The influence of a Si cantilever tip with/without tungsten coating on noncontact atomicforce microscopy imaging of a Ge(001) surface

Abstract

A sharp probe tip with atomic scale stability is essential and desirable for noncontactatomic force microscopy (NC-AFM) studies at the atomic scale. We observed a Ge(001)surface using both a Si cantilever and a tungsten coated Si cantilever at roomtemperature in order to investigate the influence of the tip apex structure on theNC-AFM images. By using the Si cantilever, we first obtained four types of image atthe atomic scale which can be explained assuming a dimer structure on the tipapex. On the other hand, the home-made tungsten coated tip, which has atomicscale stability and high electric conductivity, imaged the so-called ordered c(4 × 2) structure without any artifacts. The tungsten coated cantilever was found to havesignificantly higher performance for NC-AFM studies at the atomic scale than the Sicantilever.