Selenization of CuInS2 by rapid thermal processing an alternative approach to induce a band gap grading in chalcopyrite thin film solar cell absorbers?
| Autor: | Roberto Félix, H. Rodriguez-Alvarez, A. Weber, Marcus Bär, Roland Mainz, B.-A. Schubert, Regan G. Wilks, Ole Zander, Hans-Werner Schock, Joachim Klaer |
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| Rok vydání: | 2019 |
| Předmět: |
Methods and concepts for material development
Materials science medicine.diagnostic_test Renewable Energy Sustainability and the Environment Chalcopyrite Band gap Fermi level Analytical chemistry General Chemistry symbols.namesake X-ray photoelectron spectroscopy Rapid thermal processing visual_art Spectrophotometry visual_art.visual_art_medium symbols medicine General Materials Science Stoichiometry Ultraviolet photoelectron spectroscopy |
| Popis: | A treatment of CuInS2 (CIS) based on rapid thermal processing (RTP) selenization is developed, aiming at tuning the absorber's band gap grading using the [Se]/([S] + [Se]) composition. X-ray photoelectron spectroscopy and X-ray fluorescence analysis measurements of RTP-treated CIS samples (with the used set of RTP-parameter ranges) show a greater treatment effect at the surface of the sample compared to the bulk. A tuning of the [Cu] : [In] : ([S] + [Se]) surface composition from a Cu-poor 1 : 3 : 5 to a 1 : 1 : 2 stoichiometry is also observed in RTP-treated CIS absorbers with lower to higher surface Se contents, respectively. Ultraviolet photoelectron spectroscopy measurements show a shift in valence band maximum toward the Fermi level, EF, in higher surface Se content samples [from (−0.88 ± 0.1) to (−0.51 ± 0.1) eV], as expected for a reduction of the (surface) band gap produced by exchanging S with Se. Ultraviolet-visible spectrophotometry reveals a reduction in the optical (bulk) band gap of samples with greater Se incorporation [from (1.47 ± 0.05) to (1.08 ± 0.05) eV], allowing for a working window for optimization purposes. |
| Databáze: | OpenAIRE |
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