Effect of laser annealing on ZnO nanorods grown by chemical bath deposition on flexible substrate

Integration of nanostructures of semiconducting materials such as zinc oxide with flexible substrates represent a great opportunity to obtain unique sensing platform especially for the biomedical market. However, the attractive optical and electrical properties of ZnO are usually obtained by growing or annealing nanostructured films at relative high temperatures (>400 °C), which are not suitable to substrates made of polymeric materials. We demonstrate in this work that high quality ZnO nanostructures can be processed at relative low temperature (<100 °C) by combining low temperature deposition process and XeCl excimer laser (wavelength 308 nm), used to locally anneal and recrystallize ZnO without affecting the underlying polymeric substrate. We obtain unique post-annealed ZnO nanostructures, grown and processed both on rigid and flexible substrates, that show comparable optical and structural properties of ZnO films that are processed at high temperatures. We discuss the effect of the laser energy density on the nanostructure by analyzing the recrystallized ZnO films through photoluminescence and scanning electron microscopy.