KPFM imaging of Si(1 1 1)53×53-Sb surface for atom distinction using NC-AFM

We investigate the possibility of distinction of individual atom species using noncontact atomic force microscopy (NC-AFM) combined with the electrostatic force (ESF) measurement. We simultaneously measured the topography and the surface potential on the Si(1 1 1)53×53-Sb surface by Kelvin probe force microscopy (KPFM). The surface potential image indicates the existence of two kinds of adatoms while the difference is not clear in topography. Atom species of each adatom are specified from other NC-AFM images with different experimental conditions and therefore spots with a lower surface potential are specified as Si adatoms. It is found that, in addition to adatoms, Si rest atoms can be specified from the surface potential image. The result indicate that KPFM has the ability to distinguish the individual atom species on intermixing surfaces.