Synthesis, characterization, and dielectricity performance of bulk pristine Fe3+ and Li+ Co-substituted wurtzite ZnO

High dielectric constant materials are of technological importance as they lead to the miniaturization of electronic devices. The permittivity of a material determines the relative speed that an electrical signal can travel in that material. The dielectric properties of pure ZnO are developed due to the defects of zinc excess at the interstitial position and the lack of oxidation. Fe and Li co-doping in ZnO are envisaged here to develop high dielectric materials by converting the material into a p-type semiconductor without creating stoichiometric oxygen defects in the lattice and making it robust against the oxidizing atmosphere. The formation of single-phase Fe and Fe/Li co-doped wurtzite ZnO samples is confirmed by X-ray diffraction analysis. The Fe and Fe/Li doping depresses the concentration of the intrinsic donor and impedes the conduction mechanism resulting in the highest dielectric constant (ɛ_r′) equivalent to 612 and 90,000 are found for bulk pristine Zn_0.9Fe_0.1O and Zn_0.8Li_0.1Fe_0.1O at 400^oC with 1000 ​Hz applied frequency. Also with an increase in frequency, the dielectric constant and dielectric loss are found to decrease. This behavior is attributed to different hopping mechanisms and defects formed during synthesis.