Intermixing and Formation of Cu-Rich Secondary Phases at Sputtered CdS/CuInGaSe2 Heterojunctions

He, Xiaoqing; Varley, Joel; Ercius, Peter; Erikson, Thomson; Bailey, Jeff; Zapalac, Geordie; Poplavskyy, Dmitry; Mackie, Neil; Bayman, Atiye; Lordi, Vincenzo; Rockett, Angus

doi:10.1109/JPHOTOV.2016.2589362

Title: Intermixing and Formation of Cu-Rich Secondary Phases at Sputtered CdS/CuInGaSe₂ Heterojunctions

Abstract

In this work, the Cu migration behavior in PVD-CdS/PVD-Cu(In,Ga)Se₂ (CIGS) heterojunctions is investigated by high-resolution electron microscopy (HREM) and energy dispersive X-ray spectroscopy (EDS). Incorporation of Cu into the CdS forms Cu-rich domains but has no effect on epitaxy of the CdS. Epitaxy is commonly observed in the CdS studied. Secondary ion mass spectroscopy depth profiles confirm the presence of Cu in the CdS. In some cases, Cd is completely replaced by Cu, resulting in a Cu-S binary compound epitaxially grown on the CIGS and fully coherent with the surrounding CdS. This is most likely to be cubic Cu₂S, based on lattice spacing measurements from HREM images and EDS elemental quantification. In addition, we find that the buffer layer crystal structure influences the extent of Ga depletion at the CIGS surface, which is more pronounced adjacent to zinc-blende CdS than wurtzite CdS. Density functional theory calculations reveal that Cu clustering and different Ga depletion widths can be attributed to the inherent anisotropy of wurtzite CdS and differences in CIGS point-defect migration barriers. Understanding the influence of these effects on device properties is a critical step in developing more efficient CdS/CIGS-based photovoltaics.

Authors:

He, Xiaoqing ^[1]; Varley, Joel ^[2]; Ercius, Peter ^[3]; Erikson, Thomson ^[1]; Bailey, Jeff ^[4]; Zapalac, Geordie ^[4]; Poplavskyy, Dmitry ^[4]; Mackie, Neil ^[4]; Bayman, Atiye ^[4]; Lordi, Vincenzo ^[2]; Rockett, Angus ^[1]

Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Materials Science and Engineering
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Center for Electron Microscopy
MiaSole Hi-Tech Corp., Santa Clara, CA (United States)

Publication Date:: Mon Aug 08 00:00:00 EDT 2016

Research Org.:: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:: SC-22.3 USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division; USDOE Office of Energy Efficiency and Renewable Energy (EERE); Univ. of Illinois at Urbana-Champaign, IL (United States); National Science Foundation (NSF)

OSTI Identifier:: 1440938

Grant/Contract Number:: AC02-05CH11231; CPS25853; EE0005956; AC52-07NA27344; DMR-0959470

Resource Type:: Accepted Manuscript

Journal Name:: IEEE Journal of Photovoltaics

Additional Journal Information:: Journal Volume: 6; Journal Issue: 5; Related Information: © 2011-2012 IEEE.; Journal ID: ISSN 2156-3381

Publisher:: IEEE

Country of Publication:: United States

Language:: English

Subject:: 14 SOLAR ENERGY; 36 MATERIALS SCIENCE; CdS structure; Cu(In,Ga)Se2 (CIGS) photovoltaics; secondary ion mass spectrometry (SIMS) depth profile; STEM-EDS mapping; transmission electron microscopy; heterojunctions; ions; microscopy; epitaxial growth; surface treatment; lattices; photovoltaic systems

Citation Formats


                    He, Xiaoqing, Varley, Joel, Ercius, Peter, Erikson, Thomson, Bailey, Jeff, Zapalac, Geordie, Poplavskyy, Dmitry, Mackie, Neil, Bayman, Atiye, Lordi, Vincenzo, and Rockett, Angus. Intermixing and Formation of Cu-Rich Secondary Phases at Sputtered CdS/CuInGaSe2 Heterojunctions.  United States: N. p., 2016. 
Web.  doi:10.1109/JPHOTOV.2016.2589362.

