Author/Authors :
Guggisberg، نويسنده , , M. and Bammerlin، نويسنده , , M. and Baratoff، نويسنده , , A. and Lüthi، نويسنده , , R. and Loppacher، نويسنده , , Ch. and Battiston، نويسنده , , F.M. and Lü، نويسنده , , J. and Bennewitz، نويسنده , , R. and Meyer، نويسنده , , E. and Güntherodt، نويسنده , , H.-J.، نويسنده ,
Abstract :
Force microscopy in atomic resolution with an oscillating tip has been performed across monatomic steps of the Si(111)-(7×7) surface using the tunnelling current or frequency shift as the feedback parameter. The contrast of simultaneously recorded images in both feedback modes is discussed. A significant difference between tip–sample interactions on the upper and lower terrace close to a step is analyzed in detail by means of Kelvin-type measurements. No contact potential variation across the step is found. A simple model for the force contrast is suggested which takes into account the different effective interaction areas or volumes on the upper and the lower terrace.
Keywords :
atomic force microscopy , surface structure , morphology , Roughness , Silicon , and topography
