Nanogaps in metallic nanostructures produce local field enhancements with potential applications in surface enhanced spectroscopy, solar energy conversion, and photocatalysis. Atomic layer deposition is applied as a conformal coating to modify nanogap sizes and tune the optical properties of plasmonic dimer arrays with sub-10 nm nanogaps. Nanostructures are fabricated using layers of gold and palladium to combine features of plasmonics and area-selective atomic layer deposition, where copper metal is deposited on palladium-covered surfaces. Direct measurements of optical extinction for successive smaller nanogaps and thicker copper coatings show that spectral features become broadened at first due to heating-induced shape changes but subsequently sharpen as copper coatings form on palladium structures. Furthermore, longitudinal resonances of plasmonic dimers blue shift for thin coatings due to heating and decreasing aspect ratio, but thicker coatings lead to red shifts due to narrowing nanogaps. Together, these results show that area-selective atomic layer deposition is a promising tool for achieving large area arrays of plasmonic dimers with sub-10 nm nanogaps.

中文翻译：

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通过区域选择性原子层沉积可调谐和可扩展地制造具有亚 10 nm 纳米间隙的等离子体二聚体阵列

金属纳米结构中的纳米间隙产生局部场增强，在表面增强光谱、太阳能转换和光催化方面具有潜在应用。原子层沉积用作保形涂层，以修改纳米间隙尺寸并调整具有亚 10 nm 纳米间隙的等离子体二聚体阵列的光学特性。纳米结构是使用金和钯层制造的，以结合等离子体激元和区域选择性原子层沉积的特征，其中铜金属沉积在钯覆盖的表面上。连续更小的纳米间隙和更厚的铜涂层的光学消光的直接测量表明，由于加热引起的形状变化，光谱特征首先变宽，但随后随着在钯结构上形成铜涂层而变得尖锐。此外，由于加热和降低纵横比，薄涂层的等离子体二聚体的纵向共振蓝移，但由于纳米间隙变窄，较厚的涂层导致红移。总之，这些结果表明，区域选择性原子层沉积是实现具有亚 10 nm 纳米间隙的大面积等离子体二聚体阵列的有前途的工具。