Shape Modification of Germanium Nanowires during Ion Irradiation and Subsequent Solid-Phase Epitaxial Growth
Shape Modification of Germanium Nanowires during Ion Irradiation and Subsequent Solid-Phase Epitaxial Growth
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DOI：
10.1002/admi.201800276
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发表时间：
2018-07-09
影响因子：
5.4
通讯作者：
Hinks, Jonathan
中科院分区：
文献类型：
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作者：
Camara, Osmane;Hanif, Imran;Hinks, Jonathan
在离子辐照（通常用于带隙工程）过程中，纳米结构会经历离子诱导弯曲（IIB）现象。这种永久性变形背后的机制是争论的主题。在这项工作中，用30或70 keV的氙离子照射锗纳米线，以诱导远离或朝向离子束的弯曲。将实验结果与蒙特卡罗计算结果进行比较，发现弯曲方向取决于纳米线截面上的损伤分布。辐照后，纳米线在高达440℃的温度下退火，触发固相外延生长（SPEG），使变形的纳米线进一步改性。经过IIB后，观察到在SPEG过程中，向离子束方向弯曲的纳米线会变直，而向离子束方向弯曲的纳米线弯曲得更厉害。这是由于不同的机制负责离子束诱导弯曲在相反的方向。因此，本文报道的结果揭示了导致纳米线IIB的机制，并演示了如何预测纳米线在辐照和退火下的演变。最后，他们表明，在一定条件下，弯曲甚至可以通过SPEG消除。
During ion irradiation which is often used for the purposes of bandgap engineering, nanostructures can experience a phenomenon known as ion-induced bending (IIB). The mechanisms behind this permanent deformation are the subject of debate. In this work, germanium nanowires are irradiated with 30 or 70 keV xenon ions to induce bending either away from or toward the ion beam. By comparing experimental results with Monte Carlo calculations, the direction of the bending is found to depend on the damage profile over the cross section of the nanowire. After irradiation, the nanowires are annealed at temperatures up to 440 degrees C triggering solid-phase epitaxial growth (SPEG) causing further modification to the deformed nanowires. After IIB, it is observed that nanowires which had bent away from the ion beam then straighten during SPEG while those which had bent toward the ion beam bend even more. This is attributed to differences in the mechanisms responsible for the ion-beam-induced bending in opposite directions. Thus, the results reported here give insights into the mechanisms causing the IIB of nanowires and demonstrate how to predict the evolution of nanowires under irradiation and annealing. Finally, they show that, under certain conditions, the bending can even be removed via SPEG.