@ A lightweight, photosensitive structure is formed on a electroplated substrate, characterized by a substantially reduced number of surface defects. The substrate is prepared in an electroforming process by electroplating it on and removing it from the surface of a specifically prepared, substantially defect-free mandrel. The substrate may be provided with a preselected surface finished by either texturing the mandrel or controlling the parameters of the electroplating process to determine the morphology of the deposit. The substrate is especially useful for the fabrication of thin film photoresponsive devices that incorporate specular or diffuse back reflectors, since the substrate surface texture may be controlled to provide for the appropriate type of reflectivity. Large-area, thin film semiconductor devices incorporating the electroplated substrate are readily scribed to form electrically isolated small-area segments for the fabrication of modules, arrays and the like.