The atomic resolution imaging of metallic Ag(111) surface by noncontact atomic force microscope

Atomic resolution imaging of the Ag(lll) surface is demonstrated with the noncontact atomic force microscope (AFM)) using frequency modulation (FM) detection method in an ultrahigh vacuum at room temperature, for the first time. The constant excitation mode is used to suppress the destruction of the tip apex and sample surface, in which the constant amplitude voltage is supplied to piezoelectric scanner for cantilever oscillation. Trigonal pattern can be clearly seen. Measured distance between the protrusions is 2.8 +/- 0.1 Angstrom, which is in good agreement with the lattice spacing of Ag(lll) surface. The corrugation height is estimated to be 0.1-0.2 Angstrom. These results suggest that the noncontact AFM has potential for imaging pure metal surfaces with atomic resolution. (C) 1999 Elsevier Science B.V. All rights reserved.