Effects on the ZnO nanorods array of a seeding process made under a static electric field

The seeding process is a crucial step in achieving a homogeneous nanorods semiconductor layer by hydrothermal growth techniques. Previous studies have demonstrated the significant impact of the seeds on the morphology and orientation of these structures. In this study, we investigate the effect of a static electric field with values of 5 kV/m and 30 kV/m, applied during the seeding process to improve the vertical alignment of the resulting nanostructures that will grow over the seed layer. Due to the small size of the seeds and the c-axis dipole moment of ZnO, resulting nanoparticles are expected to have a dipole moment that interacts with a static electric field. In this work, we found evidence that this interaction promotes vertical alignment and also lateral growth of subsequent ZnO nanorods. This effect promotes, at the same time, a more compact growth of thicker nanorods at higher electric field values. The compactness increased from 21 % to 80 % and the transversal diameter from 91 nm to 150 nm. These interesting results are shown through X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectrophotometry and impedance spectroscopy (IS) characterization.