skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Rubidium Fluoride Post-Deposition Treatment: Impact on the Chemical Structure of the Cu(In,Ga)Se2 Surface and CdS/Cu(In,Ga)Se2 Interface in Thin-Film Solar Cells

Abstract

Here, we present a detailed characterization of the chemical structure of the Cu(In,Ga)Se2 thin-film surface and the CdS/Cu(In,Ga)Se2 interface, both with and without a RbF post-deposition treatment (RbF-PDT). For this purpose, X-ray photoelectron and Auger electron spectroscopy, as well as synchrotron-based soft X-ray emission spectroscopy have been employed. Although some similarities with the reported impacts of light-element alkali PDT (i.e., NaF- and KF-PDT) are found, we observe some distinct differences, which might be the reason for the further improved conversion efficiency with heavy-element alkali PDT. In particular, we find that the RbF-PDT reduces, but not fully removes, the copper content at the absorber surface and does not induce a significant change in the Ga/(Ga + In) ratio. Additionally, we observe an increased amount of indium and gallium oxides at the surface of the treated absorber. These oxides are partly (in the case of indium) and completely (in the case of gallium) removed from the CdS/Cu(In,Ga)Se2 interface by the chemical bath deposition of the CdS buffer.

Authors:
 [1]; ORCiD logo [2];  [3];  [3];  [3];  [4]; ORCiD logo [5];  [6];  [3];  [7];  [7]
  1. Karlsruhe Inst. of Technology (KIT), Hermann-v.-Helmholtz-Platz (Germany)
  2. Karlsruhe Inst. of Technology (KIT), Hermann-v.-Helmholtz-Platz (Germany); Univ. of Würzburg (Germany)
  3. Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), Stuttgart (Germany)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Univ. of Nevada, Las Vegas, NV (United States)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
  6. Univ. of Würzburg (Germany)
  7. Karlsruhe Inst. of Technology (KIT), Hermann-v.-Helmholtz-Platz (Germany); Univ. of Nevada, Las Vegas, NV (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1594899
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 10; Journal Issue: 43; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Cu(In,Ga)Se2; thin films; CIGSe solar cell; RbF post-deposition treatment; soft X-ray spectroscopy; high efficiency; chemical structure

