Enhancement of light absorption using high-k dielectric in localized surface plasmon resonance for silicon-based thin film solar cells

摘要

The application of high-dielectric-constant (k) materials, e.g., Si_3N_4, ZrO_2, and HfO_2, to localized surface plasmon resonance (LSPR) excited by a Au nanoparticle structure has been investigated and simulated for the enhancement of light absorption in Si-based thin film solar cells by using Mie theory and three-dimensional finite-difference time-domain computational simulations. As compared to a conventional SiO_2 dielectric spacing layer, the high-k dielectrics have significant advantages, such as (ⅰ) a polarizability over two times higher, (ⅱ) an extinction cross-section 4.1 times larger, (ⅲ) a 5.6% higher transmission coefficient, (ⅳ) a maximal 39.9% and average 25.0% increase in the transmission of the electromagnetic field, (ⅴ) an absorption of the transmitted electromagnetic field that is a maximum of 2.8 times and an average of 1.4 times greater, and (ⅵ) increased absorption efficiency and extended cover range. Experimental results show that the average absorptance in the visible spectrum using high-k enhanced LSPR was maximally 31.1% higher than that using SiO_2, demonstrating that the high-k dielectrics can be used as a potential spacing layer for light absorption in Au nanoparticle excited LSPR in Si-based thin film solar cells.