Optimized emitter contacting on multicrystalline silicon thin film solar cells |
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Authors: | A Gawlik I Höger J Bergmann J Plentz T Schmidt F Falk G Andrä |
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Institution: | Leibniz Institute of Photonic Technology, Department Functional Interfaces, Jena, Germany |
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Abstract: | We present an optimized contacting scheme for multicrystalline silicon thin film solar cells on glass based on epitaxially crystallized emitters with a thin Al2O3 layer and a silver back reflector. In a first step a 6.5 µm thick amorphous silicon absorber layer is crystallized by a diode laser. In a second step a thin silicon emitter layer is epitaxially crystallized by an excimer laser. The emitter is covered by an Al2O3 layer with a thickness ranging from 1.0 nm to 2.5 nm, which passivates the surface and acts as a tunnel barrier. On top of the Al2O3 layer a 90–100 nm thick silver back reflector is deposited. The Al2O3 layer was found to have an optimal thickness of 1.5 nm resulting in solar cells with back reflector that achieve a maximum open‐circuit voltage of 567 mV, a short‐circuit current density of 27.9 mA/cm2, and an efficiency of 10.9%. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) |
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Keywords: | thin films solar cells silicon laser crystallization epitaxy Al2O3 |
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