Growth and photoluminescence of self-assembled islands obtained during the deposition of Ge on a strained SiGe layer
Growth and photoluminescence of self-assembled islands obtained during the deposition of Ge on a strained SiGe layer
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DOI：
10.1016/j.optmat.2004.08.004
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发表时间：
2005-02
影响因子：
3.9
通讯作者：
D. N. Lobanov;A. Novikov;N. Vostokov;Y. Drozdov;A. Yablonskiy;Z. F. Krasilnik;M. Stoffel;U. Denker-U.-D
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文献类型：
--
作者：
D. N. Lobanov;A. Novikov;N. Vostokov;Y. Drozdov;A. Yablonskiy;Z. F. Krasilnik;M. Stoffel;U. Denker-U.-D
研究了应变Si 1 − xGe x（0<x<20%）层上Ge（Si）自组装岛的生长及其光致发光。当预沉积的Si 1 −xGexalloy中的Ge含量增加时，岛的尺寸和密度都增加。增加的岛密度与SiGe沉积后增强的表面粗糙度相关。岛的大小增加是由于增强Si混合和润湿层厚度的减少。后者是由SiGe层中弹性应变能的积累引起的。岛屿大小和密度的增加导致相邻岛屿之间的强烈相互作用。岛-岛相互作用导致岛自序，这是使用表面自相关函数进行分析。岛中较低的Ge含量解释了所观察到的岛相关光致发光信号的蓝移。我们观察到一个室温下的光致发光信号的Ge岛上生长的预沉积的SiGe合金，这是高于Si（001）上生长的Ge岛。这一结果可以通过岛密度的增加来解释，这提供了一种有效的方式来捕获岛中的电荷载流子。
The growth and photoluminescence of Ge(Si) self-assembled islands on strained Si1−xGexlayers (0<x<20%) has been investigated. Both island size and density increase when the Ge content in the predeposited Si1−xGexalloy increases. The increased island density is associated with an enhanced surface roughness after SiGe deposition. The increased island size is attributed to enhanced Si intermixing and to a wetting layer thickness reduction. The latter is caused by accumulation of elastic strain energy in the SiGe layer. The increase in both island size and density leads to a strong interaction between neighboring islands. The island-island interaction results in island self-ordering, which is analyzed using a surface autocorrelation function. The lower Ge content in the islands accounts for the observed blueshift of the island related photoluminescence signal. We observe a room temperature photoluminescence signal for Ge islands grown on a predeposited SiGe alloy which is higher than for Ge islands grown on Si(001). This result is explained by an increased island density, which provides an efficient way to capture charge carriers in the islands.