Nanophotonic light trapping in polycrystalline silicon thin-film solar cells using periodically nanoimprint-structured glass substrates

Autor: Christiane Becker, Franziska Back, Bernd Löchel, Tobias Sontheimer, Veit Preidel, Bernd Rech, Alexei Erko, Eveline Rudigier-Voigt, Philippe Wyss, Jürgen Probst, Frank Schmidt, Jolly Xavier, Sven Burger, Christoph Hülsen
Rok vydání: 2013
Předmět:
Zdroj: SPIE Proceedings.
ISSN: 0277-786X
Popis: A smart light trapping scheme is essential to tap the full potential of polycrystalline silicon (poly-Si) thin-film solar cells. Periodic nanophotonic structures are of particular interest as they allow to substantially surpass the Lambertian limit from ray optics in selected spectral ranges. We use nanoimprint-lithography for the periodic patterning of sol-gel coated glass substrates, ensuring a cost-effective, large-area production of thin-film solar cell devices. Periodic crystalline silicon nanoarchitectures are prepared on these textured substrates by high-rate silicon film evaporation, solid phase crystallization and chemical etching. Poly-Si microhole arrays in square lattice geometry with an effective thickness of about 2μm and with comparatively large pitch (2 μm) exhibit a large absorption enhancement (A900nm = 52%) compared to a planar film (A900nm ~ 7%). For the optimization of light trapping in the desired spectral region, the geometry of the nanophotonic structures with varying pitch from 600 nm to 800 nm is tailored and investigated for the cases of poly-Si nanopillar arrays of hexagonal lattice geometry, exhibiting an increase in absorption in comparison to planar film attributed to nanophotonic wave optic effects. These structures inspire the design of prospective applications such as highly-efficient nanostructured poly-Si thin-film solar cells and large-area photonic crystals.
Databáze: OpenAIRE