Effect of tip morphology on AFM images

Abstract

The effect of tip morphology on the atomic force microscope (AFM) image contrast for a GaAs(110) surface is investigated theoretically by considering three different tip apexes of a Si tip: (1) Si apex with a half-filled dangling bond; (2) Ga apex with an empty dangling bond; and (3) As apex with a fully filled dangling bond. It is shown that the dangling-bond state of the tip apex has significant effects on the image contrast: the Ga apex will image the As sublattice, and the As apex will image the Ga sublattice, and in the case of the Si apex, it is possible to image only the As sublattice or both the As and Ga sublattices, depending on the tip–sample separation.