Simulation of the enhancement factor from an individual 3D hemisphere-on-post field emitter by using finite elements method

This paper presents a 3D computational framework for evaluating electrostatic properties of a single field emitter characterized by the hemisphere-on-post geometry. Numerical simulations employed the finite elements method by using Ansys-Maxwell software. Extensive parametric simulations were focused on the threshold distance from which the emitter field enhancement factor (γ) becomes independent from the anode-substrate gap (G). This investigation allowed demonstrating that the ratio between G and the emitter height (h) is a reliable reference for a broad range of emitter dimensions; furthermore, results permitted establishing G/h≥2.2 as the threshold condition for setting the anode without affecting γ. •The anode distance which affects the emitter field enhancement was investigated.•The ratio between the anode distance and the emitter height is a reliable reference.•The ratio G/h≥2.2 has been established as the anode threshold distance condition.