Deposition and Characterization of Diamond Nanowires in N₂-Rich N₂/CH₄/H₂ Atmosphere Reactor

The coatings of diamond nanowires were grown by microwave plasma chemical vapor deposition in N₂-rich N₂/CH₄/H₂ atmosphere.The impact of the N₂ concentration on the diamond nanowire length and surface morphology of the films was investigated with scanning electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy.The results show that the N₂ concentration had a major impact.For example, grown at N₂-85%, the coating comprised diamond nanowires with an average length of 2.5 μm and the crystalline grains of 8 nm.As the N₂-concentration increased, the N-content in the coating increased, peaking to N-2.68% at N₂-95%.A reduction of the grain-size resulted in increases of both grain boundary density and C=C bonds, and a decrease of the C-C bonds.The lowest FWHM of XPS spectrum of C-C bonds, formed at N₂-content of 85%, was 1.16 e V.Possible mechanisms were also tentatively discussed.