X-ray photoelectron spectroscopic study of plasma source nitrogen ion implantation in single crystal natural diamond

Plasma Source Ion Implantation (PSII) has been used to implant nitrogen in a single crystal natural diamond at room temperature with 5 keV energy. Nitrogen implanted diamond surface has been studied for the nitrogen state, its bonding with carbon and concentration at different depths by X-ray photoelectron spectroscopy (XPS). C1s peak and N1s peak binding energies indicate that after nitrogen implantation, sp2 hybridization takes place possibly due to partial graphitization of the surface and some of the homopolar C-C bonds are replaced by C-N bonds. C-N bond formation is seen up to the depth equivalent of 16 min argon ion etching. Further ion etching gives small nitrogen concentration values which are close to the determination limit of XPS technique. The results are compared with the earlier reports with some controversies regarding bonding and local nitrogen environment in carbon nitride and nitrogen implantation in diamond films.