第124回先端計測オープンセミナー
In-situ experiments on low-dimensional materials inside the transmission electron microscope
開催日: 2018.05.10 終了
日時
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講演者
表題
講演要旨
The first part of the talk discusses the idea of electron irradiation damage in a very beam-sensitive material - hexagonal boron nitride. I will show that the interplay between electron irradiation and sample temperature allows us to obtain a wide range of new structures. This includes well-known defects with triangular symmetry, but also completely new configurations, such as hexagonal-shaped and boron-terminated vacancies or - in more extreme cases - boron nitride atomic chains. Due to the nature of the experiments, these structures can be immediately characterized. The data is discussed in relation to various damage mechanisms, showing that the transformations are determined by an interplay between electron irradiation and thermally-enhanced reconstructions. In support of these findings, I will show that electron beam damage in this material can be completely avoided by overlapping the sample with a monolayer of graphene.
The second part of the talk shows data acquired on carbon nanotubes and CdS nanowires inside the TEM, using a combination of commercial and custom-made instrumentation. This approach is centered on sample holders which allow for an optical fiber and/or a metallic probe to be positioned close to the region of interest of the sample, via a piezoelectric mechanism, with nanometer precision. Firstly, I will show the possibility of mapping the luminescence centers in CdS nanowires through cathodoluminescence. The results reveal the distribution of centers with nanometer-precision, and then associate them to various intrinsic defects in CdS. Subsequent experiments improve on the previous method and describe optoelectronic measurements. CdS nanowires are probed before, during and after mechanical bending, revealing details such as their optical ON/OFF ratios and wavelength-dependent photocurrent generation. Lastly, I will introduce the idea of carbon nanotube telescoping and highlight the stability of these structures, which remain electrical conductive while extended and recover their initial properties once retracted, over the course of several cycles.
関連ファイル・リンク
- 先端材料解析研究拠点プロジェクト
- (旧)先端材料計測技術の開発と応用プロジェクトホームページ
- 先端材料解析研究拠点
イベント・セミナーデータ
- イベント・セミナー名
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第124回先端計測オープンセミナー
In-situ experiments on low-dimensional materials inside the transmission electron microscope - 会場
- 国立研究開発法人 物質・材料研究機構
千現地区 研究本館8階 中セミナー室 - 開催日: 時間
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2018.05.10
15:00~16:00 - 参加料
- 無料
お問合わせ
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国立研究開発法人 物質・材料研究機構 先端材料解析研究拠点運営室
Tel:029-859-2643/2839
Fax:029-859-2801
E-Mail: amc=ml.nims.go.jp([ = ] を [ @ ] にしてください)
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