Regensburg 2010 – scientific programme
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KR: Fachverband Kristallographie
KR 5: Topical Session Photovoltaic Materials I (with MM and BV MatWerk)
KR 5.3: Talk
Wednesday, March 24, 2010, 11:00–11:15, H4
Rigorous optical simulation of rough interface light trapping structures in thin film silicon solar cells — •Daniel Lockau1,2, Sven Burger2,3, Lin Zschiedrich2,3, Frank Schmidt2,3, and Bernd Rech1 — 1Helmholtz–Zentrum Berlin, Berlin, Germany — 2Zuse–Institut Berlin, Berlin, Germany — 3JCMwave GmbH, Berlin, Germany
Thin film silicon solar cells suffer from the disadvantage of a low absorption coefficient of silicon in important spectral regions. In the case of a flat multilayer cell layout a considerable part of the incident light is reflected back out of the cell due to the low absorber thickness. It is therefore desirable to introduce scattering elements that prolong the average photon path length inside the solar cell’s absorber. Rough interfaces between the layers of a solar cell have proven to provide efficient and industrially producible light trapping structures. As the scattering structures and the layer thicknesses are in the order of only a few ten wavelengths coherence effects have to be taken into account in the simulation and optimization of such structures.
We employ the finite element method for rigorous simulation of Maxwell’s equations on 2D and 3D geometries to investigate light trapping effects produced by rough interfaces in thin film silicon solar cells. To approximate an extended rough surface we examine the influence of boundary conditions and a finite computational domain size on the absorption. We apply Monte Carlo sampling over sets of surface representations to obtain averaged measurement quantities. Simulations of 2– and 3–dimensional rough surface geometries are compared.