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Structural and Electronic Properties of Cu 2 MnSnS 4 from Experiment and First‐Principles Calculations
Author(s) -
Rudisch Katharina,
EspinosaGarcía William F.,
OsorioGuillén Jorge M.,
Araujo Carlos M.,
PlatzerBjörkman Charlotte,
Scragg Jonathan J. S.
Publication year - 2019
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201800743
Subject(s) - kesterite , band gap , annealing (glass) , materials science , raman spectroscopy , crystal structure , czts , thin film , crystallography , direct and indirect band gaps , extended x ray absorption fine structure , absorption spectroscopy , analytical chemistry (journal) , chemistry , nanotechnology , optoelectronics , metallurgy , optics , physics , chromatography
Cu 2 MnSnS 4 shares several promising properties with the widely investigated Cu 2 ZnSnS 4 for photovoltaic applications such as containing only earth abundant and non‐toxic elements, and suitable absorption characteristics for absorber materials. Thin film Cu 2 MnSnS 4 samples with various cation compositions are co‐sputtered reactively followed by a high temperature anneal. Formation of Cu 2 MnSnS 4 and co‐existence of several secondary phases is verified by XRD and Raman. Our investigation of the crystal structure based on first‐principles DFT confirms that stannite crystal structure is preferred over kesterite, although, further verification considering cation disorder is needed. The direct band gap of Cu 2 MnSnS 4 is calculated as 1.52 eV (1.62 eV) for stannite (kesterite), which coincides with the range of the measured band gaps from spectrophotometry of 1.42–1.59 eV. After further annealing treatments below 240 °C, the absorption shows reversible changes: the band gap blue‐shifts and the Urbach tail energy is reduced. It is concluded that, just like Cu 2 ZnSnS 4 , disorder also occurs in Cu 2 MnSnS 4 . The implications of our findings are discussed and related to the current understanding of cation disorder in Cu 2 ZnSnS 4 and related compounds. Furthermore, for the first time first‐principles DFT investigations are presented for the thiospinel Cu 2 MnSn 3 S 8 which is observed experimentally as a secondary phase in Sn‐rich Cu 2 MnSnS 4 thin films.