Large lateral contact stiffness on Si nanopillar surfaces

We studied the lateral contact stiffness (k(contact)(x)) between the tip of a frictional force microscope and a pillar surface to identify the sliding behavior of the tip at the submicrometer scale. The k(contact)(x & nbsp;)and mean lateral force (& lang;F & rang;) were systematically measured as functions of pillar diameter phi. We found that the k(contact)(x & nbsp;)on a single Si pillar surface increased whereas the & lang;F & rang; rapidly decreased as phi decreased from the micrometer to the nanometer scale. This contradiction could be explained by the change in tip behavior from dynamic sliding to static sticking.& nbsp;(c) 2022 Author(s).