Surface cleaning and passivation using (NH4)2S treatment for Cu(In,Ga)Se2 solar cells: A safe alternative to KCN

Marie Buffiere, Abdel Aziz El Mel, Nick Lenaers, Guy Brammertz, Armin E. Zaghi, Marc Meuris, Jef Poortmans

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14 Citations (Scopus)


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.

Original languageEnglish
Article number1401689
JournalAdvanced Energy Materials
Issue number6
Publication statusPublished - 1 Mar 2015
Externally publishedYes



  • alternative selective etchants
  • chemical etching
  • secondary phases
  • solar cells
  • thin films

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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