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.