Photoluminescence and wetting behavior of ZnO nanoparticles/nanorods array synthesized by thermal evaporation

By controlling the deposition rate of Zn atoms, we simultaneously synthesized ZnO particles on the upper surface of a horizontal silicon substrate, and ZnO rods array on its lower surface via a thermal evaporation process. The deposition rate of Zn atoms not only affects the morphologies of the final ZnO products, but also consequently leads to ZnO particles and ZnO rods array that have different photoluminescence properties and wetting behaviors. These two morphological ZnO products have just opposite relative intensities of UV emission to visible emission. ZnO rods array has a water contact angle of 160.3°, while ZnO particles film has a water contact angle of 150.4°, and their wetting behavior changed from the Cassie state to the Wenzel state during the process of droplet evaporation.

► ZnO nanoparticles and nanorods array grew simultaneously on both surfaces of a silicon substrate.
► The growth of two structures was controlled by the deposition rate of Zn atoms.
► Two ZnO structures have opposite relative intensities of UV emission to visible emission.
► Their wetting behavior changed with the evaporation of water droplets.