The paper investigates the light incoupling into c-Si solar cells due to the excitation of localized surface plasmon resonances in periodic metallic nanoparticles by finite-difference time-domain (FDTD) technique. A significant enhancement of AM1.5G solar radiation transmission has been demonstrated by depositing nanoparticles of various metals on the upper surface of a semi-infinite Si substrate. Plasmonic nanostructures located close to the cell surface can scatter incident light efficiently into the cell. Al nanoparticles were found to be superior to Ag, Cu, and Au nanoparticles due to the improved transmission of light over almost the entire solar spectrum and, thus, can be a potential low-cost plasmonic metal for large-scale implementation of solar cells. 1. Introduction Solar researchers across the globe are showing a keen interest in plasmonic solar cells nowadays. It exploits the nanoscale optical property of noble metals for optical absorption enhancement resulting in an overall increase in the cell conversion efficiency [1–3]. Metallic nanostructures support localized surface plasmon resonances which are the collective oscillations of conduction electrons [2, 3]. Metal nanoparticles strongly scattered the incident light of wavelengths near their resonances, upon excitation. When located in proximity to a high-index substrate, a significant part of the scattered light is coupled into the substrate [1–3]. The resonance wavelength of the nanoparticles can be tuned throughout a broad spectral range by adjusting the size, shape, density, and dielectric properties of the surrounding medium [1–3]. Silver (Ag) and gold (Au) are the most widely used materials for plasmonic solar cells owing to their surface plasmon resonances located in the visible region [2, 3]. Other metals such as aluminium (Al) and copper (Cu) also support surface plasmons whose resonances lie in ultraviolet and visible range of solar spectrum [3]. Several research groups have demonstrated experimentally and numerically the enhancement of optical absorption in Si solar cells using plasmonic particles. Enhanced incoupling of light into semiconductor substrate by scattering from Ag nanoparticles was first recognized in 1998 and 20-fold photocurrent enhancement has been observed on 165？nm thick silicon-on-insulator (SOI) photodetectors at 800？nm wavelength from 100？nm sized Ag particles [4]. In a recent work, an enhancement by a factor of 2.3 in external quantum efficiency of thin Si solar cells at 1100？nm wavelength using Ag nanoparticles was reported [5]. An enhancement of 8.1% in
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