Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 55: Photovoltaics: mainly Technology and Photon Management
HL 55.4: Talk
Wednesday, March 16, 2011, 15:15–15:30, FOE Anorg
Silver nanoparticles for enhanced light absorption in thin film amorphous silicon solar cells — •Florian Lükermann1, Frank Hamelmann2, Helmut Stiebig2, and Ulrich Heinzmann1 — 1Molecular and Surface Physics, Bielefeld University, 33615 Bielefeld, Germany — 2Malibu GmbH & Co. KG, 33609 Bielefeld, Germany
Illuminating metal nanoparticles (NPs) with electromagnetic radiation leads to collective dipolar oscillations of the conduction electrons. Depending on the size, shape and surrounding material strong wavelength dependent resonances in the absorption and scattering spectra are the consequence. This so called localized surface plasmon (LSP) resonances go along with an enhanced electromagnetic field inside and in the close proximity of the NPs.
We fabricated silver NPs by thermal evaporation respectively sputtering of silver to gain thin metallic films in the range of a few nm. These films are subsequently annealed at temperatures in the order of 150 ∘C which leads to the formation of nanosized silver islands from a few nm to approximately 50 nm average diameter, depending on the film thickness. The nanoparticle films are incorporated in direct contact to the active layer of photosensitive amorphous silicon (a-Si) devices to investigate the influence of the enhanced electromagnetic field on the generation of photoexcited charge carriers.
External quantum efficiency measurements demonstrate an enhanced photocurrent in the near infrared region where a-Si in general shows no absorption. MIE simulations indicate that this effect can be associated to the LSP resonances of the incorporated NPs.