A study of nanoellipsoids for thin-film plasmonic solar cell applications

Metal nanoparticles (MNPs) support surface plasmon modes, which are used to couple light into the underlying optical modes of a semiconductor. In this paper, we investigate the suitability of localized surface plasmons to enhance the scattering efficiency of incident light from a silver nanoellipsoid and hence its absorption into silicon solar cells. Light scattering efficiency of the silver nanoellipsoid was calculated based on a quasi-static approximation. We found that the silver nanoellipsoid may be tuned to have higher scattering efficiency in the near infrared region. In this work the particle size, shape, aspect ratio and the distance of the nanoellipsoid from the substrate were varied to study their impact on light trapping in solar cells. We found that the nanoellipsoid (oblate) is more suitable to tune the resonance near the band gap of silicon as compared with a nanosphere. Calculations show that the desired resonance (around 1000 nm) can be achieved with aspect ratio lying in the domain 0.3-0.4 with a particle size of 15 nm and distance between substrate and nanoellipsoid of around 2-3 nm.