Transfer patterning of large-area graphene nanomesh via holographic lithography and plasma etching

The authors present a high-throughput fabrication technique to create a large-area graphene nanomesh (GNM). A patterned negative photoresist layer was used as an etch mask atop chemical vapor deposition grown graphene on Cu foil. Shielded by the periodic nanopatterned photoresist mask, the graphene layer was selectively etched using O₂ plasma, forming a GNM layer. A poly(methyl methacrylate) layer was spun on the GNM atop copper foil, and the GNM was subsequently transferred onto a SiO₂/Si substrate by etching away the copper foil. Large-area (5 × 5 cm), periodic (500 and 935 nm in pitch), uniform, and flexible GNMs were successfully fabricated with precisely controlled pore sizes (200-900 nm) and neck widths (down to ∼20 nm) by adjusting the pattern generation of holographic lithography and the O₂ plasma etching process parameters. This holographic lithography-based transfer method provides a low-cost manufacturing alternative for large-area, nanoscale-patterned GNMs on an arbitrary substrate.