Kinetics of graphitization of thin diamond-like carbon (DLC) films catalyzed by transition metal

Abstract

In this paper, we have studied the kinetics of graphitization at 773 K of thin diamond-like carbon (DLC) films coated with minute amount of Ni metallic particles. DLC films are deposited at room temperature by pulsed laser deposition (PLD) on a transparent quartz substrate, and Ni is deposited on the surface of DLC using molecular beam epitaxy technique at room temperature. The ultra-high vacuum thermal (range 573–873 K with 60 min annealing treatments) and kinetic (range 30–3760 min at 773 K) behaviors of the deposited films are investigated. Surface and interface characterizations indicate that the growth of graphitic sp2 clusters starts at temperatures lower than 573 K. The kinetics of graphitization is recorded at 773 K. Thus, the continuous growth of graphitic clusters leads to a long-range kinetics. These clusters are responsible for the increase in the electrical conductivity and carrier mobility, reaching values of 6.103 Siemens/cm and 20 V/cm2 × s, respectively. This continuous change is not only explained by the nucleation and growth of graphitic clusters, but also by some reorientation of them alongside both the surface and the quartz substrate. The obtained results demonstrate that thermally post-treated catalytic metal/DLC films are promising materials for conductive electrodes and sensing applications.Prime novelty and projected interestKinetics of graphitization at 773 K of thin diamond-like carbon (DLC) films coated with minute amount of Ni metallic particles;High surface electrical conductivities, which are quite promising and competitive in comparison to literature data dealing with transparent electrodes.Correlation between conductivity models and Raman measurements in Catalytic Metal/DLC material.