Influence of the growth rate on the morphology of electrodeposited zinc oxide

•We have grown ZnO thin films under a range of growth conditions by electrodeposition.•We demonstrate by three different ways that morphology is ruled by the growth rate.•We demonstrate that morphology strongly influences the layers optical properties.•The electrochemical parameters enable either a 2D or 3D growth mechanism.

We report on the electrodeposition of ZnO with different surface morphologies. We demonstrate by three different ways that morphology is ruled by the growth rate, and therefore strongly influences the optical properties of the layers. Whereas small size well-connected grains are obtained at high growth rate, the crystals evolve toward large disoriented nanorods since the kinetic of the reaction is hindered. The corresponding RMS roughnesses range from 35 nm to 119 nm, resulting in diffusion of the light from far UV to visible-wavelength. The surface morphology is shown to be directly mastered by electrochemical parameters which enable either a 2D or 3D growth mechanism.