Get access

Confined and Chemically Flexible Grain Boundaries in Polycrystalline Compound Semiconductors

Authors

  • Daniel Abou-Ras,

    Corresponding author
    1. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
    • Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
    Search for more papers by this author
  • Sebastian S. Schmidt,

    1. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
    Search for more papers by this author
  • Raquel Caballero,

    1. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
    Current affiliation:
    1. Universidad Autónoma de Madrid, Departamento de Física Aplicada, C/Francisco Tomás y Valiente 7, 28049 Madrid, Spain
    Search for more papers by this author
  • Thomas Unold,

    1. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
    Search for more papers by this author
  • Hans-Werner Schock,

    1. Department of Engineering, George Holt Building, Ashton Street, Liverpool, L69 3BX, UK
    Search for more papers by this author
  • Christoph T. Koch,

    1. Max-Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
    Current affiliation:
    1. Institute for Experimental Physics, Ulm University, 89069 Ulm, Germany
    Search for more papers by this author
  • Bernhard Schaffer,

    1. SuperSTEM, STFC Daresbury Laboratories, Keckwick Lane, Warrington, WA4 4AD, UK
    2. SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
    Search for more papers by this author
  • Miroslava Schaffer,

    1. SuperSTEM, STFC Daresbury Laboratories, Keckwick Lane, Warrington, WA4 4AD, UK
    2. Department of Engineering, George Holt Building, Ashton Street, Liverpool, L69 3BX, UK
    Search for more papers by this author
  • Pyuck-Pa Choi,

    1. Max-Planck-Institut für Eisenforschung GmbH, Department of Microstructure Physics and Alloy Design, Max-Planck-Strasse 1, 40237 Düsseldorf, Germany
    Search for more papers by this author
  • Oana Cojocaru-Mirédin

    1. Max-Planck-Institut für Eisenforschung GmbH, Department of Microstructure Physics and Alloy Design, Max-Planck-Strasse 1, 40237 Düsseldorf, Germany
    Search for more papers by this author

Abstract

Grain boundaries (GBs) in polycrystalline Cu(In,Ga)Se2 thin films exhibit only slightly enhanced recombination, as compared with the grain interiors, allowing for very high power-conversion efficiencies of more than 20% in the corresponding solar-cell devices. This work highlights the specific compositional and electrical properties of Cu(In,Ga)Se2 GBs by application of appropriate subnanometer characterisation techniques: inline electron holography, electron energy-loss spectroscopy, and atom-probe tomography. It is found that changes of composition at the GBs are confined to regions of only about 1 nm in width. Therefore, these compositional changes are not due to secondary phases but atomic or ionic redistribution within the atomic planes close to the GBs. For different GBs in the Cu(In,Ga)Se2 thin film investigated, different atomic or ionic redistributions are also found. This chemical flexibility makes polycrystalline Cu(In,Ga)Se2 thin films particularly suitable for photovoltaic applications.

Ancillary