New synthesis route for isotope controlled boron nitride crystals and their properties

• Project/Area Number: 18K19136
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 36:Inorganic materials chemistry, energy-related chemistry, and related fields
• Research Institution: National Institute for Materials Science
• Principal Investigator: TANIGUCHI Takashi 国立研究開発法人物質・材料研究機構, 機能性材料研究拠点, フェロー (80354413)
• Project Period (FY): 2018-06-29 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000); Fiscal Year 2019: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2018: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
• Keywords: 窒化ホウ素 / 高圧合成 / 同位体濃縮 / 複分解反応 / 六方晶窒化ホウ素 / 立方晶窒化ホウ素 / 高圧下複分解反応 / 窒化ホウ素単結晶 / 超高圧合成

Outline of Final Research Achievements

Boron nitride crystals are known for low density hexagonal form (hBN) and high density cubic form (cBN). Although they have been applied in industry, effect of their isotope enrichment is still subject of study for exploring new functions. Metathesis reaction between boride and nitride compound near 3-5GPa region was successfully resulted in synthesis of isotopically pure hBN and cBN crystals. Linear relationship between Raman shit and their reduced mass was observed as an evidence of clear isotope effect. 10B and 11B enriched cBN crystals exhibit near two time increase of thermal conductivity at room temperature.

Academic Significance and Societal Importance of the Research Achievements

窒化ホウ素（BN）結晶において低密度の六方晶 (hBN)と高密度の立方晶 (cBN)結晶のホウ素同位体濃縮とその効果を明らかにすることを目的とした。優れた耐熱材、或いは超硬質材料であるhBN及びcBN結晶はワイドギャップ半導体としても優れた特性が期待されているが、そのホウ素同位体濃縮効果が興味深い。炭素の同位体効果が多角的に研究されているのに対して、窒化ホウ素(BN)結晶中のホウ素及び窒素同位体濃縮効果の研究は未踏であった。本研究はBN結晶の新たな高圧合成経路を開拓し、ホウ素同位体(10B及び11B)組成を任意に制御したhBNとcBN高品位単結晶を合成し、その基礎物性を明らかにした。

Research Products

• [Int'l Joint Research] MIT/University of Texas(米国)
• [Int'l Joint Research] 北京大学(中国)
• [Int'l Joint Research] MIT/テキサス大/ヒューストン大(米国)
• [Int'l Joint Research] テキサス大.学/MIT(米国)
• [Journal Article] Materials science research of boron nitride obtained at high pressure and high temperature (2020)
  • Author(s): T.Taniguchi
  • Journal Title: J. Ceramic Soc. Japan Volume: 128 Issue: 9 Pages: 620-626
  • DOI: 10.2109/jcersj2.20116
  • NAID: 130007895358
  • Peer Reviewed
• [Journal Article] Ultrahigh thermal conductivity in isotope-enriched cubic boron nitride (2020)
  • Author(s): K.Chen, B.Song, N. K. Ravichandran, Q. Zheng, X.Chen, H. Lee, H. Sun, S. Li, G. A.G. U. Gamage F.Tian, Z.Ding, Q.Song, A.Rai, H.Wu, P.Koirala, A. J. Schmidt, K. Watanabe, B. Lv, Z. Ren, L. Shi, D. G. Cahill,T.Taniguchi, D. Broido, G.Chen
  • Journal Title: Science Volume: 367 Issue: 6477 Pages: 555-559
  • DOI: 10.1126/science.aaz6149
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] High thermal conductivity of high-quality monolayer boron nitride and its thermal expansion (2019)
  • Author(s): Q. Cai, D. Scullion, A. Falin, K.Watanabe, T.Taniguchi, Y.Chen,E.J.G.Santos, L.H.Li
  • Journal Title: Science Advance Volume: - Issue: 6
  • DOI: 10.1126/sciadv.aav0129
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Single Crystalline Hexagonal Boron Nitride for Far UV Emission and Substrate for 2D Opto-Electric Devices (2019)
  • Author(s): 谷口 尚
  • Organizer: TWHM2019,Topical Workshop on Heterostructure Microelectronics 2019
  • Int'l Joint Research / Invited
• [Presentation] Synthesis of boron nitride and other 2D materials with solution growth and their impurity control (2019)
  • Author(s): 谷口 尚
  • Organizer: RPGR2019 (Recent Progress of Graphene and 2D materials 2019)
  • Int'l Joint Research / Invited
• [Presentation] h-BN: van der Waals 積層ヘテロ構造における絶縁材料 (2018)
  • Author(s): 谷口 尚
  • Organizer: 第79回応用物理学会秋季学術講演会
  • Invited
• [Presentation] Hexagonal boron nitride single crystals / Growth of BN (2018)
  • Author(s): T.Taniguchi
  • Organizer: The international workshop on nitride semiconductors (IWN 2018),
  • Int'l Joint Research / Invited
• [Presentation] High pressure synthesis of Boron Nitride crystals and impurity controls for their functionalizations (2018)
  • Author(s): T.Taniguchi
  • Organizer: the third International Conference of 2D Crystals (ICP2C3),
  • Int'l Joint Research / Invited
• [Patent(Industrial Property Rights)] 立方晶系または六方晶系窒化ホウ素を製造する方法 (2018)
  • Inventor(s): 谷口 尚、 渡邊賢司
  • Industrial Property Rights Holder: 国立研究開発法人 物質・材料研究機構
  • Industrial Property Rights Type: 特許
  • Filing Date: 2018