Pulsed laser deposition and photoluminescence measurements of ZnO thin films on flexible polyimide substrates

In order to assess the potential of zinc oxide (ZnO) in flexible electronics applications, we created continuous ZnO films on polymeric substrates for evaluation of structural and optical properties. Specifically, we have used pulsed laser deposition to deposit ZnO films with thickness of several microns on flexible free-standing polyimide substrates. A KrF excimer laser (248 nm) operated at fluences of 3.0-6.2 J/cm2 was used. ZnO films were deposited at temperatures between room temperature and 300 °C under O2 atmosphere at a pressure of 50 Pa. Good flexibility characterizes the obtained layers and X-ray diffraction measurements show that films present all reflections of hexagonal ZnO. We discuss luminescence measurements on the films in relation to the complex interface phenomena expected in our samples.