Degradation of Mg-doped zinc oxide buffer layers in thin film CdTe solar cells
Abstract
Cadmium Sulphide is the conventional n-type buffer layer used in thin film Cadmium Telluride solar cells. It is well known that Cadmium Sulphide causes optical losses and sulphur diffuses into the absorber during high temperature activation. Sputter-deposited Mg-doped ZnO (MZO) has been shown to be an attractive buffer layer for Cadmium Telluride solar cells due to its transparency and tuneable band gap. It is also stable to high temperature processing and avoids diffusion of elements into the cadmium telluride absorber during the cadmium chloride activation treatment. However, degradation is observed in solar cells incorporating MZO buffer layers. Analysis of the MZO film surface potential has revealed significant fluctuations in the thin film work function once the layer is exposed to the atmosphere following deposition. These fluctuations are attributed to the high reactivity to water vapour of the MgO contained in the MZO films. This has been analysed using X-ray Photoelectron Spectroscopy to determine corresponding changes in the surface chemistry. The Zinc Oxide component is relatively stable, but the analysis shows that MgO forms a Mg(OH)2 layer on the MZO surface which forms a secondary barrier at the MZO/CdTe interface and/or at the interface between MZO and the Fluorine-doped SnO2. Thismore »
- Authors:
-
- Loughborough Univ., Loughborough, Leicestershire (United Kingdom)
- Colorado State Univ., Fort Collins, CO (United States)
- Publication Date:
- Research Org.:
- Colorado State Univ., Fort Collins, CO (United States)
- Sponsoring Org.:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE); National Science Foundation (NSF)
- OSTI Identifier:
- 1670786
- Grant/Contract Number:
- EE0008557
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Thin Solid Films
- Additional Journal Information:
- Journal Volume: 691; Journal ID: ISSN 0040-6090
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 14 SOLAR ENERGY; Magnesium-doped zinc oxide; Thin film solar cells; Cadmium telluride; Buffer; Degradation; Hydroxide; Surface contamination
Citation Formats
Bittau, Francesco, Jagdale, Shridhar, Potamialis, Christos, Bowers, Jake W., Walls, John M., Munshi, Amit H., Barth, Kurt L., and Sampath, Walajabad S. Degradation of Mg-doped zinc oxide buffer layers in thin film CdTe solar cells. United States: N. p., 2019.
Web. doi:10.1016/j.tsf.2019.137556.
Bittau, Francesco, Jagdale, Shridhar, Potamialis, Christos, Bowers, Jake W., Walls, John M., Munshi, Amit H., Barth, Kurt L., & Sampath, Walajabad S. Degradation of Mg-doped zinc oxide buffer layers in thin film CdTe solar cells. United States. https://doi.org/10.1016/j.tsf.2019.137556
Bittau, Francesco, Jagdale, Shridhar, Potamialis, Christos, Bowers, Jake W., Walls, John M., Munshi, Amit H., Barth, Kurt L., and Sampath, Walajabad S. Mon .
"Degradation of Mg-doped zinc oxide buffer layers in thin film CdTe solar cells". United States. https://doi.org/10.1016/j.tsf.2019.137556. https://www.osti.gov/servlets/purl/1670786.
@article{osti_1670786,
title = {Degradation of Mg-doped zinc oxide buffer layers in thin film CdTe solar cells},
author = {Bittau, Francesco and Jagdale, Shridhar and Potamialis, Christos and Bowers, Jake W. and Walls, John M. and Munshi, Amit H. and Barth, Kurt L. and Sampath, Walajabad S.},
abstractNote = {Cadmium Sulphide is the conventional n-type buffer layer used in thin film Cadmium Telluride solar cells. It is well known that Cadmium Sulphide causes optical losses and sulphur diffuses into the absorber during high temperature activation. Sputter-deposited Mg-doped ZnO (MZO) has been shown to be an attractive buffer layer for Cadmium Telluride solar cells due to its transparency and tuneable band gap. It is also stable to high temperature processing and avoids diffusion of elements into the cadmium telluride absorber during the cadmium chloride activation treatment. However, degradation is observed in solar cells incorporating MZO buffer layers. Analysis of the MZO film surface potential has revealed significant fluctuations in the thin film work function once the layer is exposed to the atmosphere following deposition. These fluctuations are attributed to the high reactivity to water vapour of the MgO contained in the MZO films. This has been analysed using X-ray Photoelectron Spectroscopy to determine corresponding changes in the surface chemistry. The Zinc Oxide component is relatively stable, but the analysis shows that MgO forms a Mg(OH)2 layer on the MZO surface which forms a secondary barrier at the MZO/CdTe interface and/or at the interface between MZO and the Fluorine-doped SnO2. This affects the Fill Factor and as a consequence it degrades the conversion efficiency.},
doi = {10.1016/j.tsf.2019.137556},
journal = {Thin Solid Films},
number = ,
volume = 691,
place = {United States},
year = {Mon Sep 09 00:00:00 EDT 2019},
month = {Mon Sep 09 00:00:00 EDT 2019}
}
Figures / Tables:
Works referenced in this record:
High-efficiency polycrystalline CdTe thin-film solar cells
journal, December 2004
- Wu, Xuanzhi
- Solar Energy, Vol. 77, Issue 6
Evolution of oxygenated cadmium sulfide (CdS:O) during high-temperature CdTe solar cell fabrication
journal, December 2016
- Meysing, Daniel M.; Reese, Matthew O.; Warren, Charles W.
