環状ダークフィールド電子顕微鏡による原子対原子構造および化学分析
Ondrej L Krivanek1, Matthew F Chisholm, Valeria Nicolosi
1Nion Co., 1102 8th Street, Kirkland, Washington 98033, USA. krivanek@nion.com
Nature
|March 26, 2010
まとめ
研究者は,先進的な伝送電子顕微鏡を用いて,超薄な材料のあらゆる原子を画像化し,特定することができます. この画期的な発見により,六角性酸ボロンなどの材料における原子置換と歪曲の詳細な分析が可能になった.
科学分野:
- マテリアルサイエンス 材料科学
- ナノテクノロジー ナノテクノロジー
- アナリティカル・ケミストリー (Analytical Chemistry) とは
背景:
- 伝送電子顕微鏡 (TEM) は,長い間,原子レベルのイメージングを想定されてきました.
- 偏差修正光学は,TEM能力を大幅に向上させました.
- 非周期性,多元素物質の全ての原子を解明し,特定することは,依然として課題です.
研究 の 目的:
- 超薄い材料における原子単位画像と化学的識別を実証する.
- 単層六角性ボンニトリド (h-BN) の置換欠陥を分析する.
- 原子規模の構造的歪みの直接的な解決を達成するために.
主な方法:
- 偏差修正スキャニング伝送電子顕微鏡 (STEM) を利用し,環状ダークフィールド (ADF) 画像を用いた.
- STEMを低電圧で操作し,感度が向上しました.
- 密度関数理論 (DFT) の計算を検証するために使用した.
主要な成果:
- 単層 h-BN.の各原子の化学型を解決し,特定しました.
- 3種類の置換欠陥の検出と特徴付け:BのC,NのC,NのO.
- 置換によって引き起こされる約0.1 Åの直接観測された平面内歪み.
結論:
- 超薄板の放射線損傷に耐性のある原子について,原子ごとに構造的および化学的分析が可能になりました.
- この技術は,原子規模の欠陥とその物質構造への影響について前例のない洞察力を提供します.
- この発見は,2D材料とナノ構造物の高度な特徴化への道を開く.
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