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 × 1012, 1.8 × 1013, 5.6 × 1013 and 1.1 × 1014 ions/cm2 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 × 1013 ions/cm2 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 × 1013 ions/cm2. 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 × 1013 ions/cm2. However, at higher fluence (1.1 × 1014 ions/cm2), the resistivity was significantly increased.