Influence of a-Si:H/ITO interface properties on performance of heterojunction solar cells

Raphaël Lachaume (1, 2, 3) , Wilfried Favre (2, 3) , Pascal Scheiblin (1) , Xavier Garros (1) , Nathalie Nguyen (2, 3) , Jean Coignus (2, 3) , Delfina Munoz (2, 3) , Gilles Reimbold (1)

1 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
2 DTS - Département des Technologies Solaires
3 INES - Institut National de L'Energie Solaire

In this study, we focus on the influence of the contact properties between Indium Tin oxide (ITO) and hydrogenated amorphous Silicon (a-Si:H) on the performance of a-Si:H/c-Si HeteroJunction (HJ) solar cells. We experimentally found that an increase of the (p) a-Si:H layer thickness can improve the open-circuit voltage (Voc) but also and especially the Fill-Factor (FF) of the cell. Thanks to simulation we propose an explanation of this unexpected increase. The deposition of ITO with low effective workfunction on (p) a-Si:H actually leads to a depletion of the emitter of the cell, which results in an increase of its effective activation energy and of its resistance affecting Voc and FF. Thanks to this new insight we give guidelines which can help to further optimize the HJ front stack.

Mots clés: heterojunction solar cells; transparent conductive oxide; indium tin oxide; hydrogenated amorphous silicon; contact; work function; simulation; optimization

Domaines: Micro et nanotechnologies/Microélectronique; Matériaux; Electronique

Raphaël Lachaume, Wilfried Favre, Pascal Scheiblin, Xavier Garros, Nathalie Nguyen, et al.. Influence of a-Si:H/ITO interface properties on performance of heterojunction solar cells. Energy Procedia, 2013, 38, pp. 770-776. ⟨10.1016/j.egypro.2013.07.345⟩. ⟨hal-01231749⟩