Interface dynamics and crystal phase switching in GaAs nanowires.
Interface dynamics and crystal phase switching in GaAs nanowires.
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DOI：
10.1038/nature17148
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发表时间：
2016-03-17
期刊：
影响因子：
64.8
通讯作者：
Ross FM
中科院分区：
文献类型：
--
作者：
Jacobsson D;Panciera F;Tersoff J;Reuter MC;Lehmann S;Hofmann S;Dick KA;Ross FM
控制非平衡晶体结构的形成是晶体生长中最重要的挑战之一。催化生长的纳米线为研究相选择的基础物理提供了一个理想的系统，同时也为基于晶体多型工程的新型电子应用提供了潜力。在这里，我们拍摄了生长过程中的砷化镓纳米线，因为它们在不同的生长条件下在多型之间切换。我们发现多型之间的生长动力学存在显著差异，包括界面形态、阶梯流动和催化剂几何形状的差异。我们通过一个与催化剂体积、三结处的接触角和每个新层的成核位置相关的模型来解释这些差异和相选择。这使我们能够预测每个相应该优选的条件，并使用这些预测来设计GaAs异质结构。我们认为这些结果可能适用于其他纳米线系统的相位选择。
Controlled formation of non-equilibrium crystal structures is one of the most important challenges in crystal growth. Catalytically-grown nanowires provide an ideal system for studying the fundamental physics of phase selection, while also offering the potential for novel electronic applications based on crystal polytype engineering. Here we image GaAs nanowires during growth as they are switched between polytypes by varying growth conditions. We find striking differences between the growth dynamics of the polytypes, including differences in interface morphology, step flow, and catalyst geometry. We explain the differences, and the phase selection, through a model that relates the catalyst volume, contact angle at the trijunction, and nucleation site of each new layer. This allows us to predict the conditions under which each phase should be preferred, and use these predictions to design GaAs heterostructures. We suggest that these results may apply to phase selection in other nanowire systems.