The invention relates to a method of fabricating photovoltaic cells in which at least one layer of semiconductor material is deposited continuously on a carbon ribbon (10) to form a composite ribbon (20), said layer having a free face (22, 24) opposite from its face in contact with the carbon ribbon. According to the invention, at least one treatment (28) is applied to the layer of semiconductor material, from said free face (22, 24), in order to implement photovoltaic functions of the cells on said layer, prior to eliminating the carbon ribbon (10). The invention makes it possible to increase productivity in the fabrication of photovoltaic cells, which cells can be of very small thicknesses.