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HL: Fachverband Halbleiterphysik
HL 7: Poster I
HL 7.15: Poster
Monday, March 27, 2023, 13:00–15:00, P2/EG
Structured Gradient Index Silicon (Oxy)Nitride Layers for Antireflection in Silicon Solar Cells — •Florian Damerau1, Maria Gaudig1, Ralf Wehrspohn1, Prerak Dhawan2, Carsten Rockstuhl2, and Alexander Sprafke1 — 1Institute of Physics, Martin Luther University Halle-Wittenberg, Heinrich-Damerow-Str. 4, 06120 Halle (Saale), Germany — 2Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
The frontside of crystalline silicon (c-Si) solar cells oftentimes is micro- or nanotextured to increase light in-coupling, and thus conversion efficiency. Current state-of-the-art textures comprise micron sized pyramidal structures, whereas future ultrathin c-Si solar cells demand new approaches such as submicron nanophotonic structures. However, directly nanotexturing the Si surface degrades its electronic properties strongly, such that a possible gain in absorption does not necessarily translate into an increased conversion efficiency. In this work, we aim to maintain the electronic properties of a planar c-Si interface by leaving it intact but place a nanophotonic structure on top. This structure consists of a nanstructured SiOxNy layer. Moreover, changing the stoichiometry (x,y) during deposition enables us to smoothly vary its refractive index between n≈ 1.5−3.0. Inspired by transformation optics, we aim to mimic the optical properties of strongly non-planar textures such as black silicon by a planar layer of smoothly varying spatial-dependant refractive index. In this contribution we will present experimental results on the microstructure as well as on the optical properties of our fabricated structures.