Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 5: Photovoltaics: CIGS and related compounds

HL 5.5: Vortrag

Montag, 16. März 2015, 10:30–10:45, EW 202

Composition-dependent atomic-scale structure of the Cu-(In,Ga)-Se system — •Erik Haubold¹, Philipp Schöppe¹, Stefanie Eckner¹, Susan Schorr², Francesco di Benedetto³, Ivan Colantoni⁴, Francesco d’Acapito⁴, and Claudia S. Schnohr¹ — ¹Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany — ²Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin & Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74-100, 12249 Berlin, Germany — ³Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via La Pira 4, 50121 Firenze, Italy — ⁴European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, 38043 Grenoble Cedex, France

Cu(In,Ga)Se₂ shows the highest conversion efficiencies of all thin film solar cells with more than 20%. It is believed that the formation of copper poor surface regions within the absorber is important for reaching these high efficiencies. The properties of the material, including the bandgap energy, are determined not only by the material composition and crystal structure but also by the local arrangement of atoms. Therefore, we studied the atomic-scale structure of Cu(In,Ga)Se₂ and the two copper poor phases Cu(In,Ga)₃Se₅ and Cu(In,Ga)₅Se₈ as a function of the In/Ga ratio using extended X-ray absorption fine structure spectroscopy. This yields the element-specific average bond lengths and bond length variations as a function of In/Ga ratio and Cu content thus providing a comprehensive picture of the relationship between local structural parameters and material composition.