Dynamic and static responses of a piezoelectric actuator at nanometer scale elongations

The need of linear displacements in the nanometer range leads to the use of piezoelectric actuators in nanotechnology equipment. The aim of this paper is to present a new procedure to characterize a piezoelectric actuator at low excitation level corresponding to elongation at nanometer scale, in a scanning tunneling microscope. It is shown that the actuator dilatation is estimated using the tunnel current between a sharp tip fixed to the actuator and a metallic surface as a displacement sensor, and computing indirectly the unknown elongation from the physical constants of the metal under test in a theoretical law. Then, the actuator output elongation to input voltage signals is measured, via the tunnel current, to evaluate static and dynamic responses of the actuator. The proposed procedure will be used to obtain the input-output actuator model in order to implement its control