Influence of substrate temperature on electrical and optical properties of p-type semitransparent conductive nickel oxide thin films deposited by radio frequency sputtering

Abstract: Nickel oxide thin films were deposited on fused silica and Si(100) substrates at different substrate temperatures ranging from room temperature to 400°C using radio frequency reactive magnetron sputtering from a Ni metal target in a mixture of O2 and Ar. With the increase of substrate temperature, nickel oxide films deposited on the Si substrates exhibit transition from amorphous to poly-crystalline structures with different preferred orientations of NiO(200) and (111). The films deposited at higher temperature exhibit higher Ni2+/Ni3+ ratio. With substrate temperature increasing from room temperature to 400°C, the electrical resistivities of nickel oxide films increase from (2.8±0.1)×10−2 to (8.7±0.1)Ωcm, and the optical band-gap energies increase from 3.65 to 3.88eV. A p-nickel oxide/n-zinc oxide heterojunction was fabricated to confirm the p-type conduction of nickel oxide thin film, which exhibited a steadily rectifying behavior. [Copyright &y& Elsevier]