Ga-induced defect engineering and charge transport mechanisms in ZnO ceramic materials

Abstract

Ga-doped ZnO (G3ZO) ceramics were successfully synthesized and their structural, electrical, dielectric, impedance, and relaxation properties were investigated to understand the effect of Ga incorporation on charge transport. X-ray diffraction confirmed the hexagonal wurtzite structure without detectable secondary phases. Williamson–Hall analysis showed a decrease in crystallite size from 51.7 nm for pure ZnO to 29.4 nm for G3ZO, while FE-SEM revealed agglomerated nanoparticles with an average particle size of about 38 nm. Electrical conductivity increased with frequency and temperature and followed Jonscher’s universal power law. The activation energy was 0.132 ± 0.007 eV, indicating thermally activated, defect-assisted charge transport. Impedance analysis showed a decrease in resistance with increasing temperature, while dielectric measurements revealed strong low-frequency dispersion associated with interfacial polarization. Electric modulus analysis indicated non-Debye relaxation behavior. Compared with pure ZnO, G3ZO exhibited improved electrical conductivity, dielectric response, and polarization, which can be related to Ga-related donor defects and increased charge-carrier concentration. These results demonstrate that Ga incorporation can effectively modify the structural and electrical properties of ZnO ceramics and may be useful for electronic and dielectric applications.