(US5279678-A)      A continuous and optically transmissive conductive layer is formed for electrically interconnecting photovoltaic cells while passing sunlight through the conductive layer to a photovoltaic junction. A first effective thickness is selected for an n-type polycrystalline semiconductor layer such that the thickness can be reduced to a second thickness passing a majority of sunlight energy having an energy higher than the bandgap of the n-type layer. A continuous n-type polycrystalline semiconductor layer is formed to the first thickness adjacent to the conductive layer.    A continuous p-type polycrystalline semiconductor layer adjoining the n-type polycrystalline layer forms a photovoltaic junction. The n-type polycrystalline layer and the adjoining p-type polycrystalline layer are heated to a temperature and for a time interval sufficient to reduce the first thickness of at least the n-type layer to the second thickness by diffusion of a portion of the n-type layer into the p-type layer, such that a majority of sunlight energy having an energy higher than the bandgap of the n-type layer passes through the reduced second thickness of the n-type layer to be absorbed by the photovoltaic junction.    ADVANTAGE -   N-type material layer of photoconductive junction is made highly transmissive to short wavelength energy reducing effective thickness of layer.    (JP8500209-W)      The method involves forming a continuous n-type semiconductor polycrystalline layer of a first effective thickness adjacent a conductive layer. A continuous p-type semiconductor polycrystalline layer is formed adjoining the n-type polycrystalline layers.    Both polycrystalline layers are simultaneously heated to a temperature for a time sufficient to significantly increase the size of the crystals within the p-type layer while substantially reducing the effective thickness of the n-type layer to substantially less than the first effective thickness by diffusion into the p-type layer.    ADVANTAGE -   Produces considerable increase in photovoltaic conversion efficiency, well suited for reliably controlling and enhancing regrowth of crystals and electrical properties of polycrystalline p-type layer and maintains highly controlled local stoichiometry of materials forming p-type layer.