Structuring carbon forms by energetic species: Amorphous, nano tubes and crystalline

Full Text: Energetic species in different. forms play a major role in current thin film technology. The evolution of such films via energetic particle bombardment is a shallow implantation (sub plantation) process. The stopping of the energetic species A the bombarded target advances through three stages: (i) collisional stage in which the species are stopped by the target via atomic displacements, ionization and phonon excitations, ii) the thermal relaxation stage i) which the excess energy is dissipated in the target; iii) the long term relaxation stage in which long term processes (diffusion, chemical reactions) take place. The final evolution of the structure is determined by the equilibrium between subsurface trapping at the final site and detrapping processes. Carbon is an excellent model system to study the structuring of materials by energetic species due to the host of possible configurations it forms. By properly altering the energy and temperature it is possible to form: (i) amorphous carbon films with a local configuration and properties ranging between those of graphite (sp2 hybridization) and diamond (sp3), (ii) ordered graphite Sims including carbon multi wall tubes, (iii) nanocrystalline diamond. The processes leading to the different carbon structures will be highlighted through experimental data and molecular dynamic situations. 1 Y. Lifshitz, S.R. Kasi and J.W. Rabalais, ''Subplantation Model for Film Growth From Hyperthermal Species: Application to Diamond'', Phys. Rev. Lett., 62, 1290, 1989. 2 Y. Lifshitz, G.D. Lempert, E. Grossman, ''Substantiation of Subplanta-tion Model for Diamondlike Film Growth from by Atomic Force Microscopy'', Phys. Rev. Lett., 72 (17), 2753, 1994. 3 S. Uhlmann, Th. Frauenheim, Y. Lifshitz, Molecular Dynamics Study of the Fundamental Processes Involved in Subplantation of Diamondlike Carbon, Phys. Rev. Lett., 81(3), 641, 1998. 4 H.Y. Peng, N. Wang, Y.F. Zheng, Y. LifshitB, J. Kulik, R.Q. Zhang C. S. Lee and S.T. Lee, Smallest Diameter Carbon Nanotubes, Appl. Phys. Lett., 77(18), 2831, 2000. 5 Y. Lifshitz, Th. Kcoumlhler, Th. Frauenheim, I. Guzmann, A. Hoffman, R.Q. Zhang, X.T. Zhou, S.T. Lee, The mechanism of diamond nucleation from energetic species, Science, 297, 1531, 2002. 6 Y. Lifshitz, R. M. Meng, S.T. Lee, R. Akhveldiany and A. Hoffman, Visualization of Diamond Nucleation and Growth from Energetic Species, Phys. Rev. Lett., 93(5), 56101, 2004