Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Nano Lett. 2010 Oct 13;10(10):4032-9. doi: 10.1021/nl1019722.
Progress in the synthesis of semiconductor nanowires (NWs) has prompted intensive inquiry into understanding the science of their growth mechanisms and ultimately the technological applications they promise. We present new results for the size-dependent growth kinetics of Ge NWs and correlate the results with a direct experimental measurement of the Gibbs-Thomson effect, a measured increase in the Ge solute concentration in liquid Au-Ge droplets with decreasing diameter. This nanoscale-dependent effect emerges in vapor-liquid-solid Ge NW growth and leads to a decrease in the NW growth rate for smaller diameter NWs under a wide range of growth conditions with a cutoff in growth at sufficiently small sizes. These effects are described quantitatively by an analytical model based on the Gibbs-Thomson effect. A comprehensive treatment is provided and shown to be consistent with experiment for the effect of NW growth time, temperature, pressure, and doping on the supersaturation of Ge in Au, which determines the growth rate and critical cutoff diameter for NW growth. These results support the universal applicability of the Gibbs-Thomson effect to sub-100 nm diameter semiconductor NW growth.
半导体纳米线（NWs）的合成进展促使人们深入研究其生长机制的科学原理，并最终探索其潜在的技术应用。我们提出了关于锗 NWs 尺寸相关生长动力学的新结果，并将结果与吉布斯-汤姆逊效应的直接实验测量相关联，该效应是指随着直径的减小，液态 Au-Ge 液滴中的锗溶质浓度增加。这种纳米尺度相关的效应出现在汽-液-固锗 NW 生长中，并导致在广泛的生长条件下，对于较小直径的 NW，生长速率下降，而在足够小的尺寸下，生长会中断。这些效应通过基于吉布斯-汤姆逊效应的分析模型进行定量描述。我们提供了一个全面的处理方法，并证明了它与实验结果的一致性，实验涉及到 NW 生长时间、温度、压力和掺杂对 Au 中 Ge 过饱和度的影响，而过饱和度决定了 Ge 的生长速率和临界截止直径。这些结果支持吉布斯-汤姆逊效应在亚 100nm 直径半导体 NW 生长中的普遍适用性。
