学生の米澤さん、Yue Zhaoさんが11th International Symposium on Atomic Level Characterizations for New Materials and Devices '17において、Student Awardを受賞

 学生の米澤 隆宏さん(博士後期課程1年、応用物理学領域高村(由)研究室)、Yue Zhao(チョウ エツ)さん(博士後期課程3年、応用物理学領域水谷研究室)がハワイで 開催された11th International Symposium on Atomic Level Characterizations for New Materials and Devices '17において、Student Awardを受賞しました。

 Atomic Level Characterization (ALC)は日本学術振興会第141委員会が主催する国際シンポジウムです。無機、有機材料やバイオマテリアルなどのデバイスや新材料の原子レベルでの特徴付け、また、表面および界面におけるさまざまな分析・計測技術を議論する場となっています。ALC'17は、2017年12月3日~12月8日において、ハワイのAqua Kauai Beach Resortにて開催されました。今回のStudent Awardsは、総発表件数220件超の中から、7件に授与されたものです。


【米澤 隆宏さん】

 Atomistic study of GaSe/Ge(111) interface formed through van der Waals epitaxy

 Layered materials can be grown on various substrates through van der Waals epitaxy (VDWE) regardless of lattice mismatch. The atomic level study of the film-substrate in VDWE is becoming increasingly important due to their expected applications as 2D materials. In this contribution, we have grown GaSe thin films on Ge(111) substrates by MBE and studied the GaSe/Ge(111) interface using STEM and STM. Cross-sectional STEM observations revealed that the grown layers adopt predominantly the expected wurtzite-like structure and stacking, but monolayers with an unexpected, zinc-blende-like structure and other layer stacking sequences exist locally near the film-substrate interface. By STM, Moiré patterns indicating in-plane rotation of a few degree between GaSe(0001) and Ge(111) lattices were locally observed. These results demonstrate that even in VDWE, structural changes can occur in the grown layers adjacent to the substrate, highlighting the importance of such interface for synthesizing and applying ultimately thin 2D materials.

 この度、材料分析に関する権威ある国際学会 ALC におきまして、Student Awardを頂き大変光栄に思います。 本研究を進めるにあたり熱心にご指導を頂きました高村由起子准教授、大島義文准教授、アントワーヌ・フロランス助教にこの場をお借りして厚く御礼申し上げます。

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【Yue Zhaoさん】

 Observation of spider silk by femtosecond pulse laser second harmonic generation microscopy

 Spider silk has properties of high toughness and high strength and is being studied as attractive materials. Many marvellous molecular structures and mechanisms of spider silk have been discovered so far. Some researchers and manufacturers are trying to create artificial spider silk using biotechnology. The gene and amino acid sequences are known, and so it is easy to make raw protein of silk. However, it is a tremendous challenge to create it into a genuine silk. On the other hand, the reason for the high strength of spider silk is not well understood yet. In this study, spider silk was observed by using a homemade femtosecond laser second harmonic generation microscope. As a result, different nonlinear optical responses were observed in the radial line and spiral line of the spider web which look similar to the naked eyes. This SHG signal is suggested to be strongly correlated with the β-sheet structure of protein in the spider silk. A model of the microscopic structure of the spider silk was proposed. As shown in this study, the second harmonic generation image of spider silk reflects also what is happening in the spider's gland. Thus in the future, the secretory glands of the spider can be observed by this microscope to find the mechanism of the production of the silk.


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