GRAPHENE GROWTH ON ELECTRODEPOSITED Ni/Cu SUBSTRATE

Abstract

Graphene is well-known for its high potential in various applications, including structural, optoelectronic, and sensing. Chemical vapor deposition (CVD) has emerged as the best choice for the repetitive production of high-quality graphene, with good control over the number of atomic layers present in the structure over the last decade. Cu and Ni are the most commonly used substrate materials for graphene synthesis via CVD due to their unique capability of carbon dissolution and reprecipitation. While Cu substrate is preferred for growing single- or bi-layer graphene due to its lower C solubility, Ni substrate is preferred for growing few-layer graphene (3-10 layers) due to its higher C solubility. Polycrystalline materials were mostly used as substrates, and the effect of grain size and texture of the substrate material was noticed to have an impact on graphene morphology and, thus, on properties. As grain boundaries and other defects in the substrate have been shown to induce defects in graphene, efforts have been made to synthesize large-area, defect-free graphene that will be best suited for next-generation electronic devices. Thus, a fundamental understanding of the growth mechanisms on different substrates is required to understand the dependence of graphene morphology and properties on different substrate textures. Electrodeposition has emerged as a viable method for producing textured substrates by varying parameters such as current density, overpotential, electrolyte composition, bath temperature, and so on. Although controlling the substrate microstructure and texture via electro-deposition has been investigated, the control of microstructure and texture via pulse reverse electrodeposition gives much more advantages than direct current (DC) electrodeposition, including the reduction of additives and thus less impurity content and the reduction of residual stresses, which results in reduced surface roughness. Since the quality of graphene depends on substrate structure, suggesting that the underlying substrate influences the nucleating carbon species during growth. Hence, in this work, we set out to explore the graphene growth on pulse reverse electrodeposited Cu and Ni substrate and further the effect of crystallographic orientations on the quality of graphene.