Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 45: Photovoltaics: Silicon-based Systems I
HL 45.6: Vortrag
Mittwoch, 28. März 2012, 10:45–11:00, ER 270
Black silicon passivation by conformal thermal ALD deposited Al2O3 coatings — •Martin Otto1, Matthias Kroll2, Thomas Käsebier2, Roland Salzer3, and Ralf B. Wehrspohn1,3 — 1Martin-Luther-University Halle-Wittenberg, µMD Group - Institute of Physics, Halle, Germany — 2Friedrich Schiller University Jena, Institute of Applied Physics, Jena, Germany — 3Fraunhofer Institute for Mechanics of Materials Halle, Halle, Germany
Upon inductive coupled plasma reactive ion etching (ICP-RIE) of Si surfaces needle-like nanostructures with aspect ratios up to 10 emerge showing excellent anti-reflection and light-trapping properties with absorption over 97% throughout the UV and VIS spectral range. In addition, the absorption at the band edge of silicon is enormously enhanced due to scattering. In this work we report on the feasibility to deposit conformal Al2O3 dielectric layers on these very rough silicon surfaces which enable adequate surface passivation. Lifetimes over 170 µs have been measured on deep structured b-Si substrates. The optical properties of black silicon (b-Si) and the possible influence of applied alumina passivation layers as well as their passivation performance are discussed.