Hourani W, Periwal P, Bassani F, Baron T, Patriarche G, Martinez E
Univ. Grenoble Alpes, F-38000 Grenoble, France.
Nanoscale. 2015 May 14;7(18):8544-53. doi: 10.1039/c4nr07503j.
The nanoscale chemical characterization of axial heterostructured Si1-xGex nanowires (NWs) has been performed using scanning Auger microscopy (SAM) through local spectroscopy, line-scan and depth profile measurements. Local Auger profiles are realized with sufficient lateral resolution to resolve individual nanowires. Axial and radial composition heterogeneities are highlighted. Our results confirm the phenomenon of Ge radial growth forming a Ge shell around the nanowire. Moreover, quantification is performed after verifying the absence of preferential sputtering of Si or Ge on a bulk SiGe sample. Hence, reliable results are obtained for heterostructured NW diameters higher than 100 nm. However, for smaller sizes, we have noticed that the sensitivity factors evaluated from bulk samples cannot be used because of edge effects occurring for highly topographical features and a modified contribution of backscattered electrons.
通过扫描俄歇显微镜（SAM），利用局域光谱、线扫描和深度剖析测量对轴向异质结构的Si1-xGex纳米线（NWs）进行了纳米尺度的化学表征。利用足够的横向分辨率实现局域俄歇剖面图，以分辨出单根纳米线。突出显示了轴向和径向的成分不均匀性。我们的结果证实了Ge径向生长在纳米线周围形成Ge壳的现象。此外，在验证了块状SiGe样品上不存在Si或Ge的优先溅射后进行了定量分析。因此，对于直径大于100 nm的异质结构纳米线，获得了可靠的结果。然而，对于较小尺寸的纳米线，我们注意到由于高地形特征产生的边缘效应以及背散射电子贡献的改变，无法使用从块状样品评估得到的灵敏度因子。
