Laboratoire des Matériaux Semiconducteurs (LMSC)and ‡Institute of Microengineering (IMT), Photovoltaics and Thin Film Electronics Laboratory, École Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland.
Nano Lett. 2014;14(4):1859-64. doi: 10.1021/nl4046312. Epub 2014 Mar 6.
Thanks to their unique morphology, nanowires have enabled integration of materials in a way that was not possible before with thin film technology. In turn, this opens new avenues for applications in the areas of energy harvesting, electronics, and optoelectronics. This is particularly true for axial heterostructures, while core-shell systems are limited by the appearance of strain-induced dislocations. Even more challenging is the detection and understanding of these defects. We combine geometrical phase analysis with finite element strain simulations to quantify and determine the origin of the lattice distortion in core-shell nanowire structures. Such combination provides a powerful insight in the origin and characteristics of edge dislocations in such systems and quantifies their impact with the strain field map. We apply the method to heterostructures presenting single and mixed crystalline phase. Mixing crystalline phases along a nanowire turns out to be beneficial for reducing strain in mismatched core-shell structures.
由于其独特的形态，纳米线使得材料的集成成为可能，而这在以前的薄膜技术中是不可能实现的。反过来，这为能源收集、电子和光电等领域的应用开辟了新的途径。对于轴向异质结构来说尤其如此，而核壳系统则受到应变诱导位错出现的限制。更具挑战性的是检测和理解这些缺陷。我们将几何相位分析与有限元应变模拟相结合，以量化和确定核壳纳米线结构中晶格变形的起源。这种结合为研究此类系统中边缘位错的起源和特征提供了有力的见解，并通过应变场图量化了它们的影响。我们将该方法应用于呈现单和混合结晶相的异质结构。事实证明，沿纳米线混合结晶相有利于减少不匹配核壳结构中的应变。
