Presentation Details
| First-Principles Study of Arsenic Activation and Selenium Redistribution in CdSeTe/CdTe Solar Cells Boney Mahesh1, Ali Abbas1, Pooja Goddard2, Roger Smith2, Michael Walls1. 1Centre for Renewable Energy Systems Technology (CREST), Wolfson School of Mechanical, Electrical an, Loughborough, United Kingdom.2Department of Chemistry, Loughborough University, Loughborough, United Kingdom |
Abstract
Arsenic is a promising p-type dopant for CdTe-based solar cells, but its activation efficiency remains limited. Particularly in CdSeTe/CdTe absorber where selenium is incorporated for bandgap grading. Experimental studies have reported an anti-correlative behaviour between arsenic and selenium concentrations following arsenic activation, but the understanding of this behaviour remains unclear. This study investigates this interaction using density functional theory (DFT). The relative stability of arsenic-, selenium- and tellurium- related di-interstitials (dumbbells) complexes is assessed, revealing that As-Se dumbbells are energetically more favourable than As-Te and Se-Te configurations. Interpreting these results withing the framework of the established arsenic ‘kick out’ activation mechanism in CdTe, it suggests that arsenic preferentially interacts with selenium during activation, facilitating selenium redistribution. Nudged elastic band (NEB) calculations further show that selenium has a low diffusion barrier in CdTe, enabling easy diffusion once released from lattice sites. Together, these results provide an explanation for the experimentally observed Se-As anti-correlation and improve our understanding of arsenic activation.
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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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