Abstract
Direct current magnetron sputtering technique was used to synthesize ZnO films on PET (Polyethylene terephthalate) substrate. The as-synthesized films were exposed to 250 keV cobalt (Co) ions by Pelletron Accelerator at different ion fluences (in range of 1011 to 1014 ions cm−2). The lattice constant, crystallite structure, size and strain of pristine and Co-implanted films were studied through x-ray diffraction (XRD) method. The study showed that the ZnO film became partially amorphous after Co implantation up to the fluence of 1013 ions cm−2. However, Co implantation at 1014 ions cm−2 slightly restored the film's crystallinity due to ion-induced localized heating. Tauc equation was used to estimate the band gap of pristine and Co implanted films. The band gap of Co implanted ZnO was decreased by increasing the ion fluence that was ascribed to a decrease in the conduction band tail due to overlapping of donor defect levels. Electrical measurements showed that the ZnO film became more conductive with increasing the Co fluence.