A master's dissertation was discussed in the College of Science, University of Mosul on preparing of three-layer solar cells with a study of their electrical and structural properties. The Dissertation aimed at preparing a solar cell consisting of three layers represented by a thin semiconductor membrane of zinc oxide (ZnO) with a very thin thickness, followed by a carbon layer with a Nano thickness ranging between 40nm_95nm, provided that this layer is built on bases of silicon slices from type p. The Dissertation demonstrated the structural properties of these prepared films, as well as studying of the structural properties as a diode and a solar cell at the same time. The Dissertation concluded a high response to the electric voltage and to the light shining on it, as they showed the properties of the diode with the forward and reverse biases and the results also showed that the added carbon layer that included carbon nanotubes played a major role in improving the properties of this structure as a diode and a solar cell.