Electron field emission from graphene oxide wrinkles
We report a simple and general solution-based methodology to support reduced graphene oxide layers (rGO) onto micro-spikes engraved on Si to produce high-aspect ratio wrinkles and sharp protrusions. It is observed that as the number of deposited rGO layers is increased the wrinkle density progressively increases complemented by a remarkable folding of graphene sheets at the vicinity of the spike tips. Highly efficient and stable field emission with low turn-on fields was observed, attributed to the local enhancement of the electric field at the wrinkled rGO protrusions. The ability to produce wrinkled graphene from solution could allow large area deposition providing prospects for the development of practical electron sources and advanced devices based on graphene oxide field emitters. The contribution of this hierarchical, hybrid film morphology is evaluated and discussed.