Optical characterization of strain-induced structural modification in SiGe-based heterostructures
Optical characterization of strain-induced structural modification in SiGe-based heterostructures
复制标题
SiGe 基异质结构中应变诱导结构改性的光学表征
DOI：
10.1063/1.369550
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发表时间：
1999
影响因子：
3.2
通讯作者：
Y. Shiraki
中科院分区：
文献类型：
--
作者：
N. Usami;K. Leo;Y. Shiraki
我们表明，应变引起的SiGe基异质结构的结构修改可以非破坏性地探测光致发光光谱与几个不同的激发波长。由于SiGe基半导体的间接能带结构，激发能量的适当选择导致光生载流子的产生深度的急剧变化，并允许探测样品在生长方向上的不同部分。利用这种技术，我们发现弛豫SiGe上的应变薄量子威尔斯阱几乎没有穿线位错，并且大部分穿线位错被限制在成分渐变的SiGe缓冲层中。此外，我们表明，在纯Ge/Si多量子威尔斯的应变积累导致的逐层生长模式在一定的临界数量的威尔斯。
We demonstrate that strain-induced structural modifications in SiGe-based heterostructures can be nondestructively probed by photoluminescence spectroscopy with several different excitation wavelengths. Owing to the indirect band structure of SiGe-based semiconductors, an appropriate choice of excitation energy leads to drastic change of the generation depth of photocarriers and allows to probe different part of the samples in the growth direction. By using this technique, we show that thin strained quantum wells on relaxed SiGe are almost free from threading dislocations and most of them are confined in composition-graded SiGe buffer layer. Furthermore, we show that the accumulation of strain in pure Ge/Si multiple quantum wells causes breakdown of the layer-by-layer growth mode at certain critical number of wells.