Grand Séminaire d'Institut

Lundi 3 Juin 2024 à 10h30.

Recent Advances in Growing of Bulk Oxide Crystals using the "Oxide Crystal Growth from Cold Crucible (OCCC)” method. The business model in our laboratory's university-launched start-ups.

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At present, the growth of bulk high-temperature oxide crystals is usually carried out using precious metal crucibles. In recent years, the sharp increase in the price of such metals (especially Ir and Rh) has become a major issue in the production of these oxide crystals. This circumstance forces researchers to look for other methods for obtaining crystals. One of the most promising candidates is the cold container method. This method has been used for many years to produce ultra-high melting point crystals such as cubic zirconia. In this method, the material is kept in a molten state inside a water-cooled copper basket. In this case, heating is carried out using an RF coil due to the penetration of the field into the gaps between the tubes of the basket. Further, in the traditional cold container technique, the crystal can be grown in the melt volume by slowly raising the inductor. In the presented work, growth is carried out by contacting the seed with the melt and slowly pulling upward similar to the classical Czochralski method. We have labeled the proposed method, the “oxide crystal growth from cold crucible (OCCC)” method, which is a fusion of the skull-melting and Czochralski methods.

Using such technique makes it possible to solve several problems at once, namely: avoid using a metal crucible, avoid contact of the melt with the container, use any growth atmosphere, including pure oxygen. Using the proposed method, we successfully grew a range of different crystals: Ce-doped Gd-Al-Ga garnet, Gd-La silicate, LiTaO3, Ga2O3. The first two crystals showed scintillation properties comparable to crystals grown from Ir crucibles using the Czochralski method.

These R&D efforts were carried out jointly with C&A, a laboratory-based start-up company. "University-launched start-ups" are expected to create products and services based on university research results and contribute to the convenience and well-being of civil society through social implementation. In the talk, I will introduce the situation surrounding university-launched start-ups in Japan and the business model in our laboratory's university-launched start-ups. As examples of social implementation, I will also talk about the practical application of the garnet scintillator and the development of the OCCC method and the challenge of its industrialization.

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