CuO X thin films by direct oxidation of Cu films deposited by physical vapor deposition

Abstract Thin films of Cu 2 O and CuO oxides were developed by direct oxidation of physical vapor deposited copper films in an open atmosphere by varying the temperature in the range between 250 and 400 °C. In this work, the influence of oxidation temperature on structural, optical and electrical properties of copper oxide films has been discussed. The characterization results revealed that at lower temperatures ( d coper (I) oxide whereas at temperatures higher than 300 °C, the copper (II) oxide is formed. The band gap is found to vary in between 1.54 and 2.21 eV depending on the oxidation temperature. Both oxides present p-type electrical conductivity. The carrier concentration has been increased as a function of the oxidation temperature from 1.61 × 10 12 at 250 °C to 6.8 × 10 12  cm −3 at 400 °C. The mobility has attained its maximum of 34.5 cm 2  V −1  s −1 at a temperature of 300 °C, and a minimum of 13.8 cm 2  V −1  s −1 for 400 °C. Finally, the resistivity of copper oxide films decreases as a function of oxidation temperature from 5.4 × 10 6 to 2.4 × 10 5  Ω-cm at 250 and 400 °C, respectively.