Dielectric and electrical properties of Li-doped ZnO films

Li-doped ZnO films were prepared on Pt/TiO2/SiO2/Si substrates by using RF magnetron sputtering. The films were crystallized at temperatures above 400 .deg. C, which was confirmed by X-ray diffraction. The shapes of the grains changed from seed-like to rectangular as the annealing temperature was increased from 400 .deg. C to 700 .deg. C. The temperature dependence of the dielectric constant yielded a dielectric anomaly at 310 .deg. C. The ferroelectric polarization was measured using a polarization-electric field hysteresis loop. The leakage current density of the ZnO:Li films also displayed typical current-voltage characteristics, and the conduction mechanism was investigated for an applied electric field.