Bonding and hardness in nonhydrogenated carbon films with moderate sp3 content

7 pages, 10 figures, 1 table.-- PACS: 68.60.Bs; 81.40.Pq; 68.35.Gy; 81.40.Np; 61.50.LtAmorphous carbon films with an sp3 content up to 25% and a negligible amount of hydrogen have been grown by evaporation of graphite with concurrent Ar + ion bombardment. The sp3 content is maximized for Ar + energies between 200 and 300 eV following a subplantation mechanism. Higher ion energies deteriorate the film due to sputtering and heating processes. The hardness of the films increases in the optimal assisting range from 8 to 18 GPa, and is explained by crosslinking of graphitic planes through sp3 connecting sites.This work has been partially financed by the Spanish CICYT under Project Nos. MAT96-0529 and PB97-1224, CAM Project No. AE 00140/94, NATO Project No. CRG-971539, and the US Department of Energy through Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48. The work was performed at the Stanford Synchrotron Radiation Laboratory, which is supported by the DOE, Office of Basic Energy Science. A grant from the F.P.U. program of the Spanish M.E.C. is also appreciated.Peer reviewe

Bonding and hardness in nonhydrogenated carbon films with moderate sp(3) content

Amorphous carbon films with an s p{sup 3} content up to 25% and a negligible amount of hydrogen have been grown by evaporation of graphite and concurrent Ar{sup +} ion bombardment. The s p{sup 3} content is maximized for Ar{sup +} energies between 200 and 300 eV following a subplantation mechanism. Higher ion energies deteriorate the film due to sputtering and heating processes. The hardness of the films increases in the optimal assisting range from 8 to 18 GPa, and is explained by the crosslinking of graphitic planes through s p {sup 3} connecting site