Cd doping at PVD-CdS/CuInGaSe2 heterojunctions

He, Xiaoqing; Paulauskas, Tadas; Ercius, Peter; Varley, Joel; Bailey, Jeff; Zapalac, Geordie; Poplavskyy, Dmitry; Mackie, Neil; Bayman, Atiye; Spaulding, David; Klie, Robert; Lordi, Vincenzo; Rockett, Angus

doi:10.1016/j.solmat.2017.01.043

Cd doping at PVD-CdS/CuInGaSe₂ heterojunctions

Journal Article · Mon Feb 20 00:00:00 EST 2017 · Solar Energy Materials and Solar Cells

DOI:https://doi.org/10.1016/j.solmat.2017.01.043· OSTI ID:1366899

He, Xiaoqing ^[1]; Paulauskas, Tadas ^[2]; Ercius, Peter ^[3]; Varley, Joel ^[4]; Bailey, Jeff ^[5]; Zapalac, Geordie ^[5]; Poplavskyy, Dmitry ^[5]; Mackie, Neil ^[5]; Bayman, Atiye ^[5]; Spaulding, David ^[5]; Klie, Robert ^[2]; Lordi, Vincenzo ^[4]; Rockett, Angus ^[1]

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

In this paper, we report on direct evidence of Cd doping of the CuInGaSe₂ (CIGS) surface in physical vapor deposited (PVD) CdS/CIGS heterojunctions by scanning transmission electron microscopy (STEM) and related techniques. We find Cd doping of the CIGS near-surface region regardless of the presence or absence of Cu rich domains in the CdS for both zinc-blende (zb) and wurtzite (wz) CdS. However, we find that the Cd penetrates much farther into the CIGS when Cu-rich domains are present in the CdS. This suggests that Cu exchanges with Cd, increasing the concentration gradient for Cd in the CIGS and thus driving Cd into the CIGS surface. The Cd doping is clearly resolved at atomic resolution in aberration-corrected STEM-high angle annular dark field images. In zb-CdS/CIGS heterojunctions, Cd is shown to substitute for both Cu and Ga atoms, while in wz-CdS/CIGS heterojunctions Cd seems to predominantly occupy Cu sites. Finally, Cd doping in the CIGS surface layer suggests the formation of a p-n homojunction in the CIGS, which may account for the high device efficiencies, comparable to CBD-CdS/CIGS processed structures.

View Accepted Manuscript (DOE)

Research Organization:: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of Illinois, Urbana, IL (United States)

Sponsoring Organization:: National Science Foundation (NSF) (United States); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)

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

OSTI ID:: 1366899

Alternate ID(s):: OSTI ID: 1435084
OSTI ID: 1398611

Report Number(s):: LLNL-JRNL--708969

Journal Information:: Solar Energy Materials and Solar Cells, Journal Name: Solar Energy Materials and Solar Cells Vol. 164; ISSN 0927-0248

Publisher:: ElsevierCopyright Statement

Country of Publication:: United States

Language:: English

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The role of oxygen doping on elemental intermixing at the PVD-CdS/Cu (InGa)Se ₂ heterojunction He, Xiaoqing; Ercius, Peter; Varley, Joel Progress in Photovoltaics: Research and Applications, Vol. 27, Issue 3 https://doi.org/10.1002/pip.3087	journal	December 2018
A short review on the advancements in electroplating of CuInGaSe2 thin films Chandran, Ramkumar; Panda, Subhendu K.; Mallik, Archana Materials for Renewable and Sustainable Energy, Vol. 7, Issue 2 https://doi.org/10.1007/s40243-018-0112-1	journal	March 2018
Assessing the role of hydrogen in Fermi-level pinning in chalcopyrite and kesterite solar absorbers from first-principles calculations Varley, J. B.; Lordi, V.; Ogitsu, T. Journal of Applied Physics, Vol. 123, Issue 16 https://doi.org/10.1063/1.5006272	journal	April 2018
Thin‐film solar cells exceeding 22% solar cell efficiency: An overview on CdTe-, Cu(In,Ga)Se ₂ -, and perovskite-based materials Powalla, Michael; Paetel, Stefan; Ahlswede, Erik Applied Physics Reviews, Vol. 5, Issue 4 https://doi.org/10.1063/1.5061809	journal	December 2018
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Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Cd doping
Cu(In
Ga)Se2 photovoltaics
STEM-EDS mapping
atomic resolution
p-n homojunction
physical vapor deposition