Citation Formats

Kreikemeyer-Lorenzo, Dagmar, Hauschild, Dirk, Jackson, Philip, Friedlmeier, Theresa M., Hariskos, Dimitrios, Blum, Monika, Yang, Wanli, Reinert, Friedrich, Powalla, Michael, Heske, Clemens, and Weinhardt, Lothar. Rubidium Fluoride Post-Deposition Treatment: Impact on the Chemical Structure of the Cu(In,Ga)Se2 Surface and CdS/Cu(In,Ga)Se2 Interface in Thin-Film Solar Cells. United States: N. p., 2018. Web. https://doi.org/10.1021/acsami.8b10005.
Kreikemeyer-Lorenzo, Dagmar, Hauschild, Dirk, Jackson, Philip, Friedlmeier, Theresa M., Hariskos, Dimitrios, Blum, Monika, Yang, Wanli, Reinert, Friedrich, Powalla, Michael, Heske, Clemens, & Weinhardt, Lothar. Rubidium Fluoride Post-Deposition Treatment: Impact on the Chemical Structure of the Cu(In,Ga)Se2 Surface and CdS/Cu(In,Ga)Se2 Interface in Thin-Film Solar Cells. United States. https://doi.org/10.1021/acsami.8b10005
Kreikemeyer-Lorenzo, Dagmar, Hauschild, Dirk, Jackson, Philip, Friedlmeier, Theresa M., Hariskos, Dimitrios, Blum, Monika, Yang, Wanli, Reinert, Friedrich, Powalla, Michael, Heske, Clemens, and Weinhardt, Lothar. Mon . "Rubidium Fluoride Post-Deposition Treatment: Impact on the Chemical Structure of the Cu(In,Ga)Se2 Surface and CdS/Cu(In,Ga)Se2 Interface in Thin-Film Solar Cells". United States. https://doi.org/10.1021/acsami.8b10005. https://www.osti.gov/servlets/purl/1594899.
@article{osti_1594899,
title = {Rubidium Fluoride Post-Deposition Treatment: Impact on the Chemical Structure of the Cu(In,Ga)Se2 Surface and CdS/Cu(In,Ga)Se2 Interface in Thin-Film Solar Cells},
author = {Kreikemeyer-Lorenzo, Dagmar and Hauschild, Dirk and Jackson, Philip and Friedlmeier, Theresa M. and Hariskos, Dimitrios and Blum, Monika and Yang, Wanli and Reinert, Friedrich and Powalla, Michael and Heske, Clemens and Weinhardt, Lothar},
abstractNote = {Here, we present a detailed characterization of the chemical structure of the Cu(In,Ga)Se2 thin-film surface and the CdS/Cu(In,Ga)Se2 interface, both with and without a RbF post-deposition treatment (RbF-PDT). For this purpose, X-ray photoelectron and Auger electron spectroscopy, as well as synchrotron-based soft X-ray emission spectroscopy have been employed. Although some similarities with the reported impacts of light-element alkali PDT (i.e., NaF- and KF-PDT) are found, we observe some distinct differences, which might be the reason for the further improved conversion efficiency with heavy-element alkali PDT. In particular, we find that the RbF-PDT reduces, but not fully removes, the copper content at the absorber surface and does not induce a significant change in the Ga/(Ga + In) ratio. Additionally, we observe an increased amount of indium and gallium oxides at the surface of the treated absorber. These oxides are partly (in the case of indium) and completely (in the case of gallium) removed from the CdS/Cu(In,Ga)Se2 interface by the chemical bath deposition of the CdS buffer.},
doi = {10.1021/acsami.8b10005},
journal = {ACS Applied Materials and Interfaces},
number = 43,
volume = 10,
place = {United States},
year = {2018},
month = {10}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 5 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Sodium incorporation strategies for CIGS growth at different temperatures
journal, June 2005


The influence of Na on metastable defect kinetics in CIGS materials
journal, February 2009


The influence of Na on low temperature growth of CIGS thin film solar cells on polyimide substrates
journal, February 2009


Influence of Na on Cu(In,Ga)Se2 solar cells grown on polyimide substrates at low temperature: Impact on the Cu(In,Ga)Se2/Mo interface
journal, March 2010

  • Caballero, R.; Kaufmann, C. A.; Eisenbarth, T.
  • Applied Physics Letters, Vol. 96, Issue 9
  • DOI: 10.1063/1.3340459

Alternative sodium sources for Cu(In,Ga)Se2 thin-film solar cells on flexible substrates
journal, August 2011


Effect of sodium incorporation into CuInSe 2 from first principles
journal, August 2013

  • Oikkonen, L. E.; Ganchenkova, M. G.; Seitsonen, A. P.
  • Journal of Applied Physics, Vol. 114, Issue 8
  • DOI: 10.1063/1.4819105

Effect of sodium on material and device quality in low temperature deposited Cu(In,Ga)Se2
journal, December 2013


Potassium-induced surface modification of Cu(In,Ga)Se2 thin films for high-efficiency solar cells
journal, November 2013

  • Chirilă, Adrian; Reinhard, Patrick; Pianezzi, Fabian
  • Nature Materials, Vol. 12, Issue 12
  • DOI: 10.1038/nmat3789

Unveiling the effects of post-deposition treatment with different alkaline elements on the electronic properties of CIGS thin film solar cells
journal, January 2014

  • Pianezzi, Fabian; Reinhard, Patrick; Chirilă, Adrian
  • Physical Chemistry Chemical Physics, Vol. 16, Issue 19
  • DOI: 10.1039/c4cp00614c

Experimental indication for band gap widening of chalcopyrite solar cell absorbers after potassium fluoride treatment
journal, August 2014

  • Pistor, P.; Greiner, D.; Kaufmann, C. A.
  • Applied Physics Letters, Vol. 105, Issue 6
  • DOI: 10.1063/1.4892882

Investigation of the effect of potassium on Cu(In,Ga)Se 2 layers and solar cells
journal, May 2015


