Wang, EWhite, T. P.Catchpole, K. R.2016-04-222016-04-221094-4087http://hdl.handle.net/1885/101099We numerically investigate the light trapping properties of two-dimensional diffraction gratings formed from silver disks or titanium dioxide pillars, placed on the rear of Si thin-film solar cells. In contrast to previous studies of front-surface gratings, we find that metal particles out-perform dielelectric ones when placed on the rear of the cell. By optimizing the grating geometry and the position of a planar reflector, we predict short circuit current enhancements of 45% and 67% respectively for the TiO₂ and silver nanoparticles. Furthermore, we show that interference effects between the grating and reflector can significantly enhance, or suppress, the light trapping performance. This demonstrates the critical importance of optimizing the reflector as an integral part of the light trapping structure.The authors would like to acknowledge the Australian Research Council, the Australian Solar Institute and the EU project PRIMA for their financial support. This work was supported by the NCI National Facility at the ANU.© 2012 Optical Society of AmericaKeywords: Integral part; Interference effects; Light trapping structures; Light-trapping; Metal nanoparticle arrays; Metal particle; Planar reflectors; Resonant enhancements; Silver nanoparticles; Thin-film solar cells; Two-dimensional diffraction gratings; Dielect2012-06-0410.1364/OE.20.0132262016-06-14