Solid State Physics and NanoLund , Lund University , P.O. Box 118, Lund 22100 , Sweden.
Centre for Analysis and Synthesis , Lund University , P.O. Box 124, Lund 22100 , Sweden.
Nano Lett. 2019 Feb 13;19(2):1197-1203. doi: 10.1021/acs.nanolett.8b04637. Epub 2019 Jan 10.
Growing GaAs nanowires with well-defined crystal structures is a challenging task, but may be required for the fabrication of future devices. In terms of crystal phase selection, the connection between theory and experiment is limited, leaving experimentalists with a trial and error approach to achieve the desired crystal structures. In this work, we present a modeling approach designed to provide the missing connection, combining classical nucleation theory, stochastic simulation, and mass transport through the seed particle. The main input parameters for the model are the flows of the growth species and the temperature of the process, giving the simulations the same flexibility as experimental growth. The output of the model can also be directly compared to experimental observables, such as crystal structure of each bilayer throughout the length of the nanowire and the composition of the seed particle. The model thus enables for observed experimental trends to be directly explored theoretically. Here, we use the model to simulate nanowire growth with varying As flows, and our results match experimental trends with a good agreement. By analyzing the data from our simulation, we find theoretical explanations for these experimental results, providing new insights into how the crystal structure is affected by the experimental parameters available for growth.
生长具有明确晶体结构的 GaAs 纳米线是一项具有挑战性的任务，但对于未来器件的制造可能是必需的。在晶体相选择方面，理论与实验之间的联系有限，这使得实验人员只能通过反复试验来实现所需的晶体结构。在这项工作中，我们提出了一种建模方法，旨在提供缺失的联系，将经典成核理论、随机模拟和通过种子颗粒的质量传输结合起来。该模型的主要输入参数是生长物质的流动和过程的温度，这使得模拟具有与实验生长相同的灵活性。模型的输出也可以直接与实验可观察量进行比较，例如纳米线整个长度上每个双层的晶体结构和种子颗粒的组成。因此，该模型可以直接从理论上探索观察到的实验趋势。在这里，我们使用该模型模拟了具有不同 As 流量的纳米线生长，我们的结果与实验趋势吻合得很好。通过分析我们模拟的数据，我们找到了这些实验结果的理论解释，为晶体结构如何受实验可生长参数的影响提供了新的见解。
