THE EFFECT OF MATERIAL INHOMOGENEITIES ON THE CHARACTERISTICS OF SEMICRYSTALLINE SILICON SOLAR-CELLS - THE 2ND DIODE

The effect of lateral variations in material properties on the I-V cha racteristic of semicrystalline silicon solar cells is studied by means of numerical simulation. Individual crystallites are described with t he aid of a one-diode model; the effective I-V characteristic of the c ell under illumination is analyzed in terms of a two-diode model using curve fitting. A wide distribution of diffusion lengths of the minori ty charge carriers is found to worsen the I-V characteristic. This is reflected in increased values of the effective series resistance and s econd-diode saturation current. The study shows that the effects of in trinsic inhomogeneities cannot be separated in a straightforward manne r from those of recombination in space-charge regions.