Description du sujet de thèse

Photostriction in ferroelectric thin films

Ferroelectric materials (FE) have a spontaneous electrical polarization that can be controlled by applying an electric field. Moreover, the coupling of ferroelectric polarization with mechanical stress makes FEs very good piezoelectrics. Recently, the optical excitation of FE has revealed the existence of new physical phenomena, such as the anomalous photovoltaic effect and, in particular, photostriction (photoinduced deformation).

The aim of this thesis is to study the contribution of various key material parameters to the amplitude of photostriction. This will include characterizing the ferroelectric, photovoltaic and piezoelectric properties of oxide thin films, using different measurement techniques in C2N's cleanroom and in collaboration with CentraleSupelec's SPMS laboratory.

Techniques used: cleanroom processes (lithography, deposition, etching), electrical measurements (dielectric, ferroelectric, photovoltaic), deformation measurements (two optical interferometry setups) under voltage and/or laser excitation.

Qualities and skills required: experimental physics, with a background in materials science and/or solid state physics, teamwork.

Contexte de travail

The Centre of Nanosciences and Nanotechnologies - C2N (CNRS/Université Paris-Saclay), was created on June 1, 2016 at the heart of the Paris-Saclay campus. The center develops research in the fields of materials, nanophotonics, nanoelectronics, nano-bio-technologies and microsystems, as well as nanotechnologies. Over 400 people work at C2N, which is organized into four research departments and houses a 2900 m² technology center.
The OXIDE team in the Materials department at C2N carries out research into the growth of oxide thin films and their integration into new devices with advanced functionalities such as ferro-, thermo- or piezo-electricity.
The PhD student will join the OXIDE team, as part of a fundamental research project that has been awarded ANR funding. Part of the research activities will be carried out in collaboration with CentraleSupelec's SPMS laboratory.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

Specific safety training for the use of equipment in cleanrooms (chemistry).