HIGH-RESOLUTION IMAGING OF CONTACT POTENTIAL DIFFERENCE WITH ULTRAHIGH-VACUUM NONCONTACT ATOMIC-FORCE MICROSCOPE

An ultrahigh vacuum scanning Kelvin probe force microscope (UHV SKPM) utilizing the gradient of electrostatic force, was developed based on an ultrahigh vacuum noncontact atomic force microscope (NC-AFM) capabl e of atomic level imaging, and used for simultaneous observation of co ntact potential difference (CPD) and NC-AFM images. CPD images of a Si (lll) surface with Au deposited, clearly showed the potential differen ce in phases between 7X7 and 5x2 structures. When Ag was deposited as a submonolayer on the Si(lll) 7x7 reconstructed surface, the atomic le vel lateral resolution was observed in CPD images as well as in NC-AFM topographic images. (C) 1998 American Institute of Physics.