The role of ion beam energy on nature of thin film of amorphous carbon (Sp2/Sp3) by ion beam deposition

Carbon ion energy is a key factor in determining the amount of sp3 bonds in the structure of the amorphous carbon film and its like-diamond nature. In this study, the structural evolution of diamond-like carbon coating based on the mechanism of sp3 bond formation of amorphous carbon under the influence of the ion beam energy in the radio frequency ion-beam deposition process were investigated. For this purpose, the parameter of ion beam energy was 200, 300, and 400 eV ​​ for the deposition of DLC coatings. Raman and X-ray spectroscopy (XPS) analyzes were used to evaluate the structure and chemical composition of the coatings. Also, in order to determine the effect of ion beam energy on the surface roughness and thickness of the applied coatings, atomic force microscope (AFM) and field emission scanning electron microscope (FESEM) were used. Hardness and elastic modulus were measured by nanohardness test. According to the results of Raman analysis, the lowest value of ID/IG ratio was obtained in ion beam energy of 300 eV, which was equal to 0.66. The results of XPS analysis showed the lowest amount of sp2 bonds in the diamond-like carbon film at ion beam energy of 300 eV. Also, results of AFM analysis showed at ion beam energy of 300 eV, the surface roughness of diamond-like carbon coating has the lowest value. Due to the highest amount of sp3 bonds in the ion beam energy of 300 eV, the diamond-like carbon coating had the highest hardness and was equal to 10.6 GPa.