Nanomaterials Field
High-Pressure Structural Controls Group
We promote basic research on various functional materials together with the advancement of high-pressure base technology.
Group Leader: Hitoshi Yusa
Functional materials unique to high-pressure synthesis: 2D materials and photoluminescence and fluorescent materials
Current Topics
Ga2O3, which is known as a power semiconductor, has a highly symmetrical corundum structure under high pressure. We doped Cr3+ into the high-pressure phase of Ga2O3 and synthesized high-quality corundum-type Ga2O3:Cr3+ crystals under high pressure. These crystals are green under visible light illumination, but under UV irradiation they exhibit a clear deep red fluorescence of the opposite color [3]. We have developed applications for these crystals on a pressure scale for a diamond anvil cell (DAC) [4].
Fig. 1. High pressure synthesis using a large-volume belt-type apparatus (left). High-purity hBN crystals (top) and black phosphorus thin film on a substrate (bottom).
Outline of Research
The high-pressure synthesis method using a belt-type appatus with a large volume enables the synthesis of various functional crystals unique to ultra high-pressure synthesis. 2-dimensional high-purity hBN crystals have been provided as insulating films for research on graphene-related materials, contributing to many international collaborative studies [1]. We have also succeeded in converting vapor-grown red phosphorus into black phosphorus in thin films, which is expected to be applied to near-infrared devices [2].
Fig. 2. High-pressure synthesized Ga2O3:Cr3+ corundum crystals (left). The absorption spectrum shows green (top), and it turns to red fluorescence under UV light (bottom), and it can be used for pressure measurement with DAC (right).
References
- Y. Guo, T. Taniguchi et al., Nature 630, 346–352 (2024). DOI: 10.1038/s41586-024-07438-5
- N. Higashitarumizu, T. Kawashima, H. Yusa et al., Nano Lett. 24(10), 3104–3111 (2024). DOI: 10.1021/acs.nanolett.3c04894
- H. Yusa, M. Miyakawa, Inorg. Chem. 63(5), 2695–2700 (2024). DOI: 10.1021/acs.inorgchem.3c04028
- H. Yusa, M. Miyakawa, J. Appl. Phys. 137(3), 035902 (2025). DOI: 10.1063/5.0246260
Group members
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Hitoshi Yusa・Group Leader -
Takashi Taniguchi・NIMS Fellow -
Fumio Kawamura・Principal Researcher -
Satoshi Nakano・Principal Researcher -
Masashi Miyakawa・Senior Researcher -
Tetsuya Kawashima・Senior Researcher
Activities
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Feb 26, 2024