Fabrication of Graphene Quantum Dots from Chemical Vapor Deposited Graphene using Gold-incorporated Micelles as Etching Mask

Abstract

Graphene quantum dots (GQDs) are nano-sized graphene of a single layer or a few layers, with many unique optical, mechanical, and photoelectric properties induced by the quantum confinement effect and edge effect. Well-known techniques to prepare GQDs include electron beam lithography, chemical synthesis, graphene oxide reduction, and hydrothermal methods. We aimed in the present study to synthesize GQDs from the self-assembly of diblock copolymers. Diblock copolymer forms micelles in selective solvents. Polystyrene-block-poly(4-vinylpyridine) (PS-P4VP) block copolymer was used for nanostructure self-assembly, as metal precursors can be incorporated into the P4VP block. Block copolymer micelles were annealed with solvent vapor to fabricate cylindrical nanostructures on various substrates. Metal nanostructures were synthesized from metal-incorporated block copolymer nanostructures by oxygen plasma. The synthesized metal nanoparticles were used as etching masks to fabricate GQDs. We characterized the GQDs by Raman spectroscopy. Based on our observations, we speculated that various large-scale graphene nanostructures of well-defined geometry will be easily accessible for semiconductor applications.