Copper Acetate Manufacturers(WSDTY) proposed optical transmission spectra of the films annealed at 800C and 900C are shown. The film annealed at 800C, which has the highest XRD peak intensity of c-axis orientated peaks, has a transparency of more than 60% at the wavelength longer than 500 nm region. In contrast, the film annealed at 900C shows lower transparency than the film annealed at 800C at longer wavelength than 400 nm, however, shows higher transparency at shorter wavelength. In addition, the absorption edge is blue shifted significantly compared with the film annealed 800C. The result indicates that the band structure of the films changed drastically between the annealing temperature 800C and 900C. A plot of (αhv)2 against the photon energy of the film annealed at 800C, and 900C, respectively. In the film annealed at 800C, the optical bandgap determined from the plot is 3.78 eV, which is higher than that of previously reported CuYO2 and the value is sufficiently high for use as a TCO material.
In contrast, the optical bandgap of the films annealed at 900?C is 5.27 eV, which is significantly higher than the film annealed at 800C. In addition, this result is inconsistent with the assignment by XRD that the film is oriented CuYO2 crystalline. It is considered that the film is consist of CuYO2 crystalline fraction and amorphous Y2O3 fraction that has bandgap of 5.6 eV. As mentioned previously, the fraction volume ratio of CuYO2 crystalline is thought to be low, thus, the optical bandgap of the film is thought to be determined by properties of the amorphous Y2O3 fraction that have significantly higher fraction volume ratio than CuYO2 crystalline in the film. The structural property dependency on the annealing temperature observed in the present work is not consistent with previously reported sol-gel preparation of CuYO2 films. It is because the synthesis of CuYO2 is directly from Cu-Y-gel, not from the Cu2Y2O5 that is promptly formed by the annealing of gel films in air before the annealing under nitrogen flow.
Click 8-hydroxyquinoline Copper to learn about more information