Description du sujet de thèse

The research project aims to explore the physics of heat transfer through dry and wet nanocontacts between two solid objects. It is based on identified needs for the characterization of thermal conduction through nanocomposite systems ranging from nanostructured systems to single particles on a substrate. A plethora of high impact technologies (electronics systems, probe microscopies, thermal measurement method, heat-assisted magnetic recording drives…) is concerned.

Scientific context
In nanocomposite and nanostructured systems, a large density of interfaces and nanocontacts between the different involved materials controls heat dissipation. Despite numerous scientific studies on heat conduction in such systems, no experimentally-supported model has provided a definitive understanding of heat transfer through nanocontacts between two solid objects. Non-Fourier heat transport, anharmonic and electron-phonon scattering processes play in these systems essential important roles.

Research project
In this context the thesis research project concerns more specifically the experimental determination of the value of the thermal boundary resistance involved at nanocontacts with a size that varies between few nanometres to hundred nanometres. As interfaces and contacts can be discontinuous at the atomic or nanometric scales, the roughness of surfaces will be also considered.
Experimental work will be made by improving and applying an in-situ scanning electron microscopy scanning thermal microscope equipment to carefully measure the thermal boundary resistances at nanocontacts and then make it possible the comparison between simulations and measured data.
The analysis will focus on three preselected bulk materials, chosen because their difference in energy carriers (phonons or electrons) and their advantage of being little prone to oxidation, enabling therefore a rigorous modelling-experiment comparison Measurements will require the analysis of the mechanical and thermal behaviours of small self-heated tips with samples in different environmental conditions (relative humidity, pressure, temperature) and the development of a thermal measurement modelling taking into account the most influencing parameters (shape of the contact, roughness, water microstructure…).

Contexte de travail

This thesis will be carried out as part of a project funded by the ANR, the THACOS project for THermAl nanoCOntactS.
The work will be carried out on the DOUA campus at the Centre d'Energétique et de Thermique de Lyon (CETHIL) but also at the Institut Lumière et Matière (ILM).

Desired skills
You have a Master research project in experimental development and measurement. An experience in near field AFM and possibly (nano) thermal measurement and measurement would be a plus. Curious and open-minded, you are a person connected to the experimental bench, comfortable with experimental physics, you have knowledge of materials and electronic and you like disruptive nanotechnologies. Finally, you are comfortable in English, rigorous, motivated by taking risks.

Applications should include a detailed resume, a letter of motivation, the academic file (grades) of the 3 last years, and please provide also the names of two references (head of studies, previous advisor, …).