| Summary: | In the past two decades much effort has been put in the characterization of the mechanical
and surface properties at the nano-scale in order to conceive reliable N/MEMS
(Nano and Micro ElectroMechanical Systems) applications. Techniques like nanoindentation,
nanoscratching, atomic force microscopy have become widely used to measure
the mechanical and surface properties of materials at sub-micro or nano scale. Nevertheless,
many phenomena such us pile-up and pop-in as well as surface anomalies
and roughness play an important role in the accurate determination of the materials
properties. The first goal of this report is to study the infulence of these sources of data
distortion on the experimental data. The results are discussed in the first experimental
chapter.
On the other hand, conceptors would like to adapt/tune the mechanical and surface
properties as a function of the required application so as to adapt them to the industrial
need. Coatings are usually applied to materials to enhance performances and reliability
such as better hardness and elastic modulus, chemical resistance and wear resistance.
In this work, the magnetron sputtering technique is used to deposit biocompatible thin
layers of different compositions (titanium carbide, titanium nitride and amorphous
carbon) over a titanium substrate. The goal of this second experimental part is the
study of the deposition parameters influence on the resulting mechanical and surface
properties.
New materials such as nanocrystal superlattices have recently received considerable
attention due to their versatile electronic and optical properties. However, this new
class of material requires robust mechanical properties to be useful for technological
applications. In the third and last experimental chapter, nanoindentation and atomic
force microscopy are used to characterize the mechanical behavior of well ordered lead
sulfide (PbS) nanocrystal superlattices. The goal of this last chapter is the understanding
of the deformation process in order to conceive more reliable nanocrystal
superlattices.
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