Studies on optical and electrical properties of CdO/Al2O3 composites.

In the present communication, cadmium oxide (CdO)—alumina (Al₂O₃) nano–micro composites were prepared by addition of different amounts of nanostructured CdO in Al₂O₃ microstructured material. CdO was prepared by the sol-gel technique and Al₂O₃ was taken readily in micrometer scale. X–ray diffraction (XRD) results reveal the cubic structure of CdO and hexagonal structure of Al₂O₃. The nano and micro sizes of CdO and Al₂O₃ were confirmed by particle size analyzer, respectively. The microstructural properties and crystallinity of samples tested using FESEM and HRTEM with SEAD pattern analysis respectively. Energy band gap of the pure and composite materials has been estimated using the UV–Visible (UV–Viz) measurement. The dielectric, ac conductivity, and impedance behaviors of the materials were studied in the context of role of Al₂O₃ high resistive nature and conducting crystal boundaries of CdO nanoparticles. Space charge polarization for dielectric constant variation and correlated barrier hopping mechanism for ac conductivity behavior have been identified and discussed for all studied samples. Highlights: CdO nanoparticles were synthesized using sol–gel technique. Electrical properties of pure Al₂O₃, CdO20, CdO30, and pure CdO samples were studied. All the composites exhibit higher dielectric constant. Experimental data have been fitted by different models and mechanism. Theoretical models were employed to understand the responsible charge conduction. [ABSTRACT FROM AUTHOR]