The formation of new phase and chemical bonds in N-doped diamond films induced by swift heavy ion irradiation

In this paper, the formation of the new phase and chemical bonds in N-doped diamond films after swift heavy ion irradiations was studied. The original samples were diamond films grown on (111) oriented p-Si by CVD deposition. These samples were implanted with 100 keV N-ions at room temperature to 5 x 10(17), 1 x 10(18) and 5 x 10(18) N/cm(2), irradiated with 345 MeV Xe or 2.64 GeV U ions, and then analyzed by means of RBS, micro-FTIR, micro-Raman and XRD spectroscopy. The obtained results suggested that N-sp(2)C and N-sp(3)C bonds formed in all N-doped diamond films, CdropN bond exists in all 5 x 10(18) N/cm(2) doped samples but could not form in the 5 x 10(17) N/cm(2) doped samples. In the 1 x 10(18) N/cm(2) doped sample, CdropN bond could form only after swift heavy ion irradiation. Intense energy deposition from the incident swift heavy ions induces the increase of sp(3)/sp(2) bonding ratio and thus enhances the formation of N-sp(3)C bonds in the samples. Furthermore, the X-ray diffraction analysis indicated that there existed new phases, alpha- and beta-C3N4 in the N-doped diamond samples after irradiation by swift heavy ions. (C) 2003 Elsevier B.V. All rights reserved.