Thin films of CuY1-xCaxO2 that are p-type conductors have been prepared by thermal co-evaporation. The films are polycrystalline on amorphous substrates and c-axis oriented on crystalline substrates. Calcium doping was necessary to produce conductive films, and the highest conductivity recorded was 1.0 S cm(-1). The average transparency in the visible region is approximately 40-50%, for conducting films approximately 250 nm thick, and in the infrared approximately 70% for a 350-nm conducting film. The optical spectra give evidence for a bandgap, of 3.5 eV. We have demonstrated an all-oxide p-n diode using CuY1-xCaxO2/Zn1-xAlxO.