Process Research of Polycrystalline Silicon Material (PROPSM). Quarterly report No. 1, November 8-December 31, 1983

Abstract

Recent reported results of hydrogen-passivated polycrystalline silicon solar cells are summarized. Most of the studies have been performed on very small grain or short minority-carrier diffusion length silicon. Hydrogenated solar cells fabricated from this material appear to have effective minority-carrier diffusion lengths that are still not very long, as shown by the open-circuit voltages of passivated cells that are still significantly less than those of single-crystal solar cells. The short-circuit current of solar cells fabricated from large-grain cast polycrystalline silicon is nearly equivalent to that of single-crystal cells, which indicates long bulk minority-carrier diffusion length. However, the open-circuit voltage, which is sensitive to grain boundary recombination, is 20 to 40 mV less. The goal of this program is to minimize the variations in open-circuit voltage and fill-factor that are caused by structural defects by passivating these defects using a hydrogenation process.