Enhanced ferroelectric, dielectric and optical behavior in Li-doped ZnO nanorods

Enhancement in the dielectric and ferroelectric properties has been observed in case of Li-doped ZnO nanorods (NR). Effect of Li-doping on ZnO structure and its optical properties has also been reported. In high resolution TEM studies, the length and diameter of as-synthesized Li-ZnO nanorods were found in the range of 100-150 nm and 20-70 nm, respectively. XRD studies, Li-doped ZnO NR exhibited wurzite structure in which lattice parameter becomes larger than the pure ZnO NR. In dielectric studies, higher dielectric constant and a ferroelectric phase transition at 72 °C were observed. In ferroelectric studies, high remnant polarization of 0.873 μC/cm² and low coercive field of 0.592 kV/cm were observed, which were better than their values in bulk Li-doped ZnO (0.044 μC/cm² and 2.0 kV/cm, respectively). In UV-Vis spectra, low absorption band edge at 352 nm was observed due to the size effect in the ZnO nanorods. In addition, PL spectra show a blue shift in both UV and visible region as a result of doping. These results are discussed in the light of the nanorods of confined geometry.