GROWTH OF C36-FILMS ON DIAMOND SURFACE THROUGH MOLECULAR DYNAMICS SIMULATION

Abstract

In this paper, the initial stage of films assembled by energetic C 36 fullerenes on diamond (001)–(2 × 1) surface at low-temperature was investigated by molecular dynamics simulation using the Brenner potential. The incident energy was first uniformly distributed within an energy interval 20–50 eV, which was known to be the optimum energy range for chemisorption of single C 36 on diamond (001) surface. More than one hundred C 36 cages were impacted one after the other onto the diamond surface by randomly selecting their orientation as well as the impact position relative to the surface. The growth of films was found to be in three-dimensional island mode, where the deposited C 36 acted as building blocks. The study of film morphology shows that it retains the structure of a free C 36 cage, which is consistent with Low Energy Cluster Beam Deposition (LECBD) experiments. The adlayer is composed of many C 36-monomers as well as the covalently bonded C 36 dimers and trimers which is quite different from that of C 20 fullerene-assembled film, where a big polymerlike chain was observed due to the stronger interaction between C 20 cages. In addition, the chemisorption probability of C 36 fullerenes is decreased with increasing coverage because the interaction between these clusters is weaker than that between the cluster and the surface. When the incident energy is increased to 40–65 eV, the chemisorption probability is found to increased and more dimers and trimers as well as polymerlike- C 36 were observed on the deposited films. Furthermore, C 36 film also showed high thermal stability even when the temperature was raised to 1500 K.