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Sujet de stage / Master 2 Internship

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Elaboration of oxinitride BaTi(OxN1-x)3 thin films by atomic plasma assisted molecular beam

Contact: BARBIER Antoine, , antoine.barbier@cea.fr, +33 1 69 08 39 23
Summary:
The objective of the internship is to grown thin BaTi(OxN1-x)3 oxinitride thin films by oxygen and nitrogen plasma assisted molecular beam epitaxy. We will proceed by nitrogen doping of BaTiO3 for which the growth conditions are perfectly mastered in the CEA/SPEC laboratory. The study will be completed by macroscopic characterizations of the ferroelectric and/or photoelectrolytic behaviors. Complementary measurements may be realized at synchrotron-SOLEIL.
Possibility of continuation in PhD: Oui
Deadline for application:30/04/2019

Full description:
Oxynitrides are a class of compounds with a broad spectrum of exploitable properties for a wide variety of applications ranging from UV absorbers (to sustain fragile organic compounds), to semiconductors (suitable for photovoltaic), photocatalytic and photoelectrolysis devices to magnetic compounds. The insertion of nitrogen, less electronegative than oxygen, into the lattice of an oxide causes an increase in the covalent nature of the chemical bonds. This leads to a decrease of the optical gap, Eg, value and thus in a modification of the absorption properties of the compound as well as doping by charge carriers making it possible to envisage new transport properties. The production of single crystalline thin oxynitride films is however challenging and has been little studied to date.
We will explore the possibility of modulating the properties of thin films of barium titanate, BaTiO3, a ferroelectric oxide. Its growth conditions are already well mastered and we will proceed by the addition of nitrogen plasma during growth. Doping rates will remain low. Ideally, the ratio between the loss of ferroelectricity and the gain of activity as a photoanode in the photoelectrolysis of water will be quantified. X-ray diffraction measurements may be used to characterize the material developed on the DiffAbs line at the SOLEIL synchotron.

Contacts: BARBIER Antoine, +33 1 69 08 39 23, antoine.barbier@cea.fr ; Other researchers: H. Magnan, J.-B. Moussy et C. Mocuta (Synchrotron-SOLEIL)
Technics/methods used during the internship:
The candidate will address the UHV techniques associated with the growth by molecular beam epitaxy. The techniques that will be used are Reflexion High Energy Electron Diffraction (RHEED), Auger Electron Spectroscopy (AES), Photoemission core level spectroscopy (XPS), Piezo Force Microscopy (PFM), Low Energy Electron microscopy (LEEM) and eventually X-ray diffraction on the DIFFABS beamline of synchrotron SOLEIL.

Laboratory
Tutor of the internship

 

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