Sub-picosecond acoustic pulses at buried GaP/Si interfaces
Sub-picosecond acoustic pulses at buried GaP/Si interfaces
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DOI：
10.1063/1.4997913
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发表时间：
2017-08-07
影响因子：
4
通讯作者：
Stanton, Christopher J.
中科院分区：
文献类型：
--
作者：
Ishioka, Kunie;Rustagi, Avinash;Stanton, Christopher J.
我们报道了在三维半导体晶体中传播的超短声脉冲的光产生和检测。生长在Si（001）上的晶格匹配GaP层的光激发引起瞬态反射率的尖峰，这是由于在差距/Si界面处产生的声脉冲和在差距表面处检测到的声脉冲，反之亦然。反射率尖峰的极短宽度（0.5ps）将转化为3 nm或10个原子双层的空间范围，这与差距/Si界面处的混合层的宽度相当。反射率信号也被修改的准周期布里渊振荡所产生的声脉冲在差距和Si晶体中的传播。本研究结果表明，简单的光泵浦-探测方案在半导体埋层界面质量的无损评价的潜在应用。出版社：AIP Publishing
We report on the optical generation and detection of ultrashort acoustic pulses that propagate in three-dimensional semiconductor crystals. Photoexcitation of lattice-matched GaP layers grown on Si(001) gives rise to a sharp spike in transient reflectivity due to the acoustic pulse generated at the GaP/Si interface and detected at the GaP surface and vice versa. The extremely short width of the reflectivity spike, 0.5 ps, would translate to a spatial extent of 3 nm or 10 atomic bilayers, which is comparable with the width of the intermixing layer at the GaP/Si interface. The reflectivity signals are also modified by quasi-periodic Brillouin oscillations arising from the propagation of the acoustic pulses in the GaP and Si crystals. The present results demonstrate the potential applications of the simple optical pump-probe scheme in the nondestructive evaluation of the buried semiconductor interface quality. Published by AIP Publishing.