Enhanced absorption in thin crystalline silicon films for solar cells by nanoimprint lithography

Christos Trompoukis, Aline Herman, Ounsi El Daif, Valerie Depauw, Dries Van Gestel, Kris Van Nieuwenhuysen, Ivan Gordon, Olivier Deparis, Jef Poortmans

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    12 Citations (Scopus)


    Two dimensional (2D) periodic photonic nanostructures, fabricated by nanoimprint lithography (NIL) and dry etching on the front surface of crystalline silicon (c-Si) layers, are investigated experimentally and theoretically in order to characterize their optical properties and demonstrate their relevance to photovoltaic (PV) applications. Nanoimprint lithography is performed on c-Si wafers and ultra-thin c-Si films with various thicknesses. A comparison with state-of-the-art front side texturing with an antireflection coating is made. The 2D periodic photonic nanostructures result in an enhanced light absorption in the photoactive material. The results are validated through simulations based on Rigorous Coupled Wave Analysis (RCWA). The nanoimprinted substrates result in a similar absorption compared to the state-of-the-art random pyramid texturing while consuming less than a micron of photoactive material. In contrast to the random pyramid texturing, the nanopatterning exhibits a robust performance for a wide range of incident angles up to 70°. The light trapping mechanism we propose is based on the combination of a graded index effect and the diffraction of light inside the photoactive layer at high angles.

    Original languageEnglish
    Title of host publicationPhotonics for Solar Energy Systems IV
    Publication statusPublished - 12 Jun 2012
    EventPhotonics for Solar Energy Systems IV - Brussels, Belgium
    Duration: 16 Apr 201218 Apr 2012

    Publication series

    NameProceedings of SPIE - The International Society for Optical Engineering
    ISSN (Print)0277-786X


    OtherPhotonics for Solar Energy Systems IV



    • Anti-reflection texturing
    • Crystalline silicon solar cells
    • Diffraction
    • Light-management
    • Light-trapping
    • Photonic nanostructures
    • Thin-film silicon solar cells

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Computer Science Applications
    • Applied Mathematics
    • Electrical and Electronic Engineering

    Cite this

    Trompoukis, C., Herman, A., El Daif, O., Depauw, V., Van Gestel, D., Van Nieuwenhuysen, K., Gordon, I., Deparis, O., & Poortmans, J. (2012). Enhanced absorption in thin crystalline silicon films for solar cells by nanoimprint lithography. In Photonics for Solar Energy Systems IV [84380R] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 8438). https://doi.org/10.1117/12.921212