Surface stability and electronic structure of CuNi alloy (111) as a potential catalyst for graphene growth-a density-functional theory study

Abstract

Controlling the number of graphene layers during its growth is essential in realizing its practical application as a transparent conductive electrode. Growth with CuNi alloy catalysts can effectively control the number of graphene layers. However, research at the experimental level has not been supported by research at the theoretical level. Therefore, we will study the growth of graphene on a CuNi catalyst using the density functional theory (DFT). However, in this paper, we only focus on studying the stability of the surface of CuNi as a preliminary study. Based on geometry optimization, CuNi (111) has a wrinkled surface in the slab model due to the anisotropy shift of the atoms. Furthermore, CuNi (111) has a surface energy of 1.511 J/m2, which is between the surface energies of its components. This condition indicates that CuNi (111) has excellent stability. When forming CuNi alloy, electrons in the Cu 4s and Ni 3d orbitals have an enormous contribution in forming the metallic bonds indicated by a significant shift of the band center energy and change of the number of states at the Fermi level. Our results show that the CuNi system can become a potential catalyst for graphene growth.