Synthesis and Applications of Large-Area Monolayer Graphene

Abstract

Graphene, renowned for its exceptional electrical, mechanical, and chemical properties, is a promising candidate for next-generation electronics, photonics, and biosensing. However, realizing its full potential depends critically on the ability to synthesize high-quality monolayer graphene. In this thesis, we present a robust chemical vapor deposition (CVD) approach for synthesizing large-area, adlayer-free, single-orientation graphene on Cu(111) foil and Cu(111) film/sapphire. A comparative analysis between these two substrates reveals critical differences in wrinkle density, grain size, and strain — offering insights for optimizing graphene growth. We further identify and characterize defective merging behavior in single-orientation graphene domains. Contrary to conventional assumptions, these merging regions contain permeable defects, revealing previously unrecognized limitations in using single-orientation stitched graphene as an impermeable barrier. To scale up production while reducing human error, we also develop an autonomous CVD platform with automated sample handling, growth and post-growth oxidation. This system enables high-throughput and reproducible graphene synthesis with minimal supervision. Building on these synthesis advances, we explore multiple applications of large-area monolayer graphene. We discover that graphene can promote interfacial oxidation of metals like aluminum and titanium during deposition, whereas metals such as nickel remain stable — a finding that informs the engineering of metal-graphene interfaces for electronic devices. In parallel, we explored diverse applications of graphene, including its role as a transparent, flexible electrode in organic solar cells, along with several collaborative efforts demonstrating its use as a sensor for cardiac microtissues, and as a tunable microheater in mid-infrared devices. Altogether, this work advances both the fundamental understanding and technological scalability of monolayer graphene, positioning it as a versatile platform for future applications across electronics, optoelectronics, and biointerfaces.