Presentation Details
| Eutectic Enhanced CdCl2 Heat Treatment for Oxygen-free Processing of CdTe Solar Cells Kara B.Kile, Zulkifl Hussain, Isuru Lakmal, Kiran Lamichhane, Prabodika N.Kaluarachchi, Manoj K.Jamarkattel, Shawn M.Wolffersdorff, Aparajita Dixit, Ebin Bastola, Randy J.Ellingson, Adam B.Phillips, Michael J.Heben. Wright Center for Photovoltaics Innovation and Commercialization (PVIC), Department of Physics and A, Toledo, OH, USA |
Abstract
Group V elements are promising dopants for CdTe photovoltaics, but their strong sensitivity to oxygen necessitates tightly controlled processing environments. Effective CdCl2 heat treatment (CHT) is thought to rely on a CdCl2-O2 eutectic, motivating the exploration of an oxygen-free alternative eutectic such as CdCl2-NaCl or CdCl2-KCl. To investigate O2-free CHT, we developed a glovebox CHT system to treat evaporated CdSe/CdTe films in nitrogen using CdCl2 solutions with NaCl or KCl additives. The treatments with the additional salt leads to increased grain growth, randomization of structure orientation, and photoluminescence compared to samples treated with CdCl2 alone. Currently, all treatments in the N2 environment led to a layer of chloride residue that is strongly bound to the surface and prevent high device efficiency. We have identified several paths to eradicate this issue and do not expect this residue to prevent fabrication of high performance devices. The residue notwithstanding, these results suggest a viable O2-free CHT pathway compatible with group V doping.
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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.