Light harvesting by planar photonic crystal in solar cells: The case of amorphous silicon

Guillaume Gomard (1) , Xianqin Meng (1) , Emmanuel Drouard (1) , Khalil El Hajjam (2) , Emmanuel Gerelli (1) , Romain Peretti (1) , Alain Fave (3) , Régis Orobtchouk (1) , Mustapha Lemiti (3) , Christian Seassal (1)

1 INL - Photonique - INL - Nanophotonique
2 INL - DE - INL - Dispositifs Electroniques
3 INL - PV - INL - Photovoltaïque

In this paper, we discuss on light management in silicon thin film solar cells, using photonic crystals (PhC) structures. We particularly focus on photovoltaic devices including amorphous silicon absorbers patterned as 2D PhCs. Physical principles and design rules leading to the optimized configuration of the patterned cell are discussed by means of optical simulations performed on realistic thin film solar cell stacks. Theoretically, a maximum 40%rel increase of integrated absorption in the a-Si:H layer of the patterned cell is expected compared to the unpatterned case. Moreover, both simulation and optical characterization of the fabricated cells demonstrate the robustness of their optical properties with regards to the angle of incidence of the light and to the fabrication induced defects in the PhCs. Finally, the impact of the surface recombination due to the generation of new free surfaces with higher defect densities is addressed. We demonstrate that patterning still induces a substantial increase of the conversion efficiency, with a reasonable surface recombination velocity.

Mots clés: photovoltaic solar cell; thin film solar cell; hydrogenated amorphous silicon; holographic lithography; photonic crystals

Domaines: Optique [physics.optics]; Sciences de l'information et de la communication

Guillaume Gomard, Xianqin Meng, Emmanuel Drouard, Khalil El Hajjam, Emmanuel Gerelli, et al.. Light harvesting by planar photonic crystal in solar cells: The case of amorphous silicon. Journal of Optics, 2011, 14 (2), pp.024011. ⟨10.1088/2040-8978/14/2/024011⟩. ⟨halshs-00834700⟩