Effect of post-annealing temperature on structure and optical properties of Zn1-xCdxO thin films synthesized by magnetron sputtering

The Zn1-xCdxO (x = 0.5) thin film was grown on quartz by the direct current reactive magnetron sputtering and post-annealing techniques. The influence of annealing temperature (T-a) on the structure and optical properties of Zn1-xCdxO thin film was investigated by using X-ray diffraction (XRD), photoluminescence and optical absorbance measurements. The XRD results indicate that the as-grown Zn1-xCdxO thin film is of highly (002)-preferred orientation and possessing the hexagonal wurtzite structure of pure ZnO, as the T-a increases up from 300 to 600 degrees C, the phase segregation as cubic CdO was observed. The detailed microstructures of the Zn1-xCdxO thin film were investigated by transmission electron microscopy. Moreover, with the increase of T-a, the optical band gap of the Zn1-xCdxO thin films increased from 2.08 to 3.14 eV. Correspondingly, the near-band-edge photoluminescence was tuned in a wide visible region from similar to 588 to 403 nm.