Hydrogen passivation of grain boundaries in silicon sheet material

The impact of hydrogen passivation by means of ion implantation has been studied. The surface recombination velocity dramatically increases due to the passivation and connot be restored. This will limit high efficiencies in polycrystalline silicon solar cells. The passivation depth of both grain boundaries and the individual grains depend on the trap density of the material and on the diffusion profile of the hydrogen.