Abstract

The reflectance spectra of Ag layers on a silicon substrate are interpreted using the approach based on the calculation of the reflectance R_calc spectra of a thin film with variable thickness, which makes it possible to follow the effect of c-Si substrate critical points in the Brillouin zone and the formation of characteristics of bulk Ag at the edge of interband transitions. The calculated R_calc spectra were compared with the experimental R_exp spectra of the Ag nanoparticle layers with different morphologies measured at the normal and oblique (45°) angle of incidence of light. For a layer consisting of coarser nanoparticles, one can observe a steep dip in the R_exp spectrum, which almost coincides with the edge of the interband transitions in bulk Ag in the UV range, and a broad dip in the R_exp spectrum with a minimum at λ = 382 nm, which demonstrates the maximum absorption of the localized plasmon resonance of Ag nanoparticles. For the samples consisting of finer particles, the dip of the interband transitions in the R_exp spectra is not observed at both angles of incidence, since the deposited Ag nanoparticles did not form a structure with the optical properties of bulk Ag, but the bulk plasmon resonance appeared at λ ~ 335 nm in the longitudinal mode at the oblique angle of incidence.

中文翻译：

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从AgNO 3沉积到硅表面上的银纳米颗粒层的反射光谱中的光学和等离子特征的研究

摘要

使用基于可变厚度薄膜的反射率R _calc光谱计算的方法来解释硅基板上Ag层的反射光谱，这使得可以在薄膜中跟踪c-Si基板临界点的影响。布里渊区和带间跃迁边缘的块状银的特征形成。将计算出的R _calc光谱与具有不同形态的Ag纳米粒子层的实验R _exp光谱进行比较，这些纳米形态在法向和倾斜（45°）入射角下测量。对于由较粗的纳米颗粒组成的层，可以观察到R _exp的陡峭下降光谱，几乎与紫外线中的大量Ag的带间跃迁边缘重合，并且在R _exp光谱中有一个较宽的下降，在λ= 382 nm处具有最小值，这表明了Ag的局部等离激元共振的最大吸收纳米粒子。对于由较细颗粒组成的样品，在两个入射角均未观察到R _exp谱中的带间跃迁的倾角，因为沉积的Ag纳米颗粒并未形成具有块状Ag光学性质的结构，而是块状等离激元在倾斜入射角的纵向模式中，共振在λ〜335 nm处出现。