- Solar Energy Materials and Solar Cells, Vol. 157
Structural and chemical evolution of the CdS:O window layer during individual CdTe solar cell processing steps
journal, January 2018
- Abbas, A.; Meysing, D. M.; Reese, M. O.
- Solar Energy, Vol. 159
Cadmium Chloride Assisted Re-Crystallisation of CdTe: The Effect on the CdS Window Layer
journal, January 2015
- Abbas, Ali; Kaminski, Piotr; West, Geoff
- MRS Proceedings, Vol. 1738
Emitter/absorber interface of CdTe solar cells
journal, June 2016
- Song, Tao; Kanevce, Ana; Sites, James R.
- Journal of Applied Physics, Vol. 119, Issue 23
Analysis and optimisation of the glass/TCO/MZO stack for thin film CdTe solar cells
journal, December 2018
- Bittau, Francesco; Potamialis, Christos; Togay, Mustafa
- Solar Energy Materials and Solar Cells, Vol. 187
Band alignment of front contact layers for high-efficiency CdTe solar cells
journal, December 2016
- Kephart, J. M.; McCamy, J. W.; Ma, Z.
- Solar Energy Materials and Solar Cells, Vol. 157
Annealing effects on Zn1−xMgxO/CIGS interfaces characterized by ultraviolet light excited time-resolved photoluminescence
journal, September 2008
- Shimakawa, Shin-ichi; Hashimoto, Yasuhiro; Hayashi, Shigeo
- Solar Energy Materials and Solar Cells, Vol. 92, Issue 9
Influence of sputtering a ZnMgO window layer on the interface and bulk properties of Cu(In,Ga)Se[sub 2] solar cells
journal, January 2009
- Li, Jian V.; Li, Xiaonan; Yan, Yanfa
- Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, Vol. 27, Issue 6
Polycrystalline CdSeTe/CdTe Absorber Cells With 28 mA/cm 2 Short-Circuit Current
journal, January 2018
- Munshi, Amit H.; Kephart, Jason; Abbas, Ali
- IEEE Journal of Photovoltaics, Vol. 8, Issue 1
Work function changes upon water contamination of metal surfaces
journal, March 1980
- Heras, J. M.; Viscido, L.
- Applications of Surface Science, Vol. 4, Issue 2
Dependence of indium–tin–oxide work function on surface cleaning method as studied by ultraviolet and x-ray photoemission spectroscopies
journal, January 2000
- Sugiyama, Kiyoshi; Ishii, Hisao; Ouchi, Yukio
- Journal of Applied Physics, Vol. 87, Issue 1
Influences of thermal annealing and humidity exposure on surface structure of (100) single-crystal MgO substrate
journal, May 1999
- Delplancke-Ogletree, M. P.; Ye, M.; Winand, R.
- Journal of Materials Research, Vol. 14, Issue 5
Morphology, surface topography and optical studies on electron beam evaporated MgO thin films
journal, October 2006
- Chowdhury, A.; Kumar, J.
- Bulletin of Materials Science, Vol. 29, Issue 5
A first quantitative XPS study of the surface films formed, by exposure to water, on Mg and on the Mg–Al intermetallics: Al3Mg2 and Mg17Al12
journal, May 2009
- Liu, Ming; Zanna, Sandrine; Ardelean, Helene
- Corrosion Science, Vol. 51, Issue 5
An XPS investigation of the oxidation/corrosion of melt-spun Mg
journal, May 2000
- Yao, H. B.; Li, Y.; Wee, A. T. S.
- Applied Surface Science, Vol. 158, Issue 1-2
Transparent Conducting Oxides for Photovoltaics: Manipulation of Fermi Level, Work Function and Energy Band Alignment
journal, November 2010
- Klein, Andreas; Körber, Christoph; Wachau, André
- Materials, Vol. 3, Issue 11
Interface-Barrier-Induced J–V Distortion of CIGS Cells With Sputtered-Deposited Zn(S,O) Window Layers
journal, May 2014
- Song, Tao; Tyler McGoffin, J.; Sites, James R.
- IEEE Journal of Photovoltaics, Vol. 4, Issue 3
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