Atom probe tomography study of internal interfaces in Cu{sub 2}ZnSnSe{sub 4} thin-films

Journal Article · Mon Sep 07 04:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4929874· OSTI ID:22494839

Cojocaru-Mirédin, O.; Raabe, D. ^[1]; Mousel, M.; Redinger, A.; Siebentritt, S. ^[2]

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1. Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Strasse 1, 40237 Düsseldorf (Germany)
2. Laboratory for Photovoltaics, Physics and Materials Science Research Unit, University of Luxembourg, L-4422 Belvaux (Luxembourg)

We report on atom probe tomography studies of the composition at internal interfaces in Cu{sub 2}ZnSnSe{sub 4} thin-films. For Cu{sub 2}ZnSnSe{sub 4} precursors, which are deposited at 320 °C under Zn-rich conditions, grain boundaries are found to be enriched with Cu irrespective of whether Cu-poor or Cu-rich growth conditions are chosen. Cu{sub 2}ZnSnSe{sub 4} grains are found to be Cu-poor and excess Cu atoms are found to be accumulated at grain boundaries. In addition, nanometer-sized ZnSe grains are detected at or near grain boundaries. The compositions at grain boundaries show different trends after annealing at 500 °C. Grain boundaries in the annealed absorber films, which are free of impurities, are Cu-, Sn-, and Se-depleted and Zn-enriched. This is attributed to dissolution of ZnSe at the Cu-enriched grain boundaries during annealing. Furthermore, some of the grain boundaries of the absorbers are enriched with Na and K atoms, stemming from the soda-lime glass substrate. Such grain boundaries show no or only small changes in composition of the matrix elements. Na and K impurities are also partly segregated at some of the Cu{sub 2}ZnSnSe{sub 4}/ZnSe interfaces in the absorber, whereas for the precursors, only Na was detected at such phase boundaries possibly due to a higher diffusivity of Na compared to K. Possible effects of the detected compositional fluctuations on cell performance are discussed.

• OSTI ID: 22494839
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 118; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
COPPER
COPPER COMPOUNDS
GLASS
GRAIN BOUNDARIES
GRAIN GROWTH
IMPURITIES
INTERFACES
MATRIX ELEMENTS
POTASSIUM
PROBES
SELENIUM
SODIUM
SODIUM CARBONATES
THIN FILMS
TIN
TOMOGRAPHY
ZINC
ZINC SELENIDES