Presentation Details
| The Native Oxide Growth on Polycrystalline CdSeTe/CdTe Surface and Its Impact on Device Performance (yes) Sushmakanth Myneni, Mayank Mate, Amit Munshi, Walajabad Sampath. Colorado State University, Fort Collins, CO, USA |
Abstract
Ambient air exposure between the absorber and back contact deposition was varied to control the native oxide formation on CdTe surface. A short air exposure period (~ 30 min) led to an improvement in open-circuit voltage (Voc) by 60 mV as compared to the device with minimal ambient air exposure, and enabled power conversion efficiency (PCE) reaching > 17.5 % in devices with no intentional doping (undoped). In contrast, 1 day exposure resulted in a kink in the JV, indicating a barrier formation. X-ray Photoelectron Spectroscopy (XPS) analysis verified a native oxide formation on the absorber surface. One month air exposure post acid etch did not exhibit an s-kink in the JV but severe kink was observed for unetched surface exposed under identical conditions. Notably, XPS analysis indicating an oxide layer on etched as well as unetched surface. This indicated that nature of the oxides formed on these surfaces may not be identical. Since acid etching is known to leave a Te rich surface on CdTe, it is likely TeOx that forms on acid etched surface, while mixed oxide (CdTeOx) on unetched surface.
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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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