N-type solar-grade silicon purified via the metallurgical route: characterisation and fabrication of solar cells

This study focuses on the characterisation and the fabrication of solar cells using n-type multicrystalline silicon purified via the metallurgical route. Electrical and chemical analyses were performed on wafers taken from several positions along the crystallised ingot. The impact of the fabrication processing steps was investigated via effective carrier lifetime measurements. Solar cells were processed, and their efficiencies were found to be dependent on the position of the wafer along the ingot height, that is, the wafer's resistivity. A maximum conversion efficiency of 15.0% was obtained on cells from the bottom part of the ingot. In this study, the minimum resistivity value of 0.4cm resistivity is given in order to reach adequate cell efficiency. Light-soaking experiments were then performed on the fabricated cells. No significant variations of the cell performances were observed even after 110h at 60 degrees C, meaning that the fabricated cells are stable under illumination. Copyright (c) 2012 John Wiley & Sons, Ltd.