A study of initial stages for formation of carbon condensates on copper

Abstract

In the CVD method, samples of carbon condensates were obtained under special conditions (low substrate temperature and short growth times). The use of special technological conditions makes it possible to study the initial stages of growth of graphene layers. To analyze the influence of the microinhomogeneities of the copper substrate on growth conditions, various modes of its electrochemical polishing were used in the study. The structural state of the surface was studied using computer processing of digital images of a surface with color segmentation. A metallographic analysis of more than 70 samples was carried out and three main structural elements of the initial stage of growth of graphene layers were identified on the basis of computer image processing during condensation. These are graphene layers, sections of a copper substrate and a cluster of atoms with a structural state different from the graphene (presumably amorphous). It has been established that preparation of the substrate surface should be attributed to the most important technological operations for obtaining a high-quality graphene coating. It has been found that the use of multicomponent electrolytes during the polishing of the copper substrate makes it possible to increase the uniformity in the dimensions of the structural elements of the surface roughness. This leads to an increase in the surface area of the formation of graphene layers already during the initial stages of growth (at a relatively low process temperature of 700 °C). The obtained results testify to the prospects of using multistage image analysis (using the clustering method) to optimize the technological regimes for obtaining the “carbon condensate/substrate” systems, taking into account the initial roughness of the latter.