Degenerate four wave mixing spectroscopy of oxygen vibrations in amorphous silicon

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• 作者：Wells ; J.-P.R. ; van Hattum ; E.D. ; Phillips ; P.J. ; Carder ; D.A. ; Habraken ; F.H.P.M. ; Dijkhuis ; J.I.
• 关键词：61.43.Dq ; 78.47.+p ; 78.30.Ly ; 63.50.+x ; Vibrational dynamics ; Amorphous silicon ; Coherent transient ; Free electron laser
• 刊名：Journal of Luminescence
• 出版年：2004
• 期刊代码：54_00222313
• 类别：ch
• 出版时间：June, 2004
• 卷：108
• 期：1-4
• 页码：173-176
• 文件大小：390 K

摘要

We report on DFWM spectroscopy on the asymmetric stretching mode in a-SiO_x with x from 0.1 to 1.11. For a-SiO_0.1, a 10K lifetime of 2.8ps is obtained using laser-induced transient grating spectroscopy. Two-pulse photon echo measurements reveal phase dynamics having a temperature dependent component due to elastic phonon scattering and an excitation dependent component suggesting the presence of non-equilibrium Si–Si modes. At high excitation densities, the DFWM signal is dominated by a quasi-thermal grating whose population decay is extremely long lived (mg align=center border=0 SRC=/images/glyphs/BML.GIF>1ns). This effect is enhanced as the oxygen concentration is increased.