Photoemission spectroscopic study of nitrogen-incorporated nanocrystalline diamond films

Abstract

The variation of composition and chemical bonding structures of the nanocrystalline diamond (ND) films induced by nitrogen incorporation in CH4(10%)∕H2∕N2 plasmas was investigated by x-ray photoelectron spectroscopy. The sp2∕sp3 phase ratio of hybridized carbon bonds in ND films was shown to depend strongly on the nitrogen concentration in plasma, coinciding with Raman observations. The depth profile analysis, however, revealed only about 1at.% of nitrogen in all samples, suggesting that the variation of conductivity of ND films is mainly associated with the development of highly ordered graphitic sp2 phase induced by the nitrogen incorporation.