Detail of the subject:
The goal of this post-doctoral position is to probe the local polarisation in ferroelectric materials as a function of applied bias voltage across layers and the local effective dielectric constant in dielectric
materials. For doing that, the research project will consist in elaborating ferroelectric and dielectric thin layers in order to develop a special geometry incorporating a floating metallic electrode
connecting these materials to a reference capacitor of nanometric dimensions for electrical characterizations and mapping of the local potential when applying a bias.
First, model (amorphous and crystalline) nanodevices made of ferroelectrics (e.g: BaTiO3, HfO2) and dielectrics (e.g: Si3N4, ZrO2) with metallic electrodes (e.g: TiN, LaxSr1-xMnO3) will be grown by different
techniques present at SPEC and C2N (atomic layer deposition, oxygen-assisted molecular beam epitaxy and pulsed laser deposition) on doped-Si and Nb-doped SrTiO3 substrates.
Secondly, the work will be focused on the advanced electrical measurements of the different heterostructures. The as-grown films will be first electrically characterized at the local scale by atomic force microscopy in conductive mode (CT-AFM) to study the homogeneity of the electrical resistivity and by using piezo-response force microscopy (PFM) to investigate the arrangement of the electrical polarization in ferroelectric layers. The heterostructures will be then patterned into micro-capacitors in clean room at C2N and the electrical response of the devices, including capacitance and polarization measurements, will be measured at the macroscale.
The retained candidate will be shared between C2N and SPEC (University Paris-Saclay) according to the systems to elaborate and the electrical measurements to perform. The elaboration of different heterostructures will be realized at C2N and SPEC, while the PFM and advanced macroscopic
electrical measurements on nanostructured devices will be mainly performed at C2N.
The local picture and the global dielectric/ferroelectric study of the devices will be essential inputs for operando holography studies in which the young researcher will be also involved (ANR in progress).

Education: Doctorate in Nanoscience, Material Science, Solid State Physics or equivalent

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