Electrical, optical and nonlinear optical process in spray pyrolyzed Zn:CuO nanostructures for optoelectronic device applications

Nanostructured pure and Zn doped CuO thin films were deposited on a glass substrate at 400 °C using the chemical spray pyrolysis method. The fabricated thin films were characterized to study the compositional, structural, morphological, optical and electrical properties. X-ray diffraction spectra show the polycrystalline nature of the sample and confirm the monoclinic phase of copper oxide. Raman analysis further confirms the absence of cuprous oxide phases and impurities. High absorbance in the visible region was observed for the films with bandgap values ranging from 1.7-2.0 eV. A near-band edge emission peak in the red region is recorded in the photoluminescence spectra. Uniformly distributed nanoparticles are observed in SEM images. Hall effect measurements indicate p-type conductivity and 5% Zn doped copper oxide showed the highest conductivity and carrier concentration. The non-linear absorption coefficient (β _eff) of the samples was obtained with the help of z-scan method with a Helium-Neon laser under the CW regime. Zn doping results in an increase in nonlinear absorption, supporting the use of Zn:CuO for optoelectronic devices.