The present invention provides a volumetric solar structure comprising one or more solar cells. The solar structure comprises a semiconductor substrate of a first conductivity type having a patterned surface thereof, the pattern defining an array of spaced-apart grooves of a funnel-like shape, and a second opposite conductivity type material layer positioned on at least a part of the patterned surface of the substrate. The structure thereby defines junction regions, in which charge carriers are generated by incident radiation energy to which the structure is exposed. The junction regions are located at different heights upon the patterned surface of the substrate.