Effects of barrier metal, optical concentration, and grain boundary on polysilicon MOS solar cells

MOS solar cells have been fabricated with gold and silver as barrier metals on n-type and with aluminum as barrier metal on p-type Wacker cast polysilicon. The minimum thickness of the damaged surface layer needed to be removed by etching was found to be about 15 microns. For MOS cells, the barrier metal was found to have a stronger influence on the short-circuit current density and the series resistance than on the open-circuit voltage and the barrier energy in silicon. The grain boundaries in the Wacker material were found to have only a weak influence on the open-circuit voltage, the barrier in silicon, and the diode quality factor.