Herein, we report an efficient method to produce silver (Ag) nanoparticle-decorated silicon (Si) nanowire (NW) arrays on a pyramidal Si (P-Si) substrate by using a pure chemical method and rapid thermal annealing in different atmospheres. A metal-assisted chemical etching technique was used to produce vertical Si NW arrays on pyramidal Si. The etching was observed to be heavily dependent on the substrate type. On planar Si (100), the etching was observed to occur in a uniform manner. However, the etching rate was observed to increase from the top to the base of the Si pyramid. The Si NWs produced from P-Si have zig-zag sidewalls as observed from high-resolution transmission electron microscopy images. However, for the same oxidant concentration, Si NWs produced from planar Si (100) consist of straight and amorphous sidewalls. Local variation of oxidant concentration is responsible for the formation of different sidewalls. The substrates are both surface-enhanced Raman scattering (SERS) active and hydrophobic. The hydrophobicity is due to the dual scale of roughness contributed to by both pyramidal and NW structures. Finite-difference time-domain simulation shows that the gap between two Ag spheres and also the gap between Si NWs and Ag spheres contributed to SERS enhancement.

中文翻译：

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硅衬底上金属纳米颗粒装饰的硅纳米线阵列及其应用

在这里，我们报告了一种有效的方法，通过使用纯化学方法和不同气氛中的快速热退火，在锥体硅 (P-Si) 衬底上生产银 (Ag) 纳米颗粒装饰的硅 (Si) 纳米线 (NW) 阵列。使用金属辅助化学蚀刻技术在金字塔形硅上生产垂直硅 NW 阵列。观察到蚀刻在很大程度上取决于基板类型。在平面Si(100)上，观察到蚀刻以均匀的方式发生。然而，观察到蚀刻速率从硅金字塔的顶部到底部增加。从高分辨率透射电子显微镜图像中观察到，由 P-Si 生产的 Si NW 具有锯齿形侧壁。然而，对于相同的氧化剂浓度，由平面硅（100）产生的硅纳米线由直的和非晶的侧壁组成。氧化剂浓度的局部变化是形成不同侧壁的原因。基材既具有表面增强拉曼散射 (SERS) 活性又具有疏水性。疏水性是由于锥体结构和 NW 结构造成的双重粗糙度。有限差分时域模拟表明，两个 Ag 球之间的间隙以及 Si NW 和 Ag 球之间的间隙有助于 SERS 增强。