N-Type conductivity of CuO thin films by metal doping

Abstract

Due to its unique electrical and optical properties, copper (II) oxide (CuO) potentially has a wide variety of applications. It is commonly known that CuO has p-type conductivity; however, we report observations of n-type conductivity in thin CuO films by metal doping for the first time. We achieved n-type electrical conductivity in CuO films with cobalt (Co) doping. Undoped and Co-doped CuO thin films were fabricated using a spin coating technique. Electrical parameters, specifically, the charge carrier concentration, sheet resistance, and conductivity type were investigated using a van der Pauw Hall measurement system. By 3 per cent of the cobalt doping conductivity type conversion was observed. The effects of metal doping on the width of the optical band gap were investigated using ultraviolet-visible spectrometry over the wavelength range of 300–1100 nm. The optical band gaps were found to be 1.43, 1.44, 1.44, 1.42 eV for un-doped, 2, 4 and 6% Co doped CuO thin films, respectively. The influence of different concentration ratio on the growth of CuO films was investigated using XRD. Microstrain (e), crystalline size (D) and dislocation density (δ) for all orientations were calculated from XRD analysis.