Effect of hydrogen plasma for spherical Si solar cells fabricated by high speed dropping method

The effects of hydrogen passivation on spherical Si solar cells are investigated. The spherical Si solar cells fabricated from Si spheres produced by a dropping method are multicrystalline Si including dislocations and grain boundaries. In order to inactivate the defects, H-passivation was done by R.F. plasma. The short circuit current density and the open circuit voltage of spherical Si solar cells increased after H-passivation, consequently, the conversion efficiency was enhanced. Current voltage characteristics and external quantum efficiency indicated the bulk passivation effect of recombination centers. Laser beam induced current analysis indicated that the crystal defects such as dislocations and grain boundaries were electrically inactive by H-passivation.