Presentation Details
| Advances in Engineered Ge Substrates for Multijunction Solar Cell Manufacturing Alexandre Chapotot1, Rajiv Sharma1, Priyanka Proost1, Robin Vanuytven1, Aitana Cano2, Rubén Fortín2, Iván García2, Daniel F.Reyes3, Veronica Braza3, Kristof Dessein1, Jinyoun Cho1. 1Umicore Electro-Optic Materials, Olen, Belgium.2Instituto de Energía Solar, E.T.S.I Telecomunicación, Universidad Politécnica de Madrid, Madrid, Spain.3Instituto de Microscopía Electrónica y Materiales (IMEYMAT), Cadiz, Spain |
Abstract
The rapid expansion of satellite constellations is accelerating the demand for high‑efficiency, lightweight, and scalable space solar power technologies. Engineered germanium (Eng. Ge) substrates have emerged as a compelling alternative to conventional bulk Ge wafers thanks to their potential for low‑cost manufacturing, reduced material use, and compatibility with flexible solar array concepts. Their thin, detachable Ge membranes enable high‑volume production pathways while maintaining the performance requirements of modern multijunction solar cells (MJSCs). This work presents Umicore’s latest advancements in Eng. Ge substrate engineering for next‑generation III–V solar cell manufacturing. By optimizing the bi‑porous Ge architecture and improving control of the as‑porosified and as‑annealed structures, we obtained a more uniform and well‑defined Eng. Ge structure, resulting in significantly reduced residual stress within the overgrown III–V layers. Further refinement of the epitaxial nucleation stack led to an order‑of‑magnitude reduction in stacking fault density, enabling more uniform device behavior and improved electrical performance. Single‑junction InGaP solar cells grown on the optimized Eng. Ge substrates achieve performance levels comparable to bulk‑Ge‑based references, with no measurable efficiency penalty. These results highlight the strong potential of Eng. Ge substrates as a pathway toward cost‑effective, sustainable, and flexible III–V solar cell technologies tailored for the evolving needs of the space sector.
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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.