Microstructural and Properties of P-type Nickel Oxide (NiO) Thin Films Deposited by RF Magnetron Sputtering

Nickel oxide (NiO) thin films were deposited on glass substrates using the RF magnetron sputtering technique at room temperature. The Argon and oxygen flow rates were kept constant at 10 sccm and 5 sccm respectively. The films were annealed at various temperatures (RT-300 °C) and its influence on the microstructural, optical and electrical properties were investigated. The X-ray diffraction (XRD) investigation of NiO films indicated the polycrystallinity of the films with the (111), (200) and (220) reflections corresponding to the cubic structure of NiO films. The crystallite size of NiO films was in the range ~4–14 nm. The transmittance of the films increased from 20 to 75% with increasing annealed temperature. The optical band gap of the films was 3.6–3.75 eV range for the as-deposited and annealed films. The Hall effect studies indicated the p-type conductivity of films and the film annealed at 300 °C showed higher carrier concentration (N), high conductivity (σ) and high mobility (μ) compared to other films. These NiO films can be used as a P-type semiconductor material in the devices require transparent conducting films.