NOVELTY - A photoelectrochemical cell comprises base conducting layer; wire arrays comprising oriented and ordered semiconductor wires, where the semiconductor wires have adjacent ends contiguous with the substrate, and distal ends oriented to receive incident light; and charge conducting layer, where portions of the charge conducting layer are in electrical contact with elongate semiconductor structures of along portions of the length dimensions of the semiconductor structures.    USE - A photocell for use in converting solar energy to electrical energy.    ADVANTAGE - The ratios, ordering, density and/or orientations of semiconductor structures with respect to incident light energy increases absorption of light while providing for efficient radial collection of carriers. The semiconductor structures orthogonalize the direction of light absorption with the direction of charge carrier collection, thus the structures have length dimensions in the direction of the incident light and width dimensions normal to the length dimensions. The cell have arrays of semiconductor structures with a regular ordering which provides increased numbers and increased density of structures for light energy reception.    DETAILED DESCRIPTION - A photoelectrochemical cell comprises base conducting layer; wire arrays comprising oriented and ordered semiconductor wires (940), where the semiconductor wires have adjacent ends contiguous with the substrate (910), and distal ends oriented to receive incident light, where the adjacent ends and distal ends define a length dimension for each semiconductor wire and where each semiconductor wire has a radius less than or equal to minority carrier diffusion lengths for material comprising the semiconductor wire; and charge conducting layer, where portions of the charge conducting layer are in electrical contact with elongate semiconductor structures of along portions of the length dimensions of the semiconductor structures. The elongate semiconductor structures absorb received light. The base conducting layer comprises a substrate, and the elongate semiconductor structures comprise structures grown from the substrate. An INDEPENDENT CLAIM is included for a photocell for conversion of water to hydrogen comprising photoanode comprising ordered wire arrays including elongate photoanode semiconductor wires, photocathode comprising ordered wire arrays including elongate photocathode semiconductor wires, and film electrically and ionically interconnecting the photoanode wires to photocathode wires.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a photoelectrochemical cell.    Substrate (910)    Electrolyte (930)    Semiconductor wires (940)