Novel syntheses of wide-band gap semiconducting Cdx Znx-1 Co2O4 of spinel nanostructure: Characterization and optical properties

Cadmium doped zinc cobaltite spinel structure in the form of Cd _x Zn _{x -1} Co ₂ O ₄ (0 ≤  x  ≤ 1) are synthesized by sol-gel method. A good crystallinity of the ZnCo ₂ O ₄ and its dopants samples are indicated by the sharpness and strong peaks of X-ray diffraction patterns. The particle size is independent of the ratio of incorporated Cd into the ZnCo ₂ O ₄ matrix. The FT-IR transmission spectrum of each Cd _x Zn _{1- x} Co ₂ O ₄ complex shows two strong vibration peaks that are ascribed to the spinel structure's octahedral and tetrahedral. The occurrence of light absorption by Cd _x Zn _{x -1} Co ₂ O ₄ is due to the photoexcitation of electrons from O 2 p to Co 3 d transitions and d - d transition of Co 3 d . The obtained values of the optical band gap ( E _g ) for Cd _x Zn _1-x Co ₂ O ₄ varies from 2.93 eV for ZnCo ₂ O ₄ ( x  = 0) to 2.15 eV for CdCo ₂ O ₄ ( x  = 1).