2002 Volume 45 Issue 4 Pages 561-566
We verify that ultrasonic atomic force microscopy (UAFM) can detect and evaluate subsurface objects with a resolution of around 10nm. We first show that the resonance frequency of UAFM cantilever shows a measurable change due to subsurface low-elasticity layer by a finite element analysis. We then proved the ability of subsurface imaging in a highly oriented pyrolytic graphite (HOPG) specimen. We found a new type of dislocation motion. As a load was applied to the tip, apparent edge-type dislocations (Frank partial dislocations) moved to the direction of climb over distances of 47nm and returned to the original position as the load was removed. To explain this motion, we propose a possible model where the extra half-plane of the dislocation is elastically compressed to shorten its length due to the normal load applied by the tip.