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DF: Fachverband Dielektrische Festkörper

DF 13: Applications of dielectric solids

DF 13.2: Talk

Wednesday, April 2, 2014, 12:10–12:30, GER 37

Ultra-thin Al₂O₃ passivation layers for solar cell applications — •Andreas Nägelein¹, Christian Koppka¹, Katja Tonisch¹, and Thomas Hannappel^1,2 — ¹TU Ilmenau, Institut für Physik, Fachgebiet Photovoltaik — ²CiS Forschungsinstitut für Mikrosensorik und Photovoltaik, Erfurt

Thin Al₂O₃-layers have been shown to provide a high quality passivation on p-type surfaces. Especially for nanowire-solar cells surface-passivation plays a major role.
In order to investigate the quality of Al₂O₃ produced by atomic layer deposition (ALD) in an MOCVD reactor, p-type silicon (1-5 Ωcm) samples were coated on both sides with three different Al₂O₃ layer thicknesses (10 nm, 20 nm and 30 nm). UV/VIS measurements were done to determine the optical properties. XPS and FTIR investigations showed the composition of the layers. Passivation quality was proofed by QSSPC and MWPCD. Optical properties were measured by UV/VIS and obtained a transmission of more than 95% over a large wavelength range. QSSPC lifetime measurements showed a maximum lifetime of 388 µs at 30 nm Al₂O₃. After annealing 30 minutes at 400^∘C the lifetime increased to 1.25 ms. Comparable results are expected for nanowire applications.