Piezoelectric, dielectric, optical and electrical characterization of solution grown flower-like ZnO nanocrystal

Flower-like ZnO nanocrystals were grown by low temperature solution technique after controlling Zn²⁺/OH⁻ ratio. The morphology and structural studies confirmed the formation of nano structure, revealing the [0001] oriented growth of the ZnO nanorods. The variation of dielectric constant, loss, ac conductivity and activation energy as a function of frequency was studied. In UV-Vis absorption spectra, a sharp absorption band-edge at 355 nm is observed from which direct optical band gap 3.40 eV was calculated. In P-E hysteresis piezoelectric characterization for unpoled ZnO, the value of remnant polarization and coercive field was found to be 16.31 µC/cm² and 6.11 kV/cm respectively which increased to 25.65 µC/cm² and 8.35 kV/cm, respectively after poling at 1 kV/cm. The piezoelectric charge coefficient (d₃₃) was found to be 1.7 pC/N.