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Laser-induced structural disordering and optical phase change in semimetal bismuth observed by Raman microscopy
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Title: | Laser-induced structural disordering and optical phase change in semimetal bismuth observed by Raman microscopy |
Authors: | Handegard, Orjan S. Browse this author | Kitajima, Masahiro Browse this author | Nagao, Tadaaki Browse this author →KAKEN DB |
Keywords: | Bismuth | Raman scattering | Microparticle | Laser heating | Optical phonon | Dielectric response |
Issue Date: | 15-Oct-2019 |
Publisher: | Elsevier |
Journal Title: | Applied surface science |
Volume: | 491 |
Start Page: | 675 |
End Page: | 681 |
Publisher DOI: | 10.1016/j.apsusc.2019.05.013 |
Abstract: | We observed strong enhancement of the Raman signal from a silicon (Si) substrate hidden beneath nano/microdroplets of bismuth (Bi) after exposing them to a high-power laser beam (785 nm). Confocal Raman microscopy indicated that the as-fabricated Bi droplets inhibit the Raman signal from the underlying Si substrate. After the laser flash heating step, the intensity of Si optical phonons was strongly enhanced at the positions of Bi droplets, becoming even more intense than that of the bare Si substrate. Analyses of the Bi optical phonon modes, E-g and A(1g), confirmed a loss of long-range ordered crystallinity in the laser exposed droplets. Such lattice disordering can increase the available free carrier density in semimetal Bi, as occurs in the case of its amorphous and liquid states. And this can induce an optical phase change, which causes a marked enhancement of Si Raman signals through an effect similar to surface-enhanced Raman scattering (SERS). |
Rights: | © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ | http://creativecommons.org/licenses/by-nc-nd/4.0/ |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/81129 |
Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 長尾 忠昭
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