This works successfully synthesized vertically aligned, high density, long, large aspect ratio of CuO nanowires (CuO NWs) via thermal oxidation of copper (Cu) foil with atmospheric air. The oxidation process was conducted under temperature and time variation. The morphology and structure properties of CuO NWs were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. UV-Visible spectrophotometer was also used to estimate the direct band gap (1.75 eV) from the transmission spectrum. Furthermore, the film exhibit high absorption in the visible range and near infrared wavelength. The optimized parameters for long, small diameter, high density of CuO NWs at oxidation temperature of 500 °C for 6–8 h in the atmospheric air were found. The diameter and length of CuO NWs was determined within the range of 50–100 nm and 20–30 µm respectively. These optimized properties of CuO NWs make it a dependable candidate for visible light/near-infrared (NIR) photodetector fabrication. Therefore, the photodetector measurements were proved to render an acceptable performance.
