著者

石岡 邦江

出版者

一般社団法人日本物理学会

雑誌

日本物理學會誌 (ISSN:00290181)

巻号頁・発行日

vol.69, no.10, pp.721-722, 2014-10-05

著者

石岡 邦江 長谷 宗明 北島 正弘 丑田 公規

出版者

公益社団法人 日本表面科学会

雑誌

表面科学 (ISSN:03885321)

巻号頁・発行日

vol.24, no.5, pp.288-294, 2003-05-10 (Released:2009-01-25)

参考文献数

16

被引用文献数

2 2

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Coherent lattice oscillation can be excited in semimetals and semiconductors with femtosecond optical pulses. The dephasing of the coherent phonons, typically in the picosecond time scale, is dominated by the interaction with photo-excited carriers, incoherent (thermal) phonons, and defects such as impurities and vacancies. Here we present our femtosecond pump-probe study on the relaxation dynamics of the coherent phonons and the photo-excited carriers in ion-irradiated semimetals and semiconductors. The dephasing rate of the coherent optical phonon in bismuth is increased linearly with increasing ion dose due to the scattering by irradiation-induced defects. The dose dependence of the relaxation of the coherent acoustic phonon of graphite is quantitatively explained by a simple model in which a propagating wave is scattered by single vacancies, whereas that of the optical phonon by a modified mass-defect scattering model. In GaAs, the relaxation dynamics of LO phonon-plasmon coupled modes and photo-excited carriers provide quantitative information of carrier trapping due to vacancies.