Aluminum is a plasmonic material well known for its excellent stability, complementary metal–oxide–semiconductor compatibility and wide availability as compared to popular plasmonic materials such as gold and silver. Aluminum can support surface plasmon resonances in a broad spectral range, including the deep ultra-violet, a regime where no other plasmonic materials can work. However, conventional aluminum films suffer from high losses in the visible region and low fidelity and reproducibility in nanofabrication, making aluminum plasmonics non-ideal for applications. Herein, we report the experimental results of consistent surface plasmon propagation length measurements for epitaxially grown aluminum and silver films (epifilms), using three different methods (white light interferometry, laser scattering and spectroscopic ellipsometry) in the full visible spectrum. In order to avoid losses caused by inferior material quality, we used single-crystalline aluminum and silver films for direct comparison. We found that, on directly comparing with the silver epifilm, the aluminum epifilm possesses reasonably long plasmon propagation lengths in the full visible range and outperforms silver in the deep blue region. These results illustrate the great potential of epitaxial aluminum films for visible-spectrum plasmonic applications, resulting from their superior crystallinity and excellent surface and interface properties.

中文翻译：

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低损耗铝外延膜，可扩展且可持续的等离激元：与银外延膜的直接比较

与流行的等离子材料（例如金和银）相比，铝是一种等离子材料，以其出色的稳定性，互补的金属-氧化物-半导体兼容性和广泛的可用性而闻名。铝可以在很宽的光谱范围内支持表面等离振子共振，包括深紫外线，这是其他等离激元材料无法起作用的一种方式。然而，常规的铝膜在可见光区域遭受高损失，并且在纳米加工中具有低保真度和可再现性，这使得铝等离子体激元在应用中不理想。在此，我们报告了使用三种不同的方法（白光干涉法，外延法）对外延生长的铝和银膜（外延膜）进行一致的表面等离子体激元传播长度测量的实验结果。激光散射和椭圆偏振光谱）。为了避免由于劣质材料而造成的损失，我们使用了单晶铝和银膜进行直接比较。我们发现，与银外延膜直接比较，铝外延膜在整个可见光范围内具有相当长的等离激元传播长度，并且在深蓝色区域中表现优于银。这些结果说明了外延铝膜在可见光谱等离激元应用中的巨大潜力，这归因于其优异的结晶度以及出色的表面和界面特性。铝外延膜在整个可见光范围内具有相当长的等离激元传播长度，在深蓝色区域的性能优于银。这些结果说明了外延铝膜在可见光谱等离激元应用中的巨大潜力，这归因于其优异的结晶度以及出色的表面和界面特性。铝外延膜在整个可见光范围内具有相当长的等离激元传播长度，在深蓝色区域的性能优于银。这些结果说明了外延铝膜在可见光谱等离激元应用中的巨大潜力，这归因于其优异的结晶度以及出色的表面和界面特性。