Presentation Details
| New Cost-Effective Nano-Structuring Technique for Light Management in III-V Thin-Film Photovoltaics Alessandra Selis1, Jenny Norberg1, 2, Nicolas Alt1, 2, Andrea Cattoni3, Oliver Hoehn1, 2. 1Fraunhofer ISE, Freiburg, Germany.2University of Freiburg, Freiburg, Germany.3University of Freiburg, Freiburg, Germany.4Politecnico di Milano, Milan, Italy.5University of Freiburg, Freiburg, Germany |
Abstract
Achieving higher radiation hardness and improved sustainability in space photovoltaics requires substrate-free architectures. GaInP/GaAs thin-film tandem solar cells are a promising solution, eliminating Ge substrates and reducing mass. Increasing the optical path length via a nanostructured back mirror enables thinning of both subcells, particularly the least radiation-tolerant GaAs subcell, thereby improving the end-of-life performance. Reliable and cost-effective fabrication of such mirrors is essential for industrial relevance. In this work, we compare three approaches for transferring a 1 µm-periodic structure to the rear side of GaInP/GaAs thin-film tandem solar cells. For pattern transfer in a III–V semiconductor layer, we compare the reliable but costly dry etching technology, the simple but less accurate wet etching, and a novel method based on electrochemical nanoimprint lithography (ECNL) adapted to a roll-to-plate setup, which combines the advantages of the two previous techniques. Preliminary results include EQE and reflection measurements for planar and nanostructured devices. While dry etching achieves the highest pattern fidelity, ECNL emerges as a low-cost alternative for structuring III-V semiconductors, eliminating vacuum processing and photolithography requirements.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.
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