The interaction between H and CH₃ of adsorption on the diamond (100)-2 × 1 surface based on DFT Calculations

In this research, the interaction mechanism between H and CH₃ of chemisorption on diamond (100)-2 × 1 surface was studied through the density functional theory (DFT) method. The H or CH₃ adsorbates were assumed to be directly chemisorbed to the final position on the surface in thermodynamic studies. The adsorption energies of individual H and CH₃ chemisorbed on the diamond surface were calculated, respectively. Subsequently, the adsorption energies for another H or CH₃ in five different positions adjacent to the initial H or CH₃ were calculated and compared. We find the universal law of the most likely chemisorption position. The results revealed that when one carbon atom of the dimer chemisorbed one radical, the other carbon atom of the dimer generated a dangling bond and had more ability to chemisorb other radicals. Therefore, the growth rate is faster along the direction of the carbon dimer than in other directions during the growth of the diamond film. The dimer is exactly towards the [110] direction. As films thicken, diamond tends to grow along the [110] direction. Therefore, it could explain that the [110] texture appears easily in the experiment. And, the results can be used to analyze the detailed process relative to the growth of the diamond film.