Principles of Atomic Force Microscopy

Abstract

The remarkable feature of Scanning Probe Microscopes (SPM) is their ability to “view” details at the atomic and molecular level, thus increasing our understanding of how systems work and leading to new discoveries in many fields. These include life science, materials science, electrochemistry, polymer science, biophysics, nanotechnology and biotechnology. In this report we present the principles of atomic force microscopy and describe the necessary components of such equipment. The essential property is the interaction force between the tip and the sample, which depends on their distance. At close contact the force is repulsive while at a larger separation the force is attractive. This results in different operation modes which should be chosen according to the characteristics of the sample, since each mode has different advantages. Atomic force microscopy is currently applied to various environments (air, liquid, vacuum) and types of materials such as metal semiconductors, soft biological samples, conductive and non-conductive materials. With this technique size measurements or even manipulations of nano-objects may be performed.