Plasmonic photovoltaics: near-field of a metal nanowire array on the interface for solar cell efficiency enhancement

• Published in: Semiconductor science and technology 2013-05, Vol.28 (5), p.55013
• Main Authors: Dmitruk, N L, Korovin, A V
• Format: Article
• Language: English
• Subjects: Applied sciences; Energy; Exact sciences and technology; III-V semiconductors; interface; nanoparticles; nanowires; Natural energy; photoelectric properties; Photovoltaic conversion; plasmonic photovoltaics; silicon; solar cell efficiency; Solar cells. Photoelectrochemical cells; Solar energy; thin film solar cell
• ISSN: 0268-1242; 1361-6641
• DOI: 10.1088/0268-1242/28/5/055013

The analysis of the main principles of plasmonic photovoltaics relative to the enhancement of the efficiency of solar cells (SCs) by means of light trapping in a thin film SC is considered in this paper. Theoretical analysis and corresponding numerical calculations of the transmittance into a semiconductor base enhancement due to light trapping via the excitation of local (surface) plasmons and surface plasmon polaritons in a periodic metal nanowire array have been performed. The calculations have been performed for rectangular cross-section metal nanowires by the differential formalism method using the covariant form of Maxwell's equations in a curvilinear coordinate system. Local distributions of the electric field in plasmonic nanostructures are calculated for metal nanowires in both s- and p-polarization of incident light. Then both the light transmittance in the near- and far-field (wave) zones and the local generation rate of electron-hole pairs have been calculated using the spatial distribution of the Poynting vector. Angular/spectral distributions of transmittance and position/spectral distributions of the generation rate in the near-field zone have complicated the non-homogeneous character due to the excitation of surface plasmons and surface plasmon polaritons. It has been shown that the main highly enhanced near-field generation is localized in the so-called hot points on the nanoparticles/nanowires surface. The planar-averaged generation rate for the p-polarization of light has a near-field component, which is always more for a Si base (indirect bandgap semiconductor) than for GaAs (direct bandgap one). This plasmonic effect can be used for the base thicknesses down up to 100-150 nm due to light scattering and the surface plasmon enhancement of near-fields. These plasmon-carrying metal nanowires can be used as a current grid in an SC too.