Strong oscillations detected by picosecond ultrasonics in silicon:: Evidence for an electronic-structure effect -: art. no. 125208
Strong oscillations detected by picosecond ultrasonics in silicon:: Evidence for an electronic-structure effect -: art. no. 125208
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DOI：
10.1103/physrevb.70.125208
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发表时间：
2004-09-01
影响因子：
3.7
通讯作者：
Côte, R
中科院分区：
文献类型：
--
作者：
Devos, A;Côte, R
我们展示了在不同激光波长下对生长在硅 (100) 基板上的不同样品进行皮秒超声实验的结果。在蓝色范围内，我们报告了反射率曲线的强烈振荡。我们提出了实验和数值结果，确定了硅基板中强声光相互作用中这些振荡的起源。然后，我们建议通过与落在同一范围内的硅中直接带间跃迁的关系来解释这些振荡的高振幅。这一解释得到了另外两个实验证据的支持：首先，当激光波长围绕带间跃迁调谐时，观察到检测到的信号的相位发生突然变化。其次，我们报告了当基板被加热时这种相变的变化。这项研究表明，我们首先在金属薄膜中证明的带间跃迁对皮秒超声波研究的影响可以扩展到半导体。
We present the results of picosecond ultrasonic experiments performed at different laser wavelengths in different samples all grown on silicon (100) substrates. In the blue range we report on strong oscillations in the reflectivity curves. We present experimental and numerical results that identify the origin of these oscillations in a strong acousto-optic interaction in the silicon substrate. Then we propose to explain the high amplitude of these oscillations by a relation with direct interband transitions in silicon which fall in the same range. This explanation is supported by two other experimental evidences: First, sudden changes in the phase of the detected signal are observed as the laser wavelength is tuned around the interband transitions. Second, we report on a shift of this phase change as the substrate is heated. This study shows that the effect of interband transitions on picosecond ultrasonic studies we had first demonstrated in thin metallic films can be extended to semiconductors.