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                    He, Xiaoqing, Varley, Joel, Ercius, Peter, Erikson, Thomson, Bailey, Jeff, Zapalac, Geordie, Poplavskyy, Dmitry, Mackie, Neil, Bayman, Atiye, Lordi, Vincenzo, & Rockett, Angus. Intermixing and Formation of Cu-Rich Secondary Phases at Sputtered CdS/CuInGaSe2 Heterojunctions.  United States.  https://doi.org/10.1109/JPHOTOV.2016.2589362

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                    He, Xiaoqing, Varley, Joel, Ercius, Peter, Erikson, Thomson, Bailey, Jeff, Zapalac, Geordie, Poplavskyy, Dmitry, Mackie, Neil, Bayman, Atiye, Lordi, Vincenzo, and Rockett, Angus. Mon .  
"Intermixing and Formation of Cu-Rich Secondary Phases at Sputtered CdS/CuInGaSe2 Heterojunctions".  United States.  https://doi.org/10.1109/JPHOTOV.2016.2589362.  https://www.osti.gov/servlets/purl/1440938.

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@article{osti_1440938,

  title        = {Intermixing and Formation of Cu-Rich Secondary Phases at Sputtered CdS/CuInGaSe2 Heterojunctions},

  author       = {He, Xiaoqing and Varley, Joel and Ercius, Peter and Erikson, Thomson and Bailey, Jeff and Zapalac, Geordie and Poplavskyy, Dmitry and Mackie, Neil and Bayman, Atiye and Lordi, Vincenzo and Rockett, Angus},

  abstractNote = {In this work, the Cu migration behavior in PVD-CdS/PVD-Cu(In,Ga)Se2 (CIGS) heterojunctions is investigated by high-resolution electron microscopy (HREM) and energy dispersive X-ray spectroscopy (EDS). Incorporation of Cu into the CdS forms Cu-rich domains but has no effect on epitaxy of the CdS. Epitaxy is commonly observed in the CdS studied. Secondary ion mass spectroscopy depth profiles confirm the presence of Cu in the CdS. In some cases, Cd is completely replaced by Cu, resulting in a Cu-S binary compound epitaxially grown on the CIGS and fully coherent with the surrounding CdS. This is most likely to be cubic Cu2S, based on lattice spacing measurements from HREM images and EDS elemental quantification. In addition, we find that the buffer layer crystal structure influences the extent of Ga depletion at the CIGS surface, which is more pronounced adjacent to zinc-blende CdS than wurtzite CdS. Density functional theory calculations reveal that Cu clustering and different Ga depletion widths can be attributed to the inherent anisotropy of wurtzite CdS and differences in CIGS point-defect migration barriers. Understanding the influence of these effects on device properties is a critical step in developing more efficient CdS/CIGS-based photovoltaics.},

  doi          = {10.1109/JPHOTOV.2016.2589362},

  journal      = {IEEE Journal of Photovoltaics},

  number       = 5,

  volume       = 6,

  place        = {United States},

  year         = {Mon Aug 08 00:00:00 EDT 2016},

  month        = {Mon Aug 08 00:00:00 EDT 2016}

}

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Works referencing / citing this record:

The role of oxygen doping on elemental intermixing at the PVD-CdS/Cu (InGa)Se ₂ heterojunction
journal, December 2018

He, Xiaoqing; Ercius, Peter; Varley, Joel
Progress in Photovoltaics: Research and Applications, Vol. 27, Issue 3
DOI: 10.1002/pip.3087

Assessing the role of hydrogen in Fermi-level pinning in chalcopyrite and kesterite solar absorbers from first-principles calculations
journal, April 2018

Varley, J. B.; Lordi, V.; Ogitsu, T.
Journal of Applied Physics, Vol. 123, Issue 16
DOI: 10.1063/1.5006272

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Similar Records

Title: Intermixing and Formation of Cu-Rich Secondary Phases at Sputtered CdS/CuInGaSe2 Heterojunctions

Abstract

Citation Formats

The role of oxygen doping on elemental intermixing at the PVD-CdS/Cu (InGa)Se 2 heterojunction journal, December 2018

Assessing the role of hydrogen in Fermi-level pinning in chalcopyrite and kesterite solar absorbers from first-principles calculations journal, April 2018

Title: Intermixing and Formation of Cu-Rich Secondary Phases at Sputtered CdS/CuInGaSe₂ Heterojunctions

The role of oxygen doping on elemental intermixing at the PVD-CdS/Cu (InGa)Se ₂ heterojunction
journal, December 2018

Assessing the role of hydrogen in Fermi-level pinning in chalcopyrite and kesterite solar absorbers from first-principles calculations
journal, April 2018