Influence of oxygen partial pressure on the structural, optical and electrical properties of Cu-doped NiO thin films

The NiO-Cu composite thin films were successfully deposited on Corning 7059 glass substrates at different oxygen partial pressures in the range of 9 x 10(-5)-6 x 10(-4) mbar using the dc reactive magnetron sputtering technique. All the deposited films were of polycrystalline nature and exhibited cubic structure with preferential growth. The optical transmittance and band gap of the films increased with increasing the oxygen partial pressure up to 2 x 10(-4) mbar and decreased on further increasing the oxygen partial pressure. From the surface morphological studies, fine and uniform grains were observed at an oxygen partial pressure of 2 x 10(-4) mbar. Compositional analysis indicated that Ni content increased and Cu content decreased with increasing the oxygen partial pressure. The resistivity values decreased gradually from 64 to 10 Omega cm with increasing the oxygen pressure to 6 x 10(-4) mbar.