Choi Han-Kyu, Park Sang-Min, Jeong Jeeyoon, Lee Hankyul, Yeon Gyu Jin, Kim Dai-Sik, Kim Zee Hwan
Department of Chemistry, Seoul National University, Seoul 08826, Korea.
Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.
J Phys Chem Lett. 2022 Apr 7;13(13):2969-2975. doi: 10.1021/acs.jpclett.2c00403. Epub 2022 Mar 28.
A well-designed narrow gap between noble metal nanostructures plays a prominent role in surface-enhanced Raman scattering (SERS) to concentrate electromagnetic fields at the local point, called a "hot spot". However, SERS-active substrate fabrication remains a substantial hurdle due to the high process cost and the difficulty of engineering efficient plasmonic hot spots at the target area. In this study, we demonstrate a simple photolithographic method for generating ultrasensitive SERS hot spots at desired positions. The solid-state dewetting of a Ag thin film (thickness of ∼10 nm) using a continuous-wave laser (∼1 MW/cm) generates a closely packed assembly of hemispherical Ag nanoislands. Some of these nanoislands provide substantial plasmonic-field enhancement that is sufficient for single-molecule detection and plasmon-catalyzed chemical reaction. Such hot spot structures can be patterned on the substrate with a spatial resolution of better than 1 μm. In integrated analytical devices, the patterned SERS hot spots can be used as position-specific chemical-sensing elements.
贵金属纳米结构之间精心设计的窄间隙在表面增强拉曼散射（SERS）中起着重要作用，可将电磁场集中在局部点，即所谓的“热点”。然而，由于工艺成本高以及在目标区域设计高效等离子体热点的困难，SERS活性基底的制造仍然是一个重大障碍。在本研究中，我们展示了一种简单的光刻方法，用于在所需位置产生超灵敏的SERS热点。使用连续波激光（~1 MW/cm）对Ag薄膜（厚度约为10 nm）进行固态去湿，可产生紧密堆积的半球形Ag纳米岛组件。其中一些纳米岛提供了足够的等离子体场增强，足以用于单分子检测和等离子体催化化学反应。这种热点结构可以在基底上以优于1μm的空间分辨率进行图案化。在集成分析设备中，图案化的SERS热点可以用作特定位置的化学传感元件。
