Ion implantation of copper oxide thin films; statistical and experimental results

Abstract

Ion implantation is one of the interesting way to tune the electrical and optical properties of metal oxides. In this regard, doping copper oxide with nitrogen is of interest on account of its potential to enhance the properties of copper oxide. Herein, we have investigated the influence of nitrogen ion implantation on the properties of copper oxide thin films, prepared using DC magnetron sputtering. The crystal structure, surface morphology, and optical properties of pristine and ion implanted copper oxide were investigated by means of X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and UV–visible spectrophotometer. The results of XRD demonstrated a mixture of CuOCu2O and Cu2O (as dominant phase). Additionally, the ion implanted sample illustrated a lower grain compared to the pristine sample. An increase of 2–3 order was obtained in the internal strain upon implementation of nitrogen into the samples that could be ascribed to the formation of non-uniform grains and an increment in lattice imperfection.The results of surface micrographs demonstrated a remarkable change on the surface of samples and the appearance of interconnected holes after ion implementation. The band gap was tuned and increased from 2.27 to 2.36 eV upon ion implantation that is largely owing to the influence of the quantum size of copper oxide during implantation. Our results show that the nitrogen ion implantation (N-type doping) is a useful way to tune the properties of materials that are applicable for variety of photovoltaic and optoelectronic devices. Moreover, the 3-D surface micro-texture characteristics of pristine and nitrogen ion implanted copper oxide thin films were quantitatively investigated using AFM, fractal, and stereometric analyzes.