Passivation of photonic nanostructures for crystalline silicon solar cells

Christos Trompoukis, Ounsi El Daif, Parikshit Pratim Sharma, Hariharsudan Sivaramakrishnan Radhakrishnan, Maarten Debucquoy, Valerie Depauw, Kris Van Nieuwenhuysen, Ivan Gordon, Robert Mertens, Jef Poortmans

Research output: Contribution to journalArticle

25 Citations (Scopus)


We report on the optical and electrical performances of periodic photonic nanostructures, prepared by nanoimprint lithography (NIL) and two different etching routes, plasma, and wet chemical etching. Optically, these periodic nanostructures offer a lower integrated reflectance compared with the industrial state-of-the-art random pyramid texturing. However, electrically, they are known to be more challenging for solar cell integration. We propose the use of wet chemical etching for fabricating inverted nanopyramids as a way to minimize the surface recombination velocities and maintain a conventional cell integration flow. In contrast to the broadly used plasma etching for nanopatterning, the wet chemically etched nanopatterning results in low surface recombination velocities, comparable with the state-of-the-art random pyramid texturing. Applied to 40-μm thick epitaxially grown crystalline silicon foils bonded to a glass carrier superstrate, the periodic-inverted nanopyramids show carrier lifetimes comparable with the non-textured reference foils (τ<inf>eff</inf>=250μs). We estimate a maximum effective surface recombination velocity of ∼8cm/s at the patterned surface, which is comparable with the state-of-the-art values for crystalline silicon solar cells.

Original languageEnglish
Pages (from-to)734-742
Number of pages9
JournalProgress in Photovoltaics: Research and Applications
Issue number6
Publication statusPublished - 1 Jun 2015
Externally publishedYes



  • advanced light trapping
  • minority carrier lifetimes
  • nanoimprint lithography
  • passivation
  • photonic nanostructures
  • surface recombination velocity

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Trompoukis, C., El Daif, O., Pratim Sharma, P., Sivaramakrishnan Radhakrishnan, H., Debucquoy, M., Depauw, V., Van Nieuwenhuysen, K., Gordon, I., Mertens, R., & Poortmans, J. (2015). Passivation of photonic nanostructures for crystalline silicon solar cells. Progress in Photovoltaics: Research and Applications, 23(6), 734-742.