Missions

Thanks to its large bandgap of 4.8 eV, beta-Ga2O3 is an excellent candidate for semiconductor-based devices operating at high temperatures. In addition, it can withstand high electric fields (breakdown field of 8MV/cm), making it worthy of interest for high-power/high-voltage applications, in competition with GaN, SiC, and diamond. Several markets are targeted, both military and civil, in particular the electronics market for electric vehicles, or the distribution of electrical energy from wind farms or photovoltaic panels.

At GEMAC, we are developing the Ga2O3 compound by heteroepitaxy on sapphire and homeoepitaxy on a Ga2O3 substrate. The growth technique is Metal-Organometallic Vapour Phase Epitaxy (MOVPE, MOCVD). We characterise the morphological, structural and electrical properties of thin films for applications in power electronics. This theme is shared by 'Semiconductors' and 'Physics of multifunctional materials' teams.
This 18-month post-doctoral contract is part of the European SAFEPOWER project 'Safer and More Reliable WBG/UWBG-Based MVDC Power Converters'. It is a HORIZON-CL5-2024-D3-01 project, coordinated by CSIC Barcelona. Specifically, the mission will be to study the properties of Ga2O3 thin films from the laboratory.

Activités

In collaboration with the consortium partners, Ga2O3 materials will be developed for the fabrication of MESFET, JFET and heterojunction pn diode devices. As part of a team of seven people at GEMAC, the post-doc will study the films properties using X-ray diffraction, atomic force microscopy (AFM), I(V), C(V), Hall-van der Pauw temperature measurements, and corrected transmission electron microscopy (STEM). Optical lithography + sputtering techniques will be used to prepare the electrical contacts. The focus will be on the link between growth conditions and structural/electrical properties in order to control the electrical transport of doped and undoped layers. The post-doc (M/F) will be strongly involved in the synthesis and presentation of results at European consortium meetings (and conferences), as well as writing progress reports and publications

Compétences

Experience in semiconductor physics and characterisation (as part of a thesis).
Theoretical knowledge :
- condensed matter
- electrical transport in semiconductors
- crystallography
Skills
- Experimental and teamwork skills
- Follow safety rules
- Communication and writing skills in English

Contexte de travail

The position is at GEMAC, a joint research unit under the affiliation of CNRS and University of Versailles Saint-Quentin-en-Yvelines. GEMAC is located on the UFR des sciences campus in Versailles. It is also affiliated to the Université Paris-Saclay. The post-doctoral student (M/F) will be part of the "Semiconductor Group" of the laboratory.
Gallium oxide Ga2O3 is a well-known oxide. Its crystalline structure has 5 polymorphs, and the beta crystalline phase is the most widespread because it is the most stable, up to 1800°C. This is the phase that the scientific community is the most interested in, and has become heavily involved in recent years. International research is very active on the subject, and numerous Ga2O3-based electronic components have already been reported in the literature. The state of the art includes the demonstration of vertical NiO/Ga2O3 heterojunction diodes with a breakdown voltage of 9 kV (https://doi.org/10.1116/6.0002722). Beta-Ga2O3 can be produced in bulk form by various methods, with ingot diameters of up to 6 inches. Good-quality substrates are available on the market, and this availability is vital for the industrial development of this oxide.
.The experimental work is in the field of condensed matter physics: characterisation and properties of semiconductor materials.
The post-doctoral student will have access, either by him/herself or through internal collaboration, to all the experimental facilities available at GEMaC, Versailles, as well as to the STEM Corrected microscope at the LEM, Chatillon, France.

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

The position is located in a sector under the protection of scientific and technical potential (PPST), and therefore requires, in accordance with the regulations, that the recruitment is authorized by the competent authority of the MESR.