Micro-structural and optical properties of diamond-like carbon films grown by magnetic field-assisted laser deposition

Abstract

Inhomogeneous magnetic field was introduced into pulsed laser deposition process, in order to discover new properties of diamond-like carbon film grown under magnetic field, offering the theoretical and experimental basis for furtherly enhancing sp<sup>3</sup>-bond content in this film. Distribution of the magnetic strength and flux lines induced by a rectangular permanent magnet was calculated. And then, flying trace of the carbon ions in the magnetic field was also simulated by the iterative method, which indicated that the carbon ions could not expand freely and they were restrained to accumulate around the center region of the magnet source. Besides the surface interference, measurement and the fitted results of ellipsometry parameters showed that magnetic field had important influence on layer-thickness distribution and optical constant of the pulsed laser deposition-grown diamond-like carbon film. Meanwhile, it was indicated that inhomogeneity of the layer-thickness distribution and optical constant increased when the magnetic strength was higher. Micro-structure of diamond-like carbon film was affected seriously by magnetic field, which was indicated by Raman spectra. Magnetic field could enhance the local stress in the carbon matrix net, increasing the sp<sup>3</sup>-bond content. Theoretical and experimental research showed that a suitable magnetic strength could excite micro-structure of diamond-like carbon film significantly, however, the high-quality diamond-like carbon coating with practical application value would be obtained by technological adjustment.