It was found that very high (up to 20vol%) N concentrations in ethanol/H gas mixtures did not impair diamond quality, as determined by using Raman spectroscopy. The N additions also increased the diamond growth-rate. It was observed that, after a second heating cycle in air at temperatures of between 300 and 673K, the resistance versus temperature curves of as-grown films indicated a bulk semiconducting behavior. Stabilization was due to oxidation of the as-grown hydrogenated surface. The electrical ionization energy was found to range from 1.62 to 1.90eV, for films produced with 0 to 20vol%N in the feed. The room temperature photoluminescence spectra of films which were produced at low N concentrations suggested that the electrical ionization energy resulted from pure electronic transitions in the N-vacancy neutral defects. In samples which were produced with N concentrations ranging from 15 to 20vol%, the electrical ionization energy could be attributed to so-called vibronic transitions and charged N-vacancy defects.

Nitrogen-Doped Diamond Films. V.Baranauskas, B.B.Li, A.Peterlevitz, M.C.Tosin, S.F.Durrant: Journal of Applied Physics, 1999, 85[10], 7455-8