Investigation of interface limited charge extraction and recombination in polycrystalline silicon solar cell: Using DC and AC characterization techniques

The present work reports an experimental study for the direct determination of broad range of performance indicating parameters of polycrystalline silicon solar cell by using direct current (DC) and alternating current (AC) characterization techniques. The DC characterization technique is employed to obtain the characteristic features of solar cell like fill factor, efficiency, series resistance and ideality factor. The AC characterization technique provides resolved electrical response of the resistances and capacitances of p-p+ (back surface field) and n+-p junctions, series resistance of the solar cell as well as the lifetime of minority charge carriers. The current density-voltage (J-V) characteristics demonstrate the existence of non-linear shunt paths and higher charge recombination for a less efficient polycrystalline silicon solar cell. The impedance spectroscopy results reveal that a low fill factor observed for less efficient silicon solar cell is due to the hindrance of charge carriers in active layer and low Fermi level degeneracy at Aluminium/Silicon (Al/Si) interface. The obtained DC and AC parameters and their underlying mechanisms are also examined using the proposed theoretical model. The results presented here demonstrate that the DC technique coupled with AC characterization technique can be quantitatively utilized for the investigation of unexplored fundamental and applied aspects of silicon solar cells.