The process of local-field-induced deposition on a surface facing a scanning tunneling microscope (STM) tip has been investigated for several tip-sample systems. Applying negative voltage pulses, atoms can be transferred from the STM tip to the surface and, for example, platinum dots and lines have been drawn on gold or silicon samples by this technique. In this latter case, a discussion is proposed on growth mechanisms involved in field-induced deposition processes on the basis of growth kinetics studies. When positive voltage pulses are applied to a silicon sample placed in tunneling conditions with a STM tip, silicon nanofeatures are elaborated on the substrate surface by field-enhanced surface diffusion of silicon atoms.

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Absfracf-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.