Growth and characterization of heteroepitaxial Bx C layers on 4H-SiC substrates for neutrons detection


Boron carbide (Bx C) is a semiconductor ceramic, better known and used for its mechanical and/or neutron-absorbing properties than for its electronic ones. This is probably due to a lack of understanding of its intrinsic semiconducting properties, which determination requires the prior elaboration of Bx C crystals of sufficient quality and purity. As the crystal growth of this material is very difficult, the literature data is both scarce and scattered, making it difficult their interpretation.

Recently, the LMI laboratory demonstrated the heteroepitaxy of Bx C by CVD on a silicon carbide substrate (4H-SiC). These single-crystalline layers have been characterized mainly from the structural point of view. Their electronic and optical properties have yet to be determined. The INL laboratory is specialized in characterizing semiconductor materials using a variety of techniques: structural (X-ray diffraction, electron microscopy); optical (Raman, Photoluminescence, Photoreflectance) and electrical (basic characterizations using mercury probe C(V) and 4-point resistivity, and more advanced ones with Hall effect and deep level spectroscopy).

This thesis will be carried out under the joint supervision of LMI and INL. These two Lyon-located laboratories are participating in the CADOR ANR project (ANR-23-CE08-0030), which aims to produce a new generation of neutron detectors based on the Bx C/4H-SiC heterostructure. The PhD student recruited for this project will play an active role in its realization, by finely characterizing Bx C thin films and optimizing deposits for neutron detectors.

During this thesis, the PhD student will learn to use an epitaxy machine (at LMI) for elaborating Bx C layers, which he/she will then characterize at INL using the various techniques mentioned above. The candidate will thus contribute to the synergy between the two laboratories, enabling decisive advances both in the knowledge of this material and in the manufacture of neutron detectors.

Required skills

The candidate will have a thorough background in materials science and/or semiconductors, with strong interest in experimentation and with autonomy.

A good level of English (writing and speaking) is required (TOEIC > 750).

Contract and salary

36-month full-time fixed-term contract starting at the beginning of September 2024.

Salary: 2,100 € gross per month in 2024, gradually rising to 2,300 € gross in 2026.

Scientific supervisors

Laboratoire des Multimatériaux et Interfaces – UMR 5615

UCB Lyon 1, Bat. Chevreul

Institut des Nanotechnologies de Lyon – UMR 5270

UCB Lyon1, Bat. Irène Joliot Curie