NanoOpto, API Technologies Corporation, Somerset, New Jersey 08873, USA.
Nano Lett. 2010 May 12;10(5):1780-6. doi: 10.1021/nl1003587.
The surface-enhanced Raman spectroscopy (SERS) activity and the optical reflectance of a subwavelength gold nanograting fabricated entirely using top down technologies on silicon wafers are presented. The grating consists of 120 nm gold cladding on top of parallel silica nanowires constituting the grating's lines, with gaps between nanowires <10 nm wide at their narrowest point. The grating produces inordinately intense SERS and shows very strong polarization dependence. Reflectance measurements for the optimized grating indicate that (when p-polarization is used and at least one of the incident electric field components lies across the grating lines) the reflectance drops to <1% at resonance, indicating that essentially all of the radiant energy falling on the surface is coupled into the grating. The SERS intensity and the reflectance at resonance anticorrelate predicatively, suggesting that reflectance measurements can provide a nondestructive, wafer-level test of SERS efficacy. The SERS performance of the gratings is very uniform and reproducible. Extensive measurements on samples cut from both the same wafer and from different wafers, produce a SERS intensity distribution function that is similar to that obtained for ordinary Raman measurements carried out at multiple locations on a polished (100) silicon wafer.
本文介绍了一种完全采用自上而下技术在硅片上制作的亚波长金纳米光栅的表面增强拉曼光谱（SERS）活性和光学反射率。该光栅由顶部的 120nm 厚金覆盖层和构成光栅线的平行二氧化硅纳米线组成，纳米线之间的间隙在最窄处小于 10nm。该光栅产生异常强烈的 SERS，并表现出很强的偏振依赖性。优化后的光栅的反射率测量表明，（当使用 p 偏振且至少一个入射电场分量跨越光栅线时）在共振时反射率降至<1%，表明基本上落在表面上的所有辐射能都被耦合到光栅中。SERS 强度和共振时的反射率呈反相关预测，表明反射率测量可以提供对 SERS 功效的非破坏性、晶圆级测试。光栅的 SERS 性能非常均匀且可重复。对从同一晶圆和不同晶圆上切割的样品进行广泛测量，产生的 SERS 强度分布函数与在（100）硅晶圆的多个位置进行普通拉曼测量得到的分布函数相似。
