Accurate determination of atomic positions of surface hydrogen using new RHEED method

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01819
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 29020:Thin film/surface and interfacial physical properties-related
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: FUKAYA Yuki 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 原子力科学研究所 先端基礎研究センター, 研究主幹 (40370465)
• Co-Investigator(Kenkyū-buntansha): 福谷 克之 東京大学, 生産技術研究所, 教授 (10228900)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 電子回折 / 水素 / 表面

Outline of Final Research Achievements

In this study, we improved a reflection high-energy electron diffraction (RHEED) apparatus and investigated RHEED conditions sensitive to the atomic positions of hydrogen on material surfaces by intensity simulations in order to determine the atomic positions of hydrogen on material surfaces with high accuracy. The RHEED apparatus improved make it possible to measure rocking curves and azimuthal plots from surfaces at low temperatures. Under the specific conditions found by intensity simulations, rocking curves and azimuthal plots were measured for hydrogen-adsorbed Ni(111) and Pd(001) surfaces. In particular, a definite change in the intensities due to the hydrogen adsorption was obtained at a few degrees off from the symmetric azimuth. Consequently, we found that through the combined use of the advanced RHEED apparatus and intensity simulations, RHEED technique is useful for the determination of the atomic positions of hydrogen on material surfaces.

Free Research Field

表面科学

Academic Significance and Societal Importance of the Research Achievements

物質表面における水素原子の吸着・拡散について理解は、基礎・応用の両面からその重要性が認識されているが、いまだに不明な点が多い。これは、物質表面上の水素の位置が実験的に特定困難であることによる。本研究成果により、物質表面における水素の位置決定及び水素の振る舞いの理解が促進し、クリーンなエネルギー媒体として重要な水素の新たな利活用への展開も期待される。