Axially heterostructured nanowires are a promising platform for next generation electronic and optoelectronic devices. Reports based on theoretical modeling have predicted more complex strain distributions and increased critical layer thicknesses than in thin films, due to lateral strain relaxation at the surface, but the understanding of the growth and strain distributions in these complex structures is hampered by the lack of high-resolution characterization techniques. Here, we demonstrate strain mapping of an axially segmented GaInP-InP 190 nm diameter nanowire heterostructure using scanning X-ray diffraction. We systematically investigate the strain distribution and lattice tilt in three different segment lengths from 45 to 170 nm, obtaining strain maps with about 10⁻⁴ relative strain sensitivity. The experiments were performed using the 90 nm diameter nanofocus at the NanoMAX beamline, taking advantage of the high coherent flux from the first diffraction limited storage ring MAX IV. The experimental results are in good agreement with a full simulation of the experiment based on a three-dimensional (3D) finite element model. The largest segments show a complex profile, where the lateral strain relaxation at the surface leads to a dome-shaped strain distribution from the mismatched interfaces, and a change from tensile to compressive strain within a single segment. The lattice tilt maps show a cross-shaped profile with excellent qualitative and quantitative agreement with the simulations. In contrast, the shortest measured InP segment is almost fully adapted to the surrounding GaInP segments.

轴向异质结构纳米线是下一代电子和光电设备的有前途的平台。基于理论模型的报告预测，由于表面的横向应变松弛，与薄膜相比，更复杂的应变分布和临界层厚度会增加，但是由于缺乏高应力，阻碍了对这些复杂结构的生长和应变分布的理解。分辨率表征技术。在这里，我们展示了使用扫描X射线衍射对轴向分段的GaInP-InP 190 nm直径纳米线异质结构的应变映射。我们系统地研究了从45到170 nm的三个不同段长的应变分布和晶格倾斜，获得了约10 ^-4的应变图相对应变敏感性。实验是在NanoMAX光束线上使用直径为90 nm的纳米焦点进行的，利用了来自第一个衍射极限存储环MAX IV的高相干通量。实验结果与基于三维（3D）有限元模型的实验的完整模拟非常吻合。最大的片段显示出复杂的轮廓，其中在表面的横向应变松弛导致不匹配界面的圆顶形应变分布，以及单个片段内从拉伸应变到压缩应变的变化。晶格倾斜图显示了一个十字形轮廓，与模拟的定性和定量一致性极佳。相反，最短的测量InP段几乎完全适应了周围的GaInP段。