Influence of surface texture on the defect‐induced breakdown behavior of multicrystalline silicon solar cells. (18th January 2012)

• Record Type: Journal Article
• Authors: Kwapil, Wolfram; Nievendick, Jan; Zuschlag, Annika; Gundel, Paul; Schubert, Martin C.; Warta, Wilhelm
• Is Part Of: Progress in photovoltaics. Volume 21:Number 4(2013)
• Page Start: 534
• Page End: 543
• Publication Date: 2012-01-18
• Subjects: silicon solar cells -- multicrystalline -- defect‐induced diode breakdown -- surface texture -- etch pits; Solar cells -- Periodicals; Photovoltaic cells -- Periodicals; Solar power plants -- Periodicals; 621.31245
• DOI: 10.1002/pip.1226
• Languages: English
• ISSNs: 1062-7995

Abstract

ABSTRACT: The defect‐induced diode breakdown behavior in multicrystalline silicon solar cells, which is located at recombination active crystal defects, is influenced by the surface texturization because the wet chemical treatment selectively etches grain boundaries and dislocations, resulting in etch pits. On textured surfaces, the defect‐induced breakdown voltage is decreased, and the slope of the local reverse I–V characteristics in breakdown is steeper. We find that the local defect‐induced breakdown voltage correlates with the depth of the etch pits. It is suggested that the enhanced electric field in the space charge region at the tip could be superimposed by an electric field around metallic precipitates because of the internal Schottky contact formation with the surrounding silicon. The combined electric field could be responsible for the dependence of the defect‐induced breakdown behavior on the surface texture. Copyright © 2012 John Wiley & Sons, Ltd. Abstract : We show that the defect‐induced diode breakdown at recombination active defects of multicrystalline silicon solar cells strongly depends on the etch pit depth, the etch pits resulting from selective etching of crystallographic defects during the surface texturization. The deeper the etch pits are, the lower is the local defect‐induced breakdown voltage and the steeper is the increase of the reverse current locally flowing through defect‐induced breakdown regions with increasing reverse bias.