Shear stress measurements on InAs nanowires by AFM manipulation

A novel approach to measure the lateral friction force between elastic InAs nanowires and a Si02 surface by AFM manipulation is presented. The method is based on the observation that for an ideal elastically deformed wire pinned by adhesion forces to a flat surface and in equilibrium between static friction forces and restoring elastic forces, the most tightly bent regions contain information about the maximal static friction force, that is, about the shear stress. It is based on the fact that an elastically deformed wire is kept in equilibrium by counterbalancing static friction forces and restoring elastic forces. The friction force can be deduced from the radius of curvature of the NW, assuming that the elastic properties of the wire are known. The method also offers a new path to determine important interactions between nanoscale objects and surfaces of different materials.