Ge Growth on Partially and Entirely Ag Covered Si(111)
Ge Growth on Partially and Entirely Ag Covered Si(111)
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Ge 在部分和全部 Ag 覆盖的 Si(111) 上生长
DOI：
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发表时间：
2010
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通讯作者：
A. Locatelli
中科院分区：
文献类型：
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作者：
T. Schmidt;M. Speckmann;J. Falta;T. Menteş;M. Niño;A. Locatelli
用低能电子显微镜、低能电子衍射和X射线光电子显微镜研究了Ge在Ag：Si(111)-√3×√3-R30°衬底上的生长。对于温度为5 5 0°C的亚单分子层吸附，银端的√3×√3-R30°磁区装饰了衬底的台阶边缘。在这种阶梯状边缘修饰表面上的润湿层生长和Ge岛形核与在裸露的Si(111)-7×7上生长的Ge非常相似。在Ge沉积过程中，√3×√3-R30°磁畴溶解，并形成了分布在整个表面上的小的以Ag为端面的3×1磁畴。只有在三维(3D)Ge岛的周围才能发现较大的3×1磁畴。从Ge 3d岛的形态、尺寸分布和密度可以看出，在这种亚单分子层的Ag预吸附情况下，Ag对生长动力学和岛的几何形状的影响很小。这对于在完全覆盖的Ag：Si(111)√3×√3-R30°表面上生长Ge是完全不同的。与在裸露的Si(111)-7×7衬底上生长相比，扩散长度显著增加，导致岛密度急剧降低。此外，在此区域内，银的预吸附对岛的形态也有很大的影响。我们看到的不是三角形岛屿，而是形状不规则的巨大岛屿，它们更像是一部不连续的GE电影。[doi：10.1380/ejssnt.2010.221]
The growth of Ge on Ag:Si(111)-√3×√3-R30° has been studied by low-energy electron microscopy (LEEM), low-energy electron diffraction (LEED) and x-ray photoemission electron microscopy (XPEEM). For submonolayer adsorption of Ag at 550°C, the Ag terminated √3×√3-R30° domains decorate the step edges of the substrate. The wetting layer growth and Ge island nucleation on such a step-edge decorated surface is quite similar to Ge growth on bare Si(111)-7×7. During Ge deposition, the √3×√3-R30° domains dissolve and small Ag terminated 3×1 domains are formed that are distributed over the whole surface. Larger 3×1 domains are found only at the circumference of the three-dimensional (3D) Ge islands. From the Ge 3D island morphology, size distribution and density it is concluded that in this submonolayer Ag pre-adsorption scenario there is only little influence of the Ag on the growth kinetics and island geometry. This is completely different for Ge growth on an entirely covered Ag:Si(111)√3×√3-R30° surface. As compared to growth on bare Si(111)-7×7, a strong increase of the diffusion length is observed that leads to a drastic reduction of the island density. Also the island morphology is strongly affected by Ag pre-adsorption in this regime. Instead of triangular islands, we observe huge, irregularly shaped islands that rather resemble a discontinuous Ge film. [DOI: 10.1380/ejssnt.2010.221]