Studies on copper oxide thin films prepared by simple nebulizer spray technique

Copper oxide films were deposited by simple nebulizer spray pyrolysis technique using aqueous solution of Copper(II) acetate monohydrate, high pure glucose and 20 vol% of 2-propanol. Structural, morphological, optical and electrical properties of the deposited films were characterized by XRD, Laser Raman, AFM, UV–Vis and Hall Effect measurements. The XRD study confirmed that the copper oxide films are in polycrystalline form of cuprous oxide (Cu₂O) phase with cubic crystal structure for the films deposited using precursor volumes of 3 and 4 ml, whereas the films deposited using 5 ml precursor solution are in cupric oxide (CuO) phase with monoclinic crystal structure. The higher concentration films shows higher thickness (~ 600 nm for 5 ml) and that change the phase/composition of the films. The prepared CuO films with 5 ml precursor solution are expected to show better properties. AFM studies revealed that the surfaces of the films are very smooth with uniformly distributed grains. The surface roughness of the film was increased with volume of the solution and the grain islands were coalesced with each other. UV visible spectrophotometer measurements showed that the band gap value of the prepared copper oxide thin films is varied between 1.63 and 1.23 eV due to change of volume of the solution. Hall Effect measurement showed that the prepared films are in p-type conductivity with 8.21 ×10² Ω-cm resistivity (ρ) and 12.56 ×10¹⁵ cm⁻³ carrier concentration (n) for the films prepared at 5 ml solution. All the studied properties of CuO for 5 ml precursor solution are remarkably changed.