Special Presentation: Nicolas Vandamme, M.S. 2011

    Wednesday, June 4, 2014 - 10:00am - 11:00pm
    Franken Conference Room (Meinel 821)

    "Metal Nanogrids for Efficient Light Harvesting in Ultrathin GaAs Solar Cells"


    We discuss our design and fabrication of light-trapping schemes to absorb light efficiently in very subwavelength devices. With metal nanogrids, we induce resonant mechanisms such as Fabry-Perot and plasmonic resonators or excitation of guided modes via grating coupling. Resonance peaks –which can be tuned by modifying the geometrical parameters of the nanostructure – emerge in a multiresonant broadband absorption over the entire visible spectrum. A nanogrid is used on top of crystalline 25 nm-thick GaAs layer transferred by anodic bonding to form a metal-semiconductor-metal super absorber. Both numerically and experimentally, we achieve total absorption exceeding 80 percent over the 450-830 nm wavelength range. This is the broadest high-absorption spectrum for such an ultrathin crystalline semiconductor layer. Adapting this geometry to an ultrathin solar cell design leads to insertion of a nano-imprinted nanogrid on the back side of a 110-nm thick GaAs/AlGaAs heterojunction. Increased absorption drives the theoretical short circuit current up to 22mA/cm2 for the ultrathin device.

    Speaker Bio(s): 

    Nicolas Vandamme, M.S. 2011, performs research at the Laboratory for Photonics and Nanostructures at the National Center for Scientific Research in Marcoussis, France.