Fabrication of Heterojunctions Based on Chemically Deposited Copper Oxide Thin Films for Solar Cell Application

Abstract

To fabricate the heterojunction, copper oxide (Cu₂O) layers were deposited by the chemical bath deposition technique using aqueous solutions containing CuSO₄ and Na₂SO₃ without and with adding a small amount of ethylendiamine (EDA). The counterpart of the heterojunction, i.e., a ZnO layer was deposited by electrochemical deposition. Indium-tin-oxide (ITO) coated glass sheet was used as a substrate, and both the substrate (ZnO/Cu₂O/ITO) and superstrate (Cu₂O/ZnO/ITO) structures were fabricated. The Cu₂O films were crystalline with a cubic crystal structure, had Cu/O ratios of 1.7 - 2, and consisted of octahedral particles, whose size was reduced by addition of EDA. The Cu₂O layers exhibited p-type conductivity and phtosensitivity. Rectification properties and week photovoltaic effects were observed for the heterojunctions fabricated using the solution with EDA.