Surface-enhanced Raman spectroscopy (SERS) has been applied in many analytical fields owing to its features like single molecule sensitivity and fingerprint identification. To face the challenges in detecting large molecules, developing gap-free SERS substrates with excellent performance as well as desired electromagnetic (EM) field distribution is receiving increasing attentions. Herein, we propose a highly uniform gap-free SERS substrate consisting of Au nanodisk array / Si nanopillar spacer / Au nanohole array. The mode-hybridization between optical cavity mode and SPR mode can be simply and effectively controlled by tuning the cavity height, then the enhanced EM field can be optimized to the top surface, which is more available for analytes. Simultaneously, the decay channels were also manipulated to reduce the heat effect (with a decrease of around 10℃) of non-radiative decay during SERS measurement. Such a SERS substrate shows a great performance with the average enhancement factor of 6×10⁶ as well as a high uniformity (with a relative standard deviation of 8.5 %). This work provides new opportunities for the design and applications of gap-free SERS substrates.

中文翻译：

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无间隙杂交等离子体，具有可调谐衰变通道，用于表面增强拉曼光谱


表面增强拉曼光谱 （SERS） 因其单分子灵敏度和指纹识别等特点而被应用于许多分析领域。为了应对检测大分子的挑战，开发具有优异性能和所需电磁 （EM） 场分布的无间隙 SERS 衬底正受到越来越多的关注。在此，我们提出了一种高度均匀的无间隙 SERS 衬底，由 Au 纳米盘阵列 / Si 纳米柱间隔圈 / Au 纳米孔阵列组成。通过调整腔体高度，可以简单有效地控制光腔模式和 SPR 模式之间的模式混合，然后可以将增强的电磁场优化到顶面，从而更容易用于分析物。同时，还操纵了衰减通道以减少 SERS 测量过程中非辐射衰减的热效应（降低约 10°C）。这种 SERS 衬底表现出优异的性能，平均增强因子为 6×10⁶，并且均匀性高（相对标准偏差为 8.5%）。这项工作为无间隙 SERS 衬底的设计和应用提供了新的机会。