundaries Incorporated Ultrananocrystalline Diamond (N-UNCD) Thin Films Grown by Microwave Plasma Chemical Vapor Deposition (MPCVD)

Research and development have been performed to investigate the effect of total pressure and microwave power on the electrical conductivity of nitrogen (N) atoms' grain boundaries incorporated ultrananocrystalline diamond (N-UNCD) films grown by microwave plasma chemical vapor deposition (MPCVD). Insertion of N atoms into the UNCD film's grain boundaries induces N atoms chemical reaction with C-atoms dangling bonds, resulting in release of electrons, which induce electrical conductivity. Four-point probe electrical measurements show that the highest electrically conductive N-UNCD films, produced until now, exhibit electrical resistivity of similar to 1 Ohm.cm, which is orders of magnitude lower than the >= 106 Ohm.cm for undoped ultrananocrystalline diamond (UNCD) films. X-ray diffraction analysis and Raman spectroscopy revealed that the growth of the N-UNCD films by MPCVD do not produce graphite phase but only crystalline nanodiamond grains. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of nitrogen (N) in the N-UNCD films and the high conductivity (no electrical charging is observed during XPS analysis) shown in electrical measurements.

Automated summary

The research investigates the impact of total pressure and microwave power on the electrical conductivity of N-UNCD films. Results show that inserting nitrogen atoms into the grain boundaries significantly enhances the electrical conductivity. Through X-ray diffraction and Raman spectroscopy, it was found that the N-UNCD films produced do not contain graphite phase but only crystalline nanodiamond grains. XPS analysis confirmed the presence of nitrogen and high conductivity in the N-UNCD films.