LAUSR

Abstract In this paper, nitrogen doped diamond–like carbon (N–DLC) films are successfully prepared by helicon wave plasma (HWP) on silicon substrates in Ar/CH4/N2 gas mixtures at different DC negative bias voltages (–VDC). The surface morphology, structure and properties of N–DLC films have been studied by SEM, AFM, Raman and XPS. The deposition rate of the film decreases with increasing –VDC from 0 V to –50 V. The results of Raman spectra show that ID/IG decreases from 1.22 to 1.10 with increasing –VDC. The elemental surface composition of the N–DLC films has been analyzed by XPS. The results show that the N content and sp3/sp2 ratio of the N–DLC films increase with the increase of –VDC. Young's modulus values measured by AFM in SPM mode also show the expected increase with increasing –VDC. Moreover, the N–DLC electrode has been used to study the electrochemical reversibility.