The concept of amorphous (a-Si:H)/microcrystalline (μc-Si:H) silicon tandem solar cells offers the potential for high-efficiency and low fabrication costs. Because of the small diffusion length of the generated electron-hole pairs in a-Si:H, the absorber thickness is limited to a few hundred nms. Therefore, photons at longer wavelengths are only poorly absorbed in the a-Si:H layer. Concepts for photon management are required to increase the absorption in the a-Si:H cell: the incorporation of an intermediate reflective layer (IRL) between the a-Si:H and μc-Si:H cells in combination with texturing can provide efficient light manipulation. The scattering occurs when the wavelength corresponds to the feature size of the texture, and a difficulty arises from the wide spectral range of absorption of the tandem cells (350-1100 nm). Our approach is to make use of the localized electro-magnetic field amplification that occurs in the vicinity of a metal surface through the eτ_citation of localized surface plasmons, which are resonantly coupled to metallic nanoparticles (NPs). Here the light scattering is investigated from arrays of copper NPs in order to determine design principles forplasmon-enhanced particle light trapping. To enhance forward scattering towards the μc-Si:H cell we introduce Cu NPs on the IRL dielectric ZnO layers.
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