Silver (Ag) nanostructures demonstrate outstanding optical, electrical, magnetic, and catalytic properties and are utilized in photonic, energy, sensors, and biomedical devices. The target application and the performance can be inherently tuned by control of configuration, shape, and size of Ag nanostructures. In this work, we demonstrate the systematical fabrication of various configurations of Ag nanostructures on sapphire (0001) by controlling the Ag deposition thickness at different annealing environments in a plasma ion coater. In particular, the evolution of Ag particles (between 2 and 20 nm), irregular nanoclusters (between 30 and 60 nm), and nanocluster networks (between 80 and 200 nm) are found be depended on the thickness of Ag thin film. The results were systematically analyzed and explained based on the solid-state dewetting, surface diffusion, Volmer-Weber growth model, coalescence, and surface energy minimization mechanism. The growth behavior of Ag nanostructures is remarkably differentiated at higher annealing temperature (750 °C) due to the sublimation and temperature-dependent characteristic of dewetting process. In addition, Raman and reflectance spectra analyses reveal that optical properties of Ag nanostructures depend on their morphology.

中文翻译：

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蓝宝石上的各种银纳米结构，采用等离子自组装和薄膜反润湿。

银（Ag）纳米结构具有出色的光学，电，磁和催化特性，并被用于光子，能源，传感器和生物医学设备中。目标应用和性能可以通过控制Ag纳米结构的形状，形状和大小进行内在的调节。在这项工作中，我们通过在等离子离子镀膜机中控制不同退火环境下的Ag沉积厚度，证明了在蓝宝石（0001）上系统地构造Ag纳米结构的各种配置。特别地，发现Ag颗粒（2至20nm之间），不规则的纳米团簇（30至60nm之间）和纳米团簇网络（80至200nm之间）的演变取决于Ag薄膜的厚度。根据固态去湿对结果进行了系统的分析和解释，表面扩散，Volmer-Weber生长模型，聚结和表面能最小化机理。由于去湿过程的升华和与温度有关的特性，在较高的退火温度（750°C）下，Ag纳米结构的生长行为显着不同。此外，拉曼光谱和反射光谱分析表明，银纳米结构的光学性质取决于其形态。