Combining ZnO inverse opal and ZnO nanorods using ALD and hydrothermal growth

Abstract

In this paper, we combine the atomic layer deposition synthesis method of inverse opal with the hydrothermal growth of nanorods. From 460 nm polystyrene nanospheres opal crystals were produced using vertical deposition on Si wafers. The opal templates were covered with ZnO by atomic layer deposition. High temperature annealing was used to remove the polystyrene nanospheres to obtain the inverse opal structure. For the hydrothermal growth of ZnO nanorods, two production routes were analysed: hydrothermal reaction before and after the removal of the template. The two paths produced two distinct structures, one with plate like formations and one with nanorods, respectively. Also, the sample modified by the hydrothermal growth after the annealing showed slight differences in optical properties compared to the regular inverse opal. Morphology, composition and structure of the samples were explored using SEM, EDX and XRD. Optical properties were investigated with reflectance UV–Vis spectroscopy. Thermal stability of the polystyrene opal was determined using TG.