Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 24: Photonic crystals II

HL 24.1: Vortrag

Dienstag, 26. Februar 2008, 09:30–09:45, EW 202

Direction selective filter using 3D photonic structures for ultralight trapping in solar cells — •Johannes Üpping, Andreas Bielawny, Paul T. Miclea, and Ralf Wehrspohn — Institut für Physik, Universität Halle-Wittenberg, Halle, Germany

We suggest a model to implement three dimensional photonic structures with direction-selective properties to be incorporated in solar cells. Our devices enhance the pathway of incident light within the solar cell in the spectral region of low absorption by restricting the reemission angle of the solar cell, this kind of light trapping we call ultra light trapping. Numerical studies of 3D photonic structures have been carried out with different numerical methods in order to find convenient structures. By matching photonic stop gaps of our device to the electronic bandgap of the cells semiconductor material, and with the orientation of the stop gaps high-symmetry axes around, but not in the direction of normal incidence, we inhibit the propagation of light selectively in angle and spectral distribution. At normal incidence, high transmission is provided because of another high symmetry axis of the photonic crystal. The result is a decrease in the allowed angle of reemission for the solar cell. A direction selective transmission calculation and corresponding microwave measurements show the ability of an inverted opal structure for ultra light trapping.