NOVELTY - The device has several tower structures (240) with a photovoltaic coating (260) along a top and sidewalls of each tower structure. The sidewalls of each tower structure have a surface roughness providing a selected level of scattering of light incident on the tower structures. Each tower structure has a conductive core material, a conductive layer (230) formed over a substrate (210), and a passivation layer (250) formed over the conductive layer. The conductive core material of each tower structure is coupled to the conductive layer.    USE - Three-dimensional photovoltaic device e.g. solar cell.    ADVANTAGE - Not only does the surface roughness of the tower structures increase the surface area of each tower structure, but also the light is absorbed and reflected additional times between the towers due to increased light scattering from the rough surface. The likelihood of energy conversion of a photon to a free electron is thus increased and the likelihood of light arriving at the surface of passivation layer and being reflected away from the three-dimensional solar cell is decreased. Thus improved efficiency of three-dimensional solar cells is realized by intentionally applying surface roughness to nano-scale tower structures of such solar cell. The surface roughness of each tower structure is enhanced to increase the surface area available for light gathering. Enhanced roughness is provided by manipulating passivation layer etching parameters used during formation process of the nano-scale tower structures, in order to affect surface roughness of photoresist layer used for the etch. Thus the nano-scale tower structure array having increased surface area on each tower for gathering incident light is provided for use in three-dimensional solar cells.    DESCRIPTION OF DRAWING(S) - The drawing shows an explanatory view illustrating structure of typical three-dimensional solar cell.    Substrate (210)    Conductive layer (230)    Tower structures (240)    Passivation layer (250)    Photovoltaic coating (260)    Light (270)