Investigations on electrical conductivity and dielectric properties of p-type ZnO by doping N synthesized from sol–gel method

This study investigated the effects of N doping on the structural, optical, dielectric and electrical properties for ZnO nanoparticles synthesized via a sol–gel method. X-ray diffraction revealed that all samples crystallized in the hexagonal wurtzite structure and crystallite size decreased from 30.36 to 26.18 nm with increasing N content from 0 to 20%. SEM analysis showed that undoped and N-doped ZnO nanoparticles exhibited roughly spherical shape and N doping had an effect on the size and distribution of the particles. The band gap energy for the samples determined by UV–Visible spectra gradually decreased from 3.24 to 3.15 eV with the N content increasing. XPS analysis confirmed N incorporation into ZnO nanocrystals and studied the nitrogen chemical bonding state. Impedance analysis exhibited a single semicircle for all samples, indicating grain boundary effects dominated over grain effects. Dielectric properties of ZnO were improved by doping N, the dielectric constant increased significantly from 35 to 330 at room temperature. Notably, 15% N-doped ZnO exhibits the largest dielectric constant while maintaining the lowest dielectric loss from 200–300 °C. These results suggest N-doped ZnO nanocrystals may be promising candidates for dielectric applications due to their tunable structural and dielectric properties.