Formation of metal nanoparticles tailored by dynamic oblique deposition for plasmonic applications

利用动态斜角度沉积技术，我们证明了在具有强各向异性表面形貌的模板层上直接形成具有准平行主轴的银和金纳米棒。通过改变沉积条件而无需任何预处理或后处理，可以调整纳米棒的光学性质，并且所得到的纳米棒阵列具有高表面增强拉曼散射（SERS）活性。除了大面积的宏观均匀性外，我们的纳米棒阵列还包含高密度的分离矿物。利用最佳银纳米棒阵列，成功地展示了罗丹明6G溶液微滴的SERS成像，成像的空间分辨率至少为几μm。这些特征适合生物材料的SERS成像。此外，我们通过在高温（HT-GLAD）衬底上的掠角沉积证明了不寻常的金属晶须的生长，而通常的柱状结构由于加速表面扩散而完全消失。HT-GLAD对于晶须的成核和垂直生长的晶须侧面金属原子的有效供应是必不可少的。HT-GLAD将首次揭示金属晶须蒸汽生长的机制。

Using a dynamic oblique angle deposition technique, we demonstrate the direct formation of Ag and Au nanorods with quasi-parallel major axes on a template layer of oxide having a strongly anisotropic surface morphology. The optical properties of the nanorods are tuned by varying the deposition conditions without any pre- or posttreatment, and the resulting nanorod arrays exhibit high surface-enhanced Raman scattering (SERS) activity. In addition to high macroscopic uniformity over a large area, our nanorod arrays contain a high density of isolated minerals. Using the optimum Ag nanorod arrays, the SERS imaging of the microdroplets of a rhodamine 6G solution is successfully demonstrated The space resolution of the imaging is of the order of at least a few μm. These features are suitable for the SERS imaging of biomaterials. In addition, we demonstrate the growth of unusual metal whiskers by glancing angle deposition on a high temperature (HT-GLAD) substrate, while the usual columnar structures completely disappear due to accelerated surface diffusion. HT-GLAD is essential fur the nucleation of the whiskers and efficient supply of metal atoms on the side surface of the vertically growing whiskers. HT-GLAD will, for the first time, reveal the mechanisms fm the vapor growth of metal whiskers.