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Application of MIR-FEL Irradiation to Selectively Excite Phonons in Wide-gap Semiconductors

Research Abstract
A mid-infrared free electron laser (MIR-FEL) (5 – 20 µm) facility (KU-FEL: Kyoto University Free Electron Laser) was constructed to aid various energy science researchers at the Institute of Advanced Energy, Kyoto University. In May 2008, the first power saturation at 13.2 µm was achieved. A pilot application to evaluate selective phonon excitation processes in solid materials by irradiating with MIR-FEL was implemented, and a preliminary experiment without FEL irradiation was conducted. N-doped silicon carbide (SiC) was selected as a sample material due to its unique electrical property where the lattice vibration and the electronic structure are coupled. Two peaks, 1.8 – 2.2 eV and 2.4 – 2.8 eV, which showed strong temperature dependences in both their intensities and peak energies, were observed. These tendencies could be explained by using a donor-acceptor pair luminescence (DAP) model with impurity and defects in the SiC sample. The results imply that we can verify selective phonon excitation by investigating the change in the PL spectrum introduced by MIR-FEL irradiation.
Research Authors
Kyohei Yoshida, Taro Sonobe, M. A. Bakr, Y. W. Choi, Ryota Kinjo, M. Omer, Masato Takasaki, Satoshi Ueda, Naoki Kimura, Keiichi Ishida, Kai Masuda, Toshiteru Kii and Hideaki Ohgaki
Research Department
Research Journal
Journal of the Korean Physical Society
Research Member
Research Pages
NULL
Research Publisher
NULL
Research Rank
1
Research Vol
59-5
Research Website
http://www.kps.or.kr/jkps/abstract_view.asp?articleuid=DC4CB01B-5A34-44BB-AC39-3DB2F67BE3B5
Research Year
2011