Presentation Details
| MOVPE Growth of AlxGa1-xAs with Deposition Rates up to 55 μm/h for III-V Multi-Junction Solar Cells (yes) Christoph Klein, Robin Lang, Jens Ohlmann, Jonas Schoen, Frank Dimroth, David Lackner. Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany |
Abstract
We investigate high growth rate metalorganic vapor phase epitaxy of AlxGa1-xAs for indium‑free, high‑efficiency III–V tandem solar cells with improved throughput and cost competitiveness. AlxGa1-xAs offers a tunable direct bandgap (1.42 – 1.9 eV) and compatibility with growth on GaAs or Ge substrates. Using a close‑coupled showerhead reactor, we demonstrate AlxGa1-xAs growth rates up to 55 µm/h, while maintaining constant surface morphology and aluminum incorporation. Secondary ion mass spectrometry shows a non‑linear dependence of carbon and oxygen background impurities on growth rate. Time‑resolved photoluminescence on Al0.30Ga0.70As (EG = 1.8 eV) double‑heterostructures grown at 36 µm/h with a V/III ratio of 20 yield effective minority carrier lifetimes up to 12 ns. Based on these findings, we propose an Al0.30Ga0.70As/GaAs dual-junction solar cell enabling sub‑minute growth duration per subcell absorber, indicating a promising route toward high‑throughput, low cost, high‑efficiency III–V photovoltaics.
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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.