Peculiarities of image acquirement and analysis in AFM electrical modes

Abstract

The paper describes the peculiarities of acquirement and interpretation of images of current distribution through the sample surface when operating in I-AFM mode. It shows that I-AFM and SCM modes can be successfully used only for small scanning fields (no more than 5x5 square micrometer), since during the scanning process the continuous change in the area of the probe tip and, therefore, in the contact area between the probe and the sample surface is observed because of the abrasion of the tip. At the same time electrical modes of AFM could not be recommended for the investigation of nano objects, because there appear a number of difficulties in results interpretation, caused by the big curvature radius of the probe tip and, therefore, by the big surface area of electrical contact. The paper also demonstrates the peculiarities of acquirement and interpretation of CVCs for individual points on the sample surface in I/V Spectroscopy mode. It is shown that it is practically impossible to use I/V Spectroscopy mode for additional investigation of the surface by acquiring of CVCs in the points of interest (where heterogeneities in topography or current through the surface are observed) on the sample surface in I-AFM mode, because of the big temperature drift and hysteresis of piezoceramics. Recommendations for improving the possibilities of the method are given in the paper.