Tip radius quantification using feature-size mapping of field ion microscopy images

Abstract

We are presenting a rapid and straightforward approach to determine the tip radius of sharp tungsten tips characterized by field ion microscopy. The utilization of certain features with well-known dimensions on the surface of these tips around the crystallographic [111] direction allows us to increase the accuracy of the radius measurement by almost one order of magnitude in comparison to standard methods. By employing a few reasonable approximations, it is possible to derive an analytical expression for the tip radius as a function of the observed feature size on the microchannel plate and some geometric parameters of the setup. Finally, we show that field ion microscopy images can be reconstructed on the atomic level by using a perfect hemisphere with the determined radius as a starting value and a low number of modifications in the topmost surface layers. In particular, this is useful for quantifying tip-sample interactions and characterizing material properties in atomic force microscopy.