Structural behavior and non-Debye dielectric response of copper doped Al:ZnO nanoparticles

In present work we have studied the copper and aluminium doped ZnO Al0.02Zn0.98-xCuxO nanoparticles by varying the concentration of copper from x = 0.00, 0.02, 0.04, 0.06. XRD, TEM, Raman spectroscopy and Rietveld's refinement was used for the study of doping effect on lattice parameters and bond length. Variation in lattice strain was compatible with the variation in lattice parameters. Ac electrical conductivity increases while dielectric constant decreases with the increase in frequency. Electrical conductivity was found to increase with the doping concentration, which was maximum for Al0.02Zn0.94Cu0.04O. Similarly, dielectric constant also increases with doping concentration and gives maximum value for Al0.02Zn0.94Cu0.04O. Almond-West equation fitted curves gives hopping frequency in the range of 1652 Hz–46,446 Hz. Relaxation time obtained from KWW fitting shows increasing trend with doping concentration of copper. It varies from 4.0✕10−5 to 5.6✕10−8 s.