Physical Vapor Deposition of Metal Nanoparticles on Chemically Modified Graphene: Observations on Metal–Graphene Interactions

TLDR

Understanding the interactions between metal atoms and graphene is crucial for controlling nanoparticle and thin‑film growth and for tuning the resulting charge transfer. The study investigates the growth of metallic nanoparticles on chemically modified graphene via physical vapor deposition. Physical vapor deposition was employed to deposit metal atoms onto CMG, enabling precise control over nanoparticle formation. Fine control of nanoparticle size (down to ~1.5 nm for Au) and coverage (up to 5 × 10⁴ μm⁻²) was achieved, with Au nanoclusters diffusing at room temperature and size distributions differing between single‑ and multilayer graphene; morphology varied by metal (Ti forming a uniform film, Ag forming droplets), and a simple model based on diffusion barriers and cohesive‑binding energy ratios explains these trends.

Abstract

Abstract The growth of metallic nanoparticles formed on chemically modified graphene (CMG) by physical vapor deposition is investigated. Fine control over the size (down to ∼1.5 nm for Au) and coverage (up to 5 × 10 4 μm −2 for Au) of nanoparticles can be achieved. Analysis of the particle size distributions gives evidence for Au nanocluster diffusion at room temperature, while particle size statistics differ clearly between metal deposited on single‐ and multilayer regions. The morphology of the nanoparticles varies markedly for different metals (Ag, Au, Fe, Pd, Pt, Ti), from a uniform thin film for Ti to a droplet‐like growth for Ag. A simple model explains these morphologies, based only on consideration of 1) the different energy barriers to surface diffusion of metal adatoms on graphene, and 2) the ratio of the bulk cohesive energy of the metal to the metal–graphene binding energy. Understanding these interactions is important for controlling nanoparticle and thin‐film growth on graphene, and for understanding the resultant charge transfer between metal and graphene.