Cross-linked graphene layer embedded carbon film prepared using electron irradiation in ECR plasma sputtering

A new path to prepare cross-linked graphene layers embedded carbon (GLEC) films has been reported by introducing electron irradiation during the mirror-confinement electron cyclotron resonance (ECR) plasma sputtering process. The electron irradiation in the ECR plasma was identified by using Langmuir single probe equipped with a designed simulated substrate and the irradiation mode was found to be controlled directly by altering the substrate bias voltage. Cross-linked GLEC film was prepared using the electron irradiation in the pressure of 0.04 Pa and positive bias voltage of 50 V, and the nanostructure and binding configuration of the film were analyzed by high resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectroscopy (XPS). The results showed that GLEC film contains cross-linked graphene layers grown normally to the substrate surface when the content of sp2 hybridized carbon atoms in the film is more than 70%. The tribological behaviors of both cross-linked GLEC films and amorphous carbon films were compared using a Pin-on-Disk tribometer, and the mechanism for low friction coefficient was discussed by using HRTEM observation on wear track. The HRTEM results indicated that the cross-linked GLEC film has the potential to achieve low friction at the beginning of the friction.