Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA.
Nanotechnology. 2013 Mar 8;24(9):095707. doi: 10.1088/0957-4484/24/9/095707. Epub 2013 Feb 12.
Metal nanoparticles exhibit a localized surface plasmon resonance (LSPR) which is very sensitive to the size and shape of the nanoparticle and the surrounding dielectric medium. The coupling between the electromagnetic radiation and the localized surface plasmon in metallic nanoparticles results in a sizable enhancement of the incident fields, making them possible candidates for plasmonic applications. In particular, partially exposed metallic nanoparticles distributed in a dielectric matrix can provide prime locations for LSPR spectroscopy and sensing. We report the synthesis and characterization of a plasmonic substrate consisting of Ag nanoparticles partially buried in MgO. Ag nanoparticles of different shapes and size distributions were synthesized below the surface of MgO by implanting 200 keV Ag(+) ions followed by annealing at 1000 °C for 10 and 30 h. A detailed optical and structural characterization was carried out to understand the evolution of the Ag nanoparticle and size distribution inside the MgO matrix. Micro x-ray diffraction (Micro-XRD) was employed to investigate the structural properties and estimate the crystallite size. The nanoparticles evolved from a spherical to a faceted morphology with annealing time, assuming an octahedral shape truncated at the (001) planes, as visualized from aberration-corrected transmission electron microscopy (TEM) images. The nanoparticles embedded in MgO were shown to be pure metallic Ag using atom probe tomography (APT). The nanoparticles were partially exposed to the surface by employing plasma etch techniques to remove the overlaying MgO. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to study the surface morphology and obtain a height distribution for the partially exposed nanoparticles.
金属纳米粒子表现出局域表面等离子体共振（LSPR），其对纳米粒子的尺寸和形状以及周围介电介质非常敏感。电磁辐射与金属纳米粒子中的局域表面等离子体之间的耦合导致入射场的大幅度增强，使它们成为等离子体应用的候选者。特别是，部分暴露于介电基质中的金属纳米粒子可以为 LSPR 光谱学和传感提供主要位置。我们报告了由部分埋入 MgO 中的 Ag 纳米粒子组成的等离子体基底的合成和表征。通过在 MgO 表面下注入 200keV 的 Ag(+)离子，然后在 1000°C 下退火 10 和 30 小时，合成了不同形状和尺寸分布的 Ag 纳米粒子。进行了详细的光学和结构表征，以了解 Ag 纳米粒子在 MgO 基质中的演变和尺寸分布。微 X 射线衍射（Micro-XRD）用于研究结构特性并估计晶粒尺寸。纳米粒子随着退火时间从球形演变为面心形态，假设在（001）平面截断的八面体形状，从像差校正的透射电子显微镜（TEM）图像中可以看出。原子探针断层扫描（APT）显示嵌入 MgO 中的纳米粒子是纯金属 Ag。通过等离子体刻蚀技术部分暴露于表面，去除覆盖的 MgO。扫描电子显微镜（SEM）和原子力显微镜（AFM）用于研究表面形态并获得部分暴露纳米粒子的高度分布。
