Structural and electrical studies of Cu-doped CdO prepared by solid state reaction

This paper reports synthesis, crystal structure and electrical properties of Cu-doped CdO (CdO:Cu) powders. X-ray diffraction shows that majority of the samples are monophase and has the cubic structure. The limit solubility of Cu ions in CdO lattice is found to be 2 mol% (after heating at 900 °C), whereby the impurity phase was determined to be the monoclinic-CuO. For monophase CdO:Cu samples synthesized at 900 °C, the lattice parameter decreased with increasing Cu concentration. Electrical conductivity of undoped CdO and 2 mol% Cu-doped CdO (after heating at 900 °C) were found to be 79 and 191 Ω−1 cm−1, respectively, at 100 °C and 912 and 1549 Ω−1 cm−1, respectively, at 900 °C. Thus, it appears that electrical conductivity slightly increases with Cu doping. Finally, the activation energy of monophase CdO:Cu (after heating at 900 °C) is shown to decrease with Cu concentration.