Physical properties of copper oxide thin films prepared by dc reactive magnetron sputtering under different oxygen partial pressures

Nano-structured copper oxide thin films were deposited on glass substrates by dc reactive magnetron sputtering. The structural, morphological, electrical, and optical properties of the deposited copper oxide thin films were found to change with oxygen partial pressure. Changes in oxygen partial pressure during sputter deposition led to variations in Cu, Cu⁺ and Cu⁺² concentrations, which resulted in corresponding changes in the electronic characteristics of sputtered semiconducting copper oxide films from initially n- to p-type and then from p-type back to n-type. These phenomena demonstrate that p-type copper oxide thin films can only be deposited by dc reactive magnetron sputtering within a narrow oxygen partial pressure range.