Experimental and theoretical characterization of integrated field emission nanotips

Abstract

An experimental and theoretical analysis of integrated nanotips and field emission arrays is presented in this article. Atomic force and scanning electron microscopy techniques were used to characterize the morphology of the monotips apex. Different positions of the tip with respect to the extraction lenses and morphologies were observed leading to different values of the tip emission current. Numerical calculations were performed considering the integrated tip as an electrostatic two-dimensional system allowing study of potential distributions, electrostatic fields near the tip apex, current density of emitted electrons, and electron trajectories. The correlation between experimental and theoretical results allows us to better understand the effect that the geometrical properties of the integrated nanotips, such as misalignments or morphology failures, produce on the emission current. Experiments and theory support the idea that the best emission is obtained for centered sharper tips with their apex localized at the level of the extraction lenses. Furthermore, slight modifications of the tip geometry lead to significant changes in the current distribution of emitted electrons.