Structural, surface and optical investigations of Cu+ implanted NiO film prepared by reactive sputtering

摘要

? 2022 Elsevier Ltd and Techna Group S.r.l.Nickel oxide (NiO) films were deposited on silicon substrate using a DC magnetron sputtering system. The deposited films were annealed at 400 °C for 2 h and then irradiated by 500 keV copper ions (Cu+) in the dose range of 1 × 1011 to 1 × 1014 ions-cm?2 using Pelletron Accelerator. X-ray diffraction study revealed NiO and Ni phases in the films corresponding to (111) and (200) planes. The lattice parameter was increased with the increase of ion dose to 1 × 1012 ions-cm?2 and then decreased at the higher doses. Ion irradiation at 1 × 1011 ions-cm?2 improved the crystallinity of the film while at the higher doses, the crystallinity was decreased. The surface morphology of the films showed a decrease in the compactness of the granular structure with increasing the ion dose. Fourier Transform Infrared spectroscopy showed Cu–O and Ni–O stretching vibration peaks in the irradiated films. X-ray photoelectron spectroscopy (XPS) results revealed a decrease in Formula presented and increase in the Formula presented ratio with an increase of the ion dose to 1 × 1012 ions-cm?2, demonstrating an increase in the Ni vacancies in the film at lower doses. The depth-resolved XPS analysis displayed a change in the Ni and O atomic percentages in the film with the increase of the etching time from 50 to 250 s and validated the existence of metallic Ni in the NiO film. The photoluminescence (PL) spectra analysis showed a decreasing trend in the band gap of the NiO film irradiated up to 1 × 1012 ions-cm?2, then an increasing trend at the higher doses.