Abstract: The invention relates to techniques for manufacturing columnar-grained polycrystalline sheets which have particular utility as substrates or wafers for solar cells. The sheet is made by applying granular silicon to a setter material which supports the granular material. The setter material and granular silicon are subjected to a thermal profile all of which promote columnar growth by melting the silicon from the top downwardly. The thermal profile sequentially creates a melt region at the top of the granular silicon and then a growth region where both liquid and a growing polycrystalline sheet layer coexist. An annealing region is created where the temperature of the grown polycrystalline silicon sheet layer is controllably reduced to effect stress relief.

Abstract: A plurality of thin polycrystalline silicon solar cells formed on a ceramic substrate and which are electrically series connected to form a monolithically interconnected submodule. Adjacent solar cells are electrically separated by a vertical trench and electrically connected by interconnects located below the light receiving surface of each solar cell. The submodules are provided with external electrical contacts for electrically connecting into a photovoltaic module assembly.

Abstract: A thin-film photovoltaic solar cell features a thin polycrystalline silicon active semiconductor formed over a conductive ceramic substrate. Between the substrate and the adjacent active semiconductor layer is a barrier layer which provides for reflection of light, minimizes back surface recombination and prevents contamination of the active semiconductor.