Surface Cleaning and Passivation Using (NH4)2S Treatment for Cu(In,Ga)Se2 Solar Cells: A Safe Alternative to KCN |
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| Authors: | Marie Buffière Abdel‐Aziz El Mel Nick Lenaers Guy Brammertz Armin E. Zaghi Marc Meuris Jef Poortmans |
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| Affiliation: | 1. Imec—partner in Solliance, Leuven, Belgium;2. Department of Electrical Engineering (ESAT), KU Leuven, Heverlee, Belgium;3. Institut des Matériaux Jean Rouxel, Université de Nantes, France;4. Department of Metallurgy and Materials Engineering (MTM), KU Leuven, Heverlee, Belgium;5. Imec division IMOMEC—partner in Solliance, Diepenbeek, Belgium;6. Institute for Material Research (IMO), Hasselt University, Diepenbeek, Belgium |
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| Abstract: | With the aim of developing a safe alternative to the KCN etchant for the removal of CuxSe secondary phases at the surface of Cu(In,Ga)Se2 (CIGSe) absorber, a method based on ammonium sulfide (AS) chemical treatment is proposed. Although lower etching rates are observed compared with the KCN reference solution, the AS solution is found to selectively etch CuxSe phases. In addition, it allows modifying the surface chemical state of the CIGSe absorber by incorporation of sulfur. As a consequence, the minority carrier lifetime located close to the surface of the absorber is found to be improved. Furthermore, it is demonstrated that optimizing the AS treatment time induces a remarkable enhancement in the electrical performances of the CIGSe‐based solar cells. |
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| Keywords: | alternative selective etchants chemical etching thin films secondary phases solar cells |
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