Surface plasmon effects in the absorption enhancements of amorphous silicon solar cells with periodical metal nanowall and nanopillar structures

Abstract

The authors numerically investigate the absorption enhancement of an amorphous Si solar cell, in which a periodical one-dimensional nanowall or two-dimensional nanopillar structure of the Ag back-reflector is fabricated such that a dome-shaped grating geometry is formed after Si deposition and indium-tin-oxide coating. In this investigation, the effects of surface plasmon (SP) interaction in such a metal nanostructure are of major concern. Absorption enhancement in most of the solar spectral range of significant amorphous Si absorption (320-800 nm) is observed in a grating solar cell. In the short-wavelength range of high amorphous Si absorption, the weakly wavelength-dependent absorption enhancement is mainly caused by the broadband anti-reflection effect, which is produced through the surface nano-grating structures. In the long-wavelength range of diminishing amorphous Si absorption, the highly wavelength-sensitive absorption enhancement is mainly caused by Fabry-Perot resonance and SP interaction. The SP interaction includes the contributions of surface plasmon polariton and localized surface plasmon.

Light management through guided-mode resonances in thin-film silicon solar cells

“…Numerous studies have been conducted to improve light-capture and collection efficiency of thin absorbing layers. The application of diffractive optics, [4][5][6] random texturing, 7,8 antireflective layers, 9,10 plasmonics, [11][12][13] photonic crystals, [14][15][16] guided-mode excitation, 6,17,18 and three-dimensional structures like nanowire, nanodome, and nanocone solar cells [19][20][21] shows distinguished improvements in solar absorption. Though each mechanism contributes to the manipulation of optical path lengths inside the films, the most efficient light-harvesting scheme is yet to be convincingly identified.…”

Design of nano-pattern reflectors for thin-film solar cells based on three-dimensional optical and electrical modeling

“…However, the thicker absorption layer usually increases the nonradiative recombination rates and reduces the carrier collection efficiency. Therefore, several light trapping geometries such as gratings, 1-3 nanoholes, 4-7 nanoparticles, [8][9][10][11][12][13][14] nanodomes, 15,16 and random textures [17][18][19] have been demonstrated to enhance the absorption of the solar spectrum with a thinner semiconductor layer. By incorporating the nanopattern directly into the back contact of the cell, the back textured geometry will scatter light in the longer wavelength range of the spectrum and couple incompletely absorbed light into waveguide modes of the structure.…”

Fabrication and characterization of well-aligned plasmonic nanopillars with ultrasmall separations

“…Either surface plasmon polaritons (SPPs) or localized surface plasmon resonances (LSPRs) reveal salient resonance features, and the optical properties of metal nanopillars are mainly determined by their shape, size, and even the dielectric environment. Recently, the fascinating optical properties of small nanopillars/particles [30-34] and other different geometries [35-40] have been extensively investigated both experimentally and theoretically, providing a new pathway for manipulating light at the subwavelength scale.…”