The BONUS consortium aims at fabricating light-emitting devices for the deep ultraviolet (UV) by using hexagonal boron nitride (hBN). Such an objective requires to go beyond the existing collaborations and established contacts. The BONUS partners have to combine their work force, get funding for their activities and reach the synergy necessary for the realization of this project which is new, ambitious and high-risk. The BONUS consortium will answer to the EU call FET-Open Challenging Current Thinking (FETOPEN-01-2018-2019-2020) which deadline is May 13th, 2020. The provisional planning comprises two meetings in Montpelier, which will be the highlights of the proposition preparation before the submission of the BONUS project. The ANR-MRSEI grant will be decisive for the organization of these two meetings. The deep UV range (UVC-?<280 nm) is a strategic spectral domain, with numerous applications requiring the development of technological solutions which are cheap, compact and have a low energy consumption. The applications lie within the fields of chemistry and biology (for photo-catalysis, sterilization, and water-purification) but also of short-distance telecommunications in opaque atmosphere. Today, the only available devices are spectral lamps which are not compact, have a short lifetime and a low energy efficiency. The BONUS consortium proposes a radical new vision for the development of light-emitting devices in the deep UV. Instead of pursuing solutions in the mainstream AlGaN field, the BONUS partners intend to explore the extraordinary potential of hBN. Although hBN is a nitride semiconductor, its originality goes well beyond having the lightest cation (boron atom). hBN is a lamellar compound like graphite. Many unusual and fascinating properties derive from this structure, ranging from the genuine hyperbolicity in the mid-infrared, the existence of single photon sources, to a bright emission in the deep UV. hBN is a peculiar material, for which the study of its fundamental properties was triggered in 2004 by the first high-quality crystals grown by Watanabe and Taniguchi. In the last few years, the BONUS partners have become major players in the field with state-of-the-art contributions in epitaxy, characterization and spectroscopy. The BONUS consortium is composed of 6 partners (5 academic and 1 industrial) from 5 countries (France, Germany, UK, Spain and Switzerland). The fabrication of light-emitting devices in the deep UV relies on the epitaxy of hBN layers of high crystalline quality. Without epitaxy, it will be impossible to develop UV sources which are compact, cheap, efficient and with a long lifetime. Epitaxy is the absolute requirement for a disruptive technology in deep UV opto-electronics, with solid-state hBN-based devices. The composition of the BONUS consortium reflects this strategic priority with 3 partners working on epitaxy: AIXTRON (Germany), Nottingham University (UK) and GT-CNRS (Metz-France). The other 3 partners of BONUS bring complementary expertises in optical spectroscopy (L2C-CNRS, Montpellier-France), Raman characterization (CSIC, Barcelona-Spain) and the synthesis of bulk hBN crystals for homo-epitaxy (ETHZ, Zurich-Switzerland).

We intend to build an ITN proposal in order to train a generation of scientists with an unprecedented expertise in deep geothermal resources. As part of their training, PhD students will elaborate an original 3D model of the European Variscan-Alpine lithosphere based on the acquisition of new data complementing published work. This model will allow the quantification of mass and heat transfers at the scale of the lithosphere and the assessment of its stress state. These are prerequisites for future exploration for deep geothermal resources and will open the road to the transition to a CO2-free energy, as preconized by one of the focus of the H2020 program (Building a low-carbon, climate resilient future). The emerging view of energetic and mineral systems is to integrate multiscale and multidisciplinary approaches leading to a reasoned prediction of underground resources. Here we will apply this strategy at the European scale by developing a network of academic and private actors that bring together communities from complementary disciplines (geology, geochemistry, geophysics). We have identified a consortium grouping the main countries involved in deep geothermal exploration or in the elaboration of a geothermal model of Europe, namely France, Italy, Germany, Poland, Spain and Turkey. The ITN project will be coordinated by the CNRS (Geosciences environnement Toulouse). The coordinator, Stéphanie Duchene, is a professor in metamorphic geology at the Université Paul Sabatier, experienced in team management through the co-direction of the GET laboratory from 2012 to 2016. Through the definition of up to 15 PhD projects, we wish to train the next generation of scientists in the following key-research areas essential to assess the potential for deep geothermal i) characterization of the geology, petrophysics and geophysics on key-targets that represent different geothermal settings of the European Variscan-Alpine crust, ii) characterization of the contribution of the underlying mantle combining petrological-geochemical analysis of mantle xenoliths and joint inversion of geophysical data throughout Europe, iii) characterization of the present-day stress state and rheology in order to address potential fluid flow in the upper crust, iv) modeling of the thermal state at the scale of the European crust and at the scale of sites with potential for deep geothermal using geological and geophysical information, as well as the physical properties of rocks. The training program will aim at giving to the early career scientists a common background in i) the geological and geophysical methods and knowledge required to envision geothermal exploration applied in particular to the European Variscan-Alpine lithosphere, ii) the petrophysical and thermal properties of rocks necessary to model the thermal state and evolution of the crust, iii) the socio-economic of geothermal energy (techniques, risks, environmental and economic challenges related to energy transition). The outcomes of the project should be designed for the scientific community, companies engaged in the field of deep geothermal energy supply and decision makers. They should also comprise a data base and additional resources that may help to assess the geothermal potential and the challenges related to deep geothermal energy. The expected general contributions of the project will be to elaborate a common language between academic and private members as well as between specialists of different disciplines of Earth Sciences, to contribute to the training of a generation of scientists that may be employed both in academic and private organizations and to provide a geological and geophysical framework to qualify and quantify fluid and heat transfer at the scale of the lithosphere and thus revolutionize exploration for deep geothermal in Europe.