Influence of surface texture on the defect-induced breakdown behavior of multicrystalline silicon solar cells

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.