Silicon (Si) and silicon–germanium (Si_xGe_1−x) nanowires (NWs) were grown out-of-plane by molecular beam epitaxy using gold (Au) as a solvent. For this purpose, a thin film of gold was deposited onto a heated substrate, resulting in the formation of droplets with a characteristic size distribution dependent on temperature. The amount, yield and NW diameter were estimated by the individual size of Au droplets and their number per area. Due to increased surface diffusion velocity with raising temperature, the droplet diameter distribution shifted from a positive skewed distribution with a high fraction of smaller droplets to a negative skewed distribution with a high fraction of larger droplets. Therefore, the distribution function for Ostwald ripening can only be applied at a temperature above 550 °C. Below 550 °C, the gamma distribution function correlates with the droplet diameter distributions. The temperature dependency of the most probable droplet diameter and the number of Au droplets per area has been determined in the inspected temperature range and can be applied for the MBE growth of Si and Si_xGe_1−x NWs. During the Si_xGe_1−x NW formation, the Au surface diffusion velocity increased, due to the epitaxial layer formation on the substrate. Therefore, the most frequently observed diameter of Si and Si_xGe_1−x NWs shifted compared to the previously formed Au droplet diameter with the highest probability, while the number of Au droplets per area decreased by a constant factor due to an increase of the contact angle. The specific diameter range for successful NW formation is reduced by incorporation of Ge into Si_xGe_1−x NWs.

中文翻译：

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通过分子束外延研究SixGe1-x纳米线的Au液滴形成和生长

硅（Si）和硅锗（Si _x Ge _{1- x}使用金（Au）作为溶剂通过分子束外延在平面外生长纳米线（NWs）。为此，将金的薄膜沉积到加热的基材上，从而形成具有取决于温度的特征尺寸分布的液滴。数量，产量和净重直径通过Au液滴的单个尺寸及其每单位面积的数量来估算。由于随着温度升高表面扩散速度增加，液滴直径分布从具有较高分数的较小液滴的正偏斜分布转变为具有较高分数的较大液滴的负偏斜分布。因此，奥斯特瓦尔德熟化的分布函数只能在高于550°C的温度下应用。低于550°C，伽马分布函数与液滴直径分布相关。在检查的温度范围内确定了最可能的液滴直径与单位面积Au液滴数的温度相关性，可用于Si和Si的MBE生长_x Ge _{1- x} NW。在Si _x Ge _{1- x} NW形成期间，由于在衬底上形成外延层，Au表面扩散速度增加。因此，与先前形成的Au液滴直径相比，最常观察到的Si和Si _x Ge _{1- x} NWs的直径发生偏移的可能性最高，而每单位面积的Au液滴数由于常数的增加而减少了一个恒定因子。接触角。通过将Ge结合到Si _x Ge _{1- x} NWs中，减小了成功形成NW的特定直径范围。