Synthesis of the p-type semiconducting ternary oxide CuAlO2 using the Pechini method

The synthesis of the delafossite phase CuAlO2 using the Pechini method was investigated. Powder X-ray diffraction data showed that pure, single-phase samples were obtained after only 3 h heating at 1100 °C. CuAl2O4, which contains Cu(II) rather than Cu(I), was the dominant phase between 700 and 1100 °C. Conversion to CuAlO2 is promoted by the positive entropy change associated with the evolution of oxygen. No mixed Cu–Al oxide was formed below 700 °C.