Study of alternative back contacts for thin film Cu2ZnSnSe4-based solar cells

Souhaib Oueslati, Guy Brammertz, Marie Buffiere, Hossam ElAnzeery, Denis Mangin, Ounsi ElDaif, Oualid Touayar, Christine Köble, Marc Meuris, Jef Poortmans

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20 Citations (Scopus)

Abstract

Cu2ZnSnSe4 thin film solar cells are usually fabricated on a soda lime glass substrate with a molybdenum (Mo) back contact. It is suspected that degradation in electrical performance occurs due to the formation of a barrier between the absorber and Mo back contact. To overcome such degradation, Titanium Nitride (TiN), Titanium Tungsten (TiW), Chromium (Cr), Titanium (Ti) and Aluminum (Al) deposited on Mo-coated glass substrates are investigated as alternative back contact materials. Physical and electrical characterization as well as photoluminescence measurements are performed. Compositional analysis of the absorber layer on the metallized substrates identifies Mo, TiN and TiW as being the most inert during the formation of Cu2ZnSnSe4. On the other hand, Ti and Cr reacted with Se during selenization, thereby affecting the growth of the absorber, leading to low conversion efficiency. For Al, the absorber layer was etched after the standard potassium cyanide etch, hence, cannot be used as a back contact. The best device efficiencies obtained are 8.8% on TiN, 7.5% on Mo and 5.9% on TiW, respectively. The TiN back contact provides the lowest barrier value of about 15 meV which could be considered as a good ohmic contact.

Original languageEnglish
Article number035103
JournalJournal of Physics D: Applied Physics
Volume48
Issue number3
DOIs
Publication statusPublished - 28 Jan 2015
Externally publishedYes

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Keywords

  • Alternative back contact
  • CuZnSnSe
  • Ohmic contact
  • Solar cells
  • Thin film

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

Cite this

Oueslati, S., Brammertz, G., Buffiere, M., ElAnzeery, H., Mangin, D., ElDaif, O., Touayar, O., Köble, C., Meuris, M., & Poortmans, J. (2015). Study of alternative back contacts for thin film Cu2ZnSnSe4-based solar cells. Journal of Physics D: Applied Physics, 48(3), [035103]. https://doi.org/10.1088/0022-3727/48/3/035103