纳米材料与分子纳米技术杂志

Field Emission Simulations of Carbon Nanotubes and Graphene with an Atomic Model

Fernando Fuzinatto Dall?Agnol and Daniel den Engelsen

Field Emission Simulations of Carbon Nanotubes and Graphene with an Atomic Model

Most models of field emission from carbon nanotubes (CNTs) and graphene sheets consider the geometry of the emitter tip as a smooth spherical surface. In these models, indicated with the terms simplified geometry (SG), the electronic distribution is not taken into account. However, the electronic distribution is concentrated around the atoms nuclei and their bonds forming hexagonal patterns that affect the field enhancement and largely determines the field emission. In this paper we evaluate the field emission in a SG-model and compare it with the emission in a ball-stick model that better represents the atomic structure at the surface of the emitter. We found that the emission current from open and capped carbon nanotubes and for graphene sheets is typically 10 times larger in the ball-stick geometry than in the SG. Furthermore, different morphologies of the CNT highlight the sensitivity of the emission current.