Influence of thermal annealing on microstructural, morphological, optical properties and surface electronic structure of copper oxide thin films

Oxidation mechanism of thin Cu films: A gateway towards the formation of single oxide phase

“…46,47 In case of CuO, three peaks centered at 292, 341 and 626 cm -1 are observed, which can be identified as the first order A g and 2B g phonon scattering. 47,48 For thin films of mixed oxide phases Raman spectra show a combination of both set of peaks assigned to Cu 2 O and CuO. In general, the Raman spectroscopy results are in good agreement with our XRD findings and reveal a similar kind of phase transformation of the Cu 2 O to CuO during oxidation at a temperature above 320 • C. However, oxidation of the Cu films at a lower temperature, between 150 • C to 250 • C, Raman data reveals very different information in Thus, based on the Raman and the XRD analysis, it can be concluded that both Cu and Cu 2 O phases coexist within the oxidized films.…”

“…52,53 In XPS measurements the probing depth within the Cu oxide layer is expected to be only ∼2 nm for incident photon energy of 1486.6 eV (Al Kα line). 48,53 This makes XPS highly surface sensitive. Even though, the satellite peaks corresponding to the Cu +2 oxidation state are not observed for Cu 2 O film surface, which confirms the phase purity of the film.…”

Influence of annealing temperature on structural and optical properties of nanocrystalline Platinum octaethylporphyrin (PtOEP) thin films

“…The reduced amount of micro strain and dislocation density shows the formation of high quality PtOEP films at higher annealing temperatures. The thermal energy generated by annealing enhanced diffusion of species and formed films with larger crystallites [33,34]. Surface Morphology of the PtOEP films was analyzed by FESEM.…”

Spray Deposited Nanostructured CuO Thin Films: Influence of Substrate Temperature and Annealing Process

“…It seems that, among the factors which can possibly alter the band gap, the crystallite size of the CuO films are mainly responsible for the variation of the bandgap in this study. The correlation between crystallite size and band gap has been discussed earlier in literature 14,29 . Accordingly, by decreasing the crystallite size with increasing the substrate temperature, the band gap generally increased.…”

“…Among the spray deposition parameters, the substrate temperature and annealing temperature are the most common parameters optimized to obtain a thin film with desirable features. In the last decade, there has been several studies in which the influence of aforementioned factors has been investigated 13,14 ; yet in this study, CuO thin films have been deposited in high substrate temperatures starting from 450ºC and finishing at 550ºC in which the deposition rate declines drastically. It was found that, up to 525ºC, as the substrate temperature increases, the resistivity of the resulting CuO thin films decreases and again it increases for the film deposited at 550ºC.…”