简介: |
Optical second harmonic generation (SHG) measurement has been widely used to characterize the structure of organic thin films, including Langmuir films on the water surface, where non-linear optical susceptibilities of organic films which originates from arrangement of molecules and non-linear molecular susceptibility are well probed [1]. However once we focus on the electric fields coming out from electrons and dipoles, which are governed by the Gauss law, we can extend the SHG measurement to probe carrier motion and induced polarization in organic thin films, including in domains of monolayer [2,3]. Here by using a novel optical second harmonic generation technique, we visualize carrier motions in organic devices [4,5], i.e., organic field transistors, organic electroluminescence, etc., as well as polarized domain structure in Langmuir films [6].
Probing and modeling of carrier motions in organic materials is a fundamental research subject in science and electronics. According to the Maxwell’s electromagnetic field theory, injected carriers polarize organic materials. Thus by probing nonlinear dielectric polarization induced in active layer of organic devices by moving electrons, we can visualize and model carrier motion in organic devices. The method used here is a novel optical method based on electric field induced optical second harmonic generation (EFISHG) measurement [2-4]. In this presentation, basic concept for probing dynamical carrier motions by using EFISHG is discussed. Then using ambipolar organic field transistors, we show how carrier motion is visualized by the EFISHG measurement, and also show how carrier path is modeled based on the visualized carrier motion.
Also we here introduce the advanced conventional optical secodharmonic generation measurement cupled with the Brewster Angle Microscope(BAM), which is capable of visualizing polarization structure of Langmuir-monolayers [6]. We then demonstrate that the domian shapes of mixed lipid layers which are visualized by SHG and BAM are the same, but we can see textures originated from induced dipoles, differennt from domain patters.
References
1 Y. R. Shen, The Principles of Nonlinear Optics. , New York, Wiley 2002.
2 M. Iwamoto, T. Manaka, T. Yamamoto, and E. Lim, Thin Solid Films 517, 1312 ( 2008).
3 M. Iwamoto, T. Manaka, M. Weis, and D. Taguchi, J. Vac. Sci. Technol. B 28 C5F12 (2010).
4 T. Manaka, E. Lim, R. Tamura and M. Iwamoto, Nature Photon. 1, 581 (2007).
5 Y.Mashiko, D.Taguchi, M.Weis, T.Manaka and M.Iwamoto, Appl. Phys. Lett. 101, 243302 (2012)
6 Y.Matsuoka, D.Taguchi, T.Manaka and M.Iwamoto, Thin Solid Films, in press.
个人简介：
Prof. Iwamoto is world-famous in the field of Organic Materials Electronics, Dielectrics Physics, Electrical Insulation and Dielectrics Engineering research. He is a Fellow of Japan Applied Physics Society (JSAP) and a fellow of IEICE Japan (IEICE), and has won many awards. He has written over 10 books or book chapters, and published more than 450 papers in international Journals, including Nature, Nature Photonics, Physical Review Letters, Physical Review B, Physical Review E, Journal of Applied Physics, Applied Physics Letters, Journal of Chemical Physics, Chemical Physics Letters, Europhysics Letters, Euro Physics E, Thin Solid Films, IEEE on Electrical Insulation, Journal of Physics D, Japanese Journal of Applied Physics , J.Chem. Phys.Letters, J. Physics and Chemistry, J.Colloid and Interface Science, etc. He has been invited for more than 70 invited lectures as plenary and invited speakers at International conference, and served as conference chair of ICNME (International Conference on Nano-Molecular electronics), 10 times, M&BE (Molecular and Bio-electronics) international conference of JSAP and IDCNICE (International Discussion conference on Nano-interface controlled electronics)(Japan-Korea international conferences for 5 times and
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