Contrast and Resolution of Nanowires in Electrostatic Force Microscopy

A detailed analysis of the contrast and lateral resolution between a dc-biased tip and metallic nanowires over a dielectric sample is presented. The theoretical technique used to analyze the interaction intrinsically includes the mutual polarization between the tip, the sample, and the metallic objects. A good selection of the dielectric constant of the sample is found to be critical since it can increase the contrast by more than an order of magnitude. On the other hand, the dielectric constant does not have any influence on the lateral resolution. In this case, the tip-sample distance and the tip radius are the most relevant parameters. For small tip-sample distances, the length of the nanowires must also be taken into account since it can produce differences of up to 20% in the lateral resolution.