Abstract
ZnO layers were grown on SiO2 substrates by Chemical Bath Deposition (CBD) and characterized in terms of morphological, structural and local piezoelectric properties. The critical factors that allow the oriented growth of ZnO in nanorod configuration were carefully examined with a goal of getting close-packed <c>-oriented nanostructures for local piezoelectric measurements. After a first step consisting of creating ZnO-seeded layers on SiO2 substrates, the development of ZnO nanorods on these homo-buffer layers was more specifically studied through precursor concentration and growth time parameters. Morphological studies by X-ray diffraction and scanning electron microscopy illustrate that a suitable adjustment of these two factors (0.025M equimolar solution, 4h-dip coating) resulted in dense nanostructures with hexagonal wurtzite crystalline state. As-grown films exhibited a strong preferential out-of-plane orientation along the polar c-axis. Atomic force microscopy in contact mode (namely Electrostatic Force Microscopy or EFM) was used to determine the effective piezoelectric coefficient (d33) of such 1D-textured nanosystems. Values around 9.5 pm/V could be measured.