Revealing Surface Modifications of Potassium-Fluoride-Treated Cu(In,Ga)Se 2 : A Study of Material Structure, Chemistry, and Photovoltaic Performance
journal, July 2016

  • Aguiar, Jeffery A.; Stokes, Adam; Jiang, Chun-Sheng
  • Advanced Materials Interfaces, Vol. 3, Issue 17
  • DOI: 10.1002/admi.201600013

Beneficial effect of post-deposition treatment in high-efficiency Cu(In,Ga)Se2 solar cells through reduced potential fluctuations
journal, August 2016

  • Jensen, S. A.; Glynn, S.; Kanevce, A.
  • Journal of Applied Physics, Vol. 120, Issue 6
  • DOI: 10.1063/1.4960344

Formation of a K—In—Se Surface Species by NaF/KF Postdeposition Treatment of Cu(In,Ga)Se 2 Thin-Film Solar Cell Absorbers
journal, January 2017

  • Handick, Evelyn; Reinhard, Patrick; Wilks, Regan G.
  • ACS Applied Materials & Interfaces, Vol. 9, Issue 4
  • DOI: 10.1021/acsami.6b11892

KF post-deposition treatment of industrial Cu(In, Ga)(S, Se) 2 thin-film surfaces: Modifying the chemical and electronic structure
journal, August 2017

  • Mezher, Michelle; Mansfield, Lorelle M.; Horsley, Kimberly
  • Applied Physics Letters, Vol. 111, Issue 7
  • DOI: 10.1063/1.4998445

Impact of a RbF Postdeposition Treatment on the Electronic Structure of the CdS/Cu(In,Ga)Se 2 Heterojunction in High-Efficiency Thin-Film Solar Cells
journal, September 2017


Compositional investigation of potassium doped Cu(In,Ga)Se 2 solar cells with efficiencies up to 20.8% : Compositional investigation of potassium doped Cu(In,Ga)Se
journal, February 2014

  • Jackson, Philip; Hariskos, Dimitrios; Wuerz, Roland
  • physica status solidi (RRL) - Rapid Research Letters, Vol. 8, Issue 3
  • DOI: 10.1002/pssr.201409040

Properties of Cu(In,Ga)Se 2 solar cells with new record efficiencies up to 21.7% : Properties of Cu(In,Ga)Se
journal, December 2014

  • Jackson, Philip; Hariskos, Dimitrios; Wuerz, Roland
  • physica status solidi (RRL) - Rapid Research Letters, Vol. 9, Issue 1
  • DOI: 10.1002/pssr.201409520

Cover Picture: Effects of heavy alkali elements in Cu(In,Ga)Se 2 solar cells with efficiencies up to 22.6% (Phys. Status Solidi RRL 8/2016)
journal, August 2016

  • Jackson, Philip; Wuerz, Roland; Hariskos, Dimitrios
  • physica status solidi (RRL) - Rapid Research Letters, Vol. 10, Issue 8
  • DOI: 10.1002/pssr.201670747

Evidence for Chemical and Electronic Nonuniformities in the Formation of the Interface of RbF-Treated Cu(In,Ga)Se 2 with CdS
journal, December 2017

  • Nicoara, Nicoleta; Kunze, Thomas; Jackson, Philip
  • ACS Applied Materials & Interfaces, Vol. 9, Issue 50
  • DOI: 10.1021/acsami.7b12448

First experimental results from IBM/TENN/TULANE/LLNL/LBL undulator beamline at the advanced light source
journal, February 1995

  • Jia, J. J.; Callcott, T. A.; Yurkas, J.
  • Review of Scientific Instruments, Vol. 66, Issue 2
  • DOI: 10.1063/1.1145985

Na‐induced effects on the electronic structure and composition of Cu(In,Ga)Se 2 thin‐film surfaces
journal, June 1996

  • Heske, C.; Fink, R.; Umbach, E.
  • Applied Physics Letters, Vol. 68, Issue 24
  • DOI: 10.1063/1.115783

