Fabrication of graphene nanogap with crystallographically matching edges and its electron emission properties

We demonstrate the fabrication of graphene nanogap with crystallographically matching edges on $SiO2/Si$ substrates by divulsion. The current-voltage measurement is then performed in a high-vacuum chamber for a graphene nanogap with few hundred nanometers separation. The parallel edges help to build uniform electrical field and allow us to perform electron emission study on individual graphene. It was found that current-voltage (I-V) characteristics are governed by the space-charge-limited flow of current at low biases while the Fowler–Nordheim model fits the I-V curves in high voltage regime. We also examined electrostatic gating effect of the vacuum electronic device. Graphene nanogap with atomically parallel edges may open up opportunities for both fundamental and applied research of vacuum nanoelectronics.