Field emission from atomically thin edges of reduced graphene oxide

Point sources exhibit low threshold electron emission due to local field enhancement at the tip. The development and implementation of tip emitters have been hampered by the need to position them sufficiently apart to achieve field enhancement, limiting the number of emission sites and therefore the overall current. Here we report low threshold field (< 0.1 V/μm) emission of multiple electron beams from atomically thin edges of reduced graphene oxide (rGO). Field emission microscopy measurements show evidence for interference from emission sites that are separated by a few nanometers, suggesting that the emitted electron beams are coherent. On the basis of our high-resolution transmission electron microscopy, infrared spectroscopy, and simulation results, field emission from the rGO edge is attributed to a stable and unique aggregation of oxygen groups in the form of cyclic edge ethers. Such closely spaced electron beams from rGO offer prospects for novel applications and understanding the physics of linear electron sources.