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Title: Reversible order-disorder related band gap changes in Cu{sub 2}ZnSn(S,Se){sub 4} via post-annealing of solar cells measured by electroreflectance

We report on order–disorder related band gap changes in Cu{sub 2}ZnSn(S,Se){sub 4} solar cells which are induced by post-annealing. The band gap changes of the absorber are detected utilizing electroreflectance and analyzed by comparison with predictions of the stochastic Vineyard model. This yields a critical temperature of T{sub C}=195 °C above which the Cu{sub 2}ZnSn(S,Se){sub 4} absorber layer is entirely disordered within the Cu–Zn layers of the kesterite unit cell. The temporal evolution of the band gap during annealing shows that the equilibrium value is reached on a timescale in the order of hours, depending on the annealing temperature. In contrast to other experimental techniques, electroreflectance precisely measures the band gap and is not influenced by defect-mediated radiative recombination.
Authors:
; ; ; ; ;  [1] ; ;  [2] ;  [1] ;  [3]
  1. Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany)
  2. Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), 70565 Stuttgart (Germany)
  3. (ZSW), 70565 Stuttgart (Germany)
Publication Date:
OSTI Identifier:
22395611
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 26; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; COMPARATIVE EVALUATIONS; COPPER COMPOUNDS; CRITICAL TEMPERATURE; ELECTRONIC STRUCTURE; ENERGY GAP; EQUILIBRIUM; LAYERS; ORDER-DISORDER TRANSFORMATIONS; RECOMBINATION; SOLAR CELLS; SPECTRAL REFLECTANCE; STOCHASTIC PROCESSES; TIN SELENIDES; TIN SULFIDES; ZINC COMPOUNDS