Atomic subshell photoionization cross sections and asymmetry parameters: 1 ⩽ Z ⩽ 103
journal, January 1985


Calculations of electron inelastic mean free paths. V. Data for 14 organic compounds over the 50-2000 eV range
journal, March 1994

  • Tanuma, S.; Powell, C. J.; Penn, D. R.
  • Surface and Interface Analysis, Vol. 21, Issue 3
  • DOI: 10.1002/sia.740210302

Influence of Na and H2O on the surface properties of Cu(In,Ga)Se2 thin films
journal, September 1997

  • Heske, C.; Richter, G.; Chen, Zhonghui
  • Journal of Applied Physics, Vol. 82, Issue 5
  • DOI: 10.1063/1.366096

Na impurity chemistry in photovoltaic CIGS thin films: Investigation with x-ray photoelectron spectroscopy
journal, November 1997

  • Niles, David W.; Ramanathan, Kannan; Hasoon, Falah
  • Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, Vol. 15, Issue 6
  • DOI: 10.1116/1.580902

Influence of substrates on the electrical properties of Cu(In,Ga)Se2 thin films
journal, June 1996


Impact of environmental conditions on the chemical surface properties of Cu(In,Ga)(S,Se) 2 thin-film solar cell absorbers
journal, May 2014

  • Hauschild, D.; Meyer, F.; Pohlner, S.
  • Journal of Applied Physics, Vol. 115, Issue 18
  • DOI: 10.1063/1.4876257

Characterization of Sulfur Bonding in CdS:O Buffer Layers for CdTe-based Thin-Film Solar Cells
journal, July 2015

  • Duncan, Douglas A.; Kephart, Jason M.; Horsley, Kimberly
  • ACS Applied Materials & Interfaces, Vol. 7, Issue 30
  • DOI: 10.1021/acsami.5b03503

Chemical shifts of Auger lines, and the Auger parameter
journal, January 1975


Fityk : a general-purpose peak fitting program
journal, September 2010


Improving performance by Na doping of a buffer layer-chemical and electronic structure of the In x S y :Na/CuIn(S,Se) 2 thin-film solar cell interface
journal, February 2018

  • Hauschild, Dirk; Meyer, Frank; Benkert, Andreas
  • Progress in Photovoltaics: Research and Applications, Vol. 26, Issue 5
  • DOI: 10.1002/pip.2993

XPS investigation of anodic oxides grown on p-type InP
journal, November 1990

  • Faur, Maria; Faur, Mircea; Jayne, D. T.
  • Surface and Interface Analysis, Vol. 15, Issue 11
  • DOI: 10.1002/sia.740151102

Resonant inelastic soft x-ray scattering of CdS: A two-dimensional electronic structure map approach
journal, April 2009


Inducing and monitoring photoelectrochemical reactions at surfaces and buried interfaces in Cu(In,Ga)(S,Se)2 thin-film solar cells
journal, April 2005

  • Reichardt, J.; Bär, M.; Grimm, A.
  • Applied Physics Letters, Vol. 86, Issue 17
  • DOI: 10.1063/1.1906309

Monitoring chemical reactions at a liquid–solid interface: Water on CuIn(S,Se)2 thin film solar cell absorbers
journal, November 2003

  • Heske, C.; Groh, U.; Fuchs, O.
  • The Journal of Chemical Physics, Vol. 119, Issue 20
  • DOI: 10.1063/1.1627328

    Works referencing / citing this record:

    Heavy Alkali Treatment of Cu(In,Ga)Se 2 Solar Cells: Surface versus Bulk Effects
    journal, January 2020

    • Siebentritt, Susanne; Avancini, Enrico; Bär, Marcus
    • Advanced Energy Materials, Vol. 10, Issue 8
    • DOI: 10.1002/aenm.201903752

    Surface and Interface Properties in Thin‐Film Solar Cells: Using Soft X‐rays and Electrons to Unravel the Electronic and Chemical Structure
    journal, February 2019

    • Weinhardt, Lothar; Hauschild, Dirk; Heske, Clemens
    • Advanced Materials, Vol. 31, Issue 26
    • DOI: 10.1002/adma.201806660