Effects of deposition temperatures and substrates on microstructure and optical properties of sputtered CCTO thin film

Calcium copper titanium oxide (CaCu3Ti4O12, CCTO) films of 400 nm thickness were deposited on ITO and FTO substrates by radio-frequency (RF) magnetron sputtering at different deposition temperatures (100, 150, 200, and 250 °C). The influences of deposition temperatures and substrates on the structural, morphological, and optical properties of CCTO films were systematically investigated by XRD, AFM and UV-visible spectrophotometer. XRD study showed that all the CCTO films have a cubic structure. As the deposition temperature increased to 250 °C, the film crystallinity was improved, the crystallite sizes became larger and the films deposited on FTO substrates exhibited better crystalline quality. AFM studies revealed that the surface roughness of the films was increased with increasing deposition temperatures for both substrates. The transmittance spectra of the films were more than 50% transparent in the visible region (500-900 nm). It was also observed that the optical transmittance and energy band gaps reduced with increased deposition temperatures for both substrates.