Characterization and modification of the mechanical and surface properties at the nanoscale

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.