Introduction
AFM has been employed in a variety of research fields including physics, chemistry, biology and engineering. In order to measure the force or potential energy between a small tip and a sample, a tiny probe called a cantilever is employed. The cantilever provides a force sensor and a force actuator. By pushing the cantilever to the sample, its topographic height can be measured, and the interacting force between the tip attached to the cantilever and the sample can be measured by pulling it. There are various methods for detecting the motion of the cantilever with nanometre scale accuracy. These include tunneling current measurement , optical deflection technique , fiber interferometry and piezoresistive methods.
