Graphene Synthesis on Single-Crystalline Cu(111) Substrate—A Study on Wrinkle Formation and Density

Chemical vapor deposition (CVD) has emerged as an effective method for synthesizing large-area graphene, yet achieving reproducible synthesis of wrinkle-free, single-crystal graphene remains challenging. Recent studies have shown that wrinkle-free, single-crystal graphene can be synthesized using 500nm single-crystal Cu(111) film on sapphire as substrate. However, the role of Cu(111) thin film in suppressing the formation of wrinkles on as-grown graphene has not been understood thoroughly.<br/>In our study, we developed recipes for single-crystal, large-area graphene on Cu(111) foil and ultra-flat graphene on Cu(111) film/sapphire. Through comparing the wrinkle density of graphene produced by these two methods, we investigated the influences of Cu(111) substrates (thin film vs. foil), and growth parameters towards wrinkle formation. And we compared the respective strengths of these two recipes, which are suitable for different applications. Our stable, highly-reproducible low-pressure (LP) CVD recipe on single-crystal Cu(111) foil produces centimeter-sized, low-defect, single-crystal graphene. While graphene grown on 500nm-700nm Cu(111) film/sapphire is ultra-flat with much fewer wrinkles. This detailed study on wrinkle formation and density holds promise for advancing the understanding and accessibility of high-quality graphene synthesis.