Structural and electrical properties of Li-doped ZnO films

Zn1−xLixO films were spin-coated on platinum substrates by using sol-gel method. The XRD pattern demonstrated that the Li doped ZnO films exhibits the hexagonal wurtzite structure. And, the 18.5 ◦ peak was found at dopant content from 0.15 to 0.2, which could be attributed to the (003) plane of Li2PtO3. The effect of Li doping and emission in relation to defects is investigated using CL. Zn1−xLixO films show two characteristic emission peaks centered at near 383 nm and near 530 nm, respectively. The peak position of the UV emission is not changed when the Li content is increased from 0.0 to 0.2. The green emission peak increase abruptly at 0.1 Li content, however, decreases gradually with increasing Li content. The dielectric constant increases with increasing Li content up to 0.15, and decreases when lithium is added at 0.2. The ferroelectric polarization was measured using a polarization-electric field hysteresis loop. At x = 0.15, the measured values of spontaneous polarization and coercive field were 0.25 μC/cm2 and 1.6 kV/cm at room temperature, respectively.