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Title: A comparative study of microstructural stability and sulphur diffusion in CdS/CdTe photovoltaic devices

Abstract

The role of CdCl2 activation in the production of high quality CdTe-based photovoltaic devices remains a subject of much debate. In this study, CdTe-based cells produced in three independent laboratories using different device fabrication technologies are investigated before and after CdCl2 activation with regard to structural changes (recrystallisation and grain growth) and sulphur out-diffusion. Using scanning transmission electron microscopy (STEM) and x-ray diffraction it is demonstrated that CdCl2 activation of the investigated cells produces no statistical structural changes to the CdTe. Additionally, energy dispersive spectrometry (EDS) performed in the STEM on the same samples illustrates that the change in sulphur diffusion following activation is more limited than expected from previous studies; no change is detectable when the thermal budget for CdTe deposition is significantly greater than that for activation. This suggests that the efficiency enhancement during CdCl2 treatment is not due to sulphur out-diffusion. Lastly, cathodoluminescence microscopy is used to demonstrate in two dimensions how sulphur diffuses into a model sample and the results are found to be consistent with STEM-EDS. Some spectroscopic evidence for enhanced sulphur diffusion along grain boundaries is also observed.

Authors:
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Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1351589
Report Number(s):
NREL/JA-5K00-64674
Journal ID: ISSN 0927-0248
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article
Journal Name:
Solar Energy Materials and Solar Cells
Additional Journal Information:
Journal Volume: 141; Journal ID: ISSN 0927-0248
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; CdTe/CdS photovoltaics; sulphur diffusion; EDS; STEM; cathodoluminescence

Citation Formats

Taylor, A. A., Major, J. D., Kartopu, G., Lamb, D., Duenow, J., Dhere, R. G., Maeder, X., Irvine, S. J. C., Durose, K., and Mendis, B. G. A comparative study of microstructural stability and sulphur diffusion in CdS/CdTe photovoltaic devices. United States: N. p., 2015. Web. doi:10.1016/j.solmat.2015.06.010.
Taylor, A. A., Major, J. D., Kartopu, G., Lamb, D., Duenow, J., Dhere, R. G., Maeder, X., Irvine, S. J. C., Durose, K., & Mendis, B. G. A comparative study of microstructural stability and sulphur diffusion in CdS/CdTe photovoltaic devices. United States. doi:10.1016/j.solmat.2015.06.010.
Taylor, A. A., Major, J. D., Kartopu, G., Lamb, D., Duenow, J., Dhere, R. G., Maeder, X., Irvine, S. J. C., Durose, K., and Mendis, B. G. Thu . "A comparative study of microstructural stability and sulphur diffusion in CdS/CdTe photovoltaic devices". United States. doi:10.1016/j.solmat.2015.06.010.
@article{osti_1351589,
title = {A comparative study of microstructural stability and sulphur diffusion in CdS/CdTe photovoltaic devices},
author = {Taylor, A. A. and Major, J. D. and Kartopu, G. and Lamb, D. and Duenow, J. and Dhere, R. G. and Maeder, X. and Irvine, S. J. C. and Durose, K. and Mendis, B. G.},
abstractNote = {The role of CdCl2 activation in the production of high quality CdTe-based photovoltaic devices remains a subject of much debate. In this study, CdTe-based cells produced in three independent laboratories using different device fabrication technologies are investigated before and after CdCl2 activation with regard to structural changes (recrystallisation and grain growth) and sulphur out-diffusion. Using scanning transmission electron microscopy (STEM) and x-ray diffraction it is demonstrated that CdCl2 activation of the investigated cells produces no statistical structural changes to the CdTe. Additionally, energy dispersive spectrometry (EDS) performed in the STEM on the same samples illustrates that the change in sulphur diffusion following activation is more limited than expected from previous studies; no change is detectable when the thermal budget for CdTe deposition is significantly greater than that for activation. This suggests that the efficiency enhancement during CdCl2 treatment is not due to sulphur out-diffusion. Lastly, cathodoluminescence microscopy is used to demonstrate in two dimensions how sulphur diffuses into a model sample and the results are found to be consistent with STEM-EDS. Some spectroscopic evidence for enhanced sulphur diffusion along grain boundaries is also observed.},
doi = {10.1016/j.solmat.2015.06.010},
journal = {Solar Energy Materials and Solar Cells},
issn = {0927-0248},
number = ,
volume = 141,
place = {United States},
year = {2015},
month = {10}
}