Structural properties of protective diamond-like-carbon thin films grown on multilayer graphene

Abstract

In spite of the versatility of electronic properties of graphene, its fragility and low resistance to damage and external deformations reduce the practical value of this material for many applications. Coating of graphene with a thin layer of hard amorphous carbon is considered as a viable solution to protect the 2D material against accidental scratches and other external damaging impacts. In this study, we investigate the relationship between the deposition condition and quality of diamond-like-carbon (DLC) on top of multilayer graphene by means of molecular dynamics simulations. Deposition of carbon atoms with 70 eV incident energy at 100 K resulted in the highest content of sp(3)-bonded C atoms. An increase of the number of dangling bonds at the interface between the top graphene layer and the DLC film indicates that decrease of the incident energy reduces the adhesion quality of DLC thin film on graphene. Analysis of radial distribution function indicates that sp(3) hybridized carbon atoms tend to grow near already existing sp(3) -atoms. This explains why the quality of the DLC structures grown on graphene have generally a lower content of sp(3) C atoms compared to those grown directly on diamond. Ring analysis further shows that a DLC structure grown on the sp(2) -rich structures like graphene contains a higher fraction of disordered ring structures.