NOVELTY - Producing a solar cell, comprises: obtaining a multi-crystalline substrate consisting essentially of doped metallurgical grade silicon doped as one of a p-type or n-type and having an upper side and an underside, the upper side for facing the sun; forming a first thin-film structure comprising an intrinsic silicon layer formed directly over and in direct contact with the upper side of the substrate; forming a second thin-film structure over first thin film structure; and forming top and bottom conductive contact.    USE - The method is useful for producing solar cells.    ADVANTAGE - The method: provides fabrication of silicon substrate, without need to perform gasification of silicon; provides fabrication of solar cell at low cost; is less hazardous and more environmentally friendly; and utilizing metallurgical-grade silicon wafers as substrate, thus the conversion efficiency is increases as compared to thin-film structures formed on glass.    DETAILED DESCRIPTION - Producing a solar cell, comprises: obtaining a multi-crystalline substrate consisting essentially of doped metallurgical grade silicon of 99.9-99.999% purity doped as one of a p-type or n-type and having an upper side and an underside, the upper side for facing the sun; forming a first thin-film structure comprising an intrinsic silicon layer formed directly over and in direct contact with the upper side of the substrate and a first doped layer of opposite polarity as that of the substrate and formed directly over and in direct contact with the intrinsic layer, to form a first p-i-n structure with the substrate; forming a second thin-film structure over the first thin film structure; forming a top conductive contact above the second thin film structure; and forming a bottom conductive contact on the underside of the substrate. An INDEPENDENT CLAIM is also included for fabricating a solar cell, comprising: obtaining a multi-crystalline substrate consisting essentially of doped metallurgical grade silicon of purity of 99.9-99.999% doped to a first type of conductance; forming a diffusion layer on top surface of the substrate such that the diffusion layer has opposite conductance of the first type; and forming a first thin-film structure over and in contact with the diffusion layer.