Influence of molybdenum concentration on the microstructure and nanotribological properties of diamond-like carbon films

We demonstrate how doping of non-hydrogenated diamond-like carbon (DLC) films doped with molybdenum (up to 6.2 at.%) can increase the hardness of the DLC surfaces up to 60% and reduce the sliding friction on them up to 25%, as measured on micro/nanometer scales. The films were prepared by DC magnetron sputtering on silicon (100) substrate. AFM, EDX, Raman spectroscopy and nanoindentation were used to study the influence of molybdenum concentration on the surface morphology, elemental composition, bonding structure, friction force, and nano-hardness of the films. Surface roughness and sp 3 /sp 2 ratio were also estimated as a function of the Mo concentration. In this way, our study extends previous investigations on comparable films on larger length scales. Applications in micro/nanoelectromechanical systems, magnetic storage devices and solid-state batteries are foreseeable.