Nickel ion implantation effects on DC magnetron sputtered ZnO film prepared on Si (100)

Abstract This paper presents structural, optical and electrical properties of nickel ion (Ni + ) implanted ZnO film at different fluences. The ZnO films were grown on Si (100) using DC magnetron sputtering of pure zinc target at room temperature. The Ni + of energy 300 keV were implanted in the films at various fluences of 1.8 × 10 12 , 1.8 × 10 13 , 5.6 × 10 13 and 1.1 × 10 14 ions/cm 2 by Pelletron Accelrator. The ZnO films were found to be preferably oriented along (002) plane as indicated by the x-ray diffraction analysis. The Ni + implantation in ZnO up to 1.8 × 10 13 ions/cm 2 caused a decrease in the film's crystallinity, however, the crystallinity of the film was improved with further increase in the ion fluence. The surface morphology results revealed beans-shaped granular structure of ZnO that became prominent after ion implantation at lower ion fluence. The energy dispersive x-ray spectroscopy validated an increase in the nickel contents with increase of ion fluence. The ultraviolet–visible (UV–vis) reflectance spectroscopy depicted an increase in the film's band gap from 3.37 eV to 3.49 eV after Ni + implantation up to the fluence of 1.8 × 10 13 ions/cm 2 . However, the band gap was decreased with further increase in the fluence. The electrical resistivity of the film was measured using four probe technique. The resistivity was decreased from 952 to 68 Ω-cm after Ni + implantation up to 5.6 × 10 13 ions/cm 2 . However, at higher fluence (1.1 × 10 14 ions/cm 2 ), the resistivity was significantly increased.