Structural and transport properties of CuSc1−xMgxO2+y delafossites

作者：Robert Kykyneshi, B. C. Nielsen, Janet Tate, J. Li, A.W. Sleight · 发表于：Journal of Applied Physics · 年份：2004 · DOI：10.1063/1.1806256 · 被引用次数：24 · 研究领域：Copper-based nanomaterials and applications、ZnO doping and properties、Electronic and Structural Properties of Oxides

Transport and structural properties of Mg-doped and O-intercalated sintered powders and polycrystalline films of CuSc1−xMgxO2+y are reported. Substitution of Mg for Sc systematically increases the p-type conductivity in CuSc1−xMgxO2 sintered powders, producing a maximum conductivity of 0.015S∕cm at x≈0.06. A similar level of conductivity is observed in transparent polycrystalline CuSc1−xMgxO2 films at the same doping level. Mg doping causes no significant increase in optical absorption at this level. Intercalation of oxygen into the delafossite structure leads to a much larger increase in p-type conductivity. In powders, the maximum conductivity is 0.5S∕cm at y=0.23 and x=0.05. In oxygen-intercalated films, the maximum conductivity was 25S∕cm, with the transparent films gradually darkening as oxygen is incorporated. Oxygen intercalation increases the a-axis lattice parameter of the delafossite structure in both films and powders, with a much smaller effect on the c-axis parameter. Two distinct phases with y≈0 and y≈0.5 are observed in x-ray diffraction of powders. In films intermediate values of y are observed, often in combination with a distinct y=0 phase. The absorption properties of the powder samples indicate introduction of defects into the 2H polymorph of CuScO2 and CuSc1−xMgxO2 compared to the 3R polymorph.