Large‐Scale Sub‐1‐nm Random Gaps Approaching the Quantum Upper Limit for Quantitative Chemical Sensing
Large‐Scale Sub‐1‐nm Random Gaps Approaching the Quantum Upper Limit for Quantitative Chemical Sensing
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DOI：
10.1002/adom.202001634
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发表时间：
2020-10
影响因子：
9
通讯作者：
Nan Zhang;Hai-feng Hu;Matthew H. Singer;Kuang-Hui Li;Lyu Zhou;B. Ooi;Qiaoqiang Gan
中科院分区：
文献类型：
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作者：
Nan Zhang;Hai-feng Hu;Matthew H. Singer;Kuang-Hui Li;Lyu Zhou;B. Ooi;Qiaoqiang Gan
具有纳米间隙特征的金属纳米结构可以将电磁场限制在极小的体积内。特别是，当间隙尺寸缩小到亚纳米范围时，局域场增强的量子效应揭示了光-物质相互作用的最终能力。虽然已经报道了接近量子上限的增强因子，但表面增强振动光谱传感的最大挑战仍然是固有的随机性，防止大面积均匀分布的局部场。本文报道了一种由原子层沉积和自组装单层工艺定义的具有精确控制纳米间隙的高密度随机金属纳米图案的制造策略。当间隙尺寸接近≈0.78 nm的量子态时，基于在22 mm × 60 mm大面积上相对标准偏差为4.3%的创纪录的高均匀性，证明了其定量传感的潜力。这种优越的特性为使用接近量子极限的纳米间隙结构实现更经济实惠的定量传感铺平了道路。
Metallic nanostructures with nanogap features can confine electromagnetic fields into extremely small volumes. In particular, as the gap size is scaled down to sub‐nanometer regime, the quantum effects for localized field enhancement reveal the ultimate capability for light–matter interaction. Although the enhancement factor approaching the quantum upper limit has been reported, the grand challenge for surface‐enhanced vibrational spectroscopic sensing remains in the inherent randomness, preventing uniformly distributed localized fields over large areas. Herein, a strategy to fabricate high‐density random metallic nanopatterns with accurately controlled nanogaps, defined by atomic‐layer‐deposition and self‐assembled‐monolayer processes, is reported. As the gap size approaches the quantum regime of ≈0.78 nm, its potential for quantitative sensing, based on a record‐high uniformity with the relative standard deviation of 4.3% over a large area of 22 mm × 60 mm, is demonstrated. This superior feature paves the way towards more affordable and quantitative sensing using quantum‐limit‐approaching nanogap structures.