Luminescent properties of pulsed laser deposition (PLD) thin films of SrGa2S4:Ce3+

The influence of different substrate temperatures on the morphological and optical properties of SrGa2S4:Ce3+ thin films prepared by the pulsed reactive cross laser ablation (PRCLA) technique has been investigated for application in flat panel displays. Auger electron spectroscopy (AES) depth profile analyses on the films were performed in order to measure the stoichiometric distributions of the deposited material as a function of depth. A depletion of S was obtained for the 600 °C substrate temperature sample. AES coupled with a cathodoluminescence (CL) spectroscopy system and X-ray photoelectron spectroscopy (XPS) was employed to measure the CL intensity and the CL intensity degradation as well as the surface chemical changes during and after exposure to 2 keV prolonged electron irradiation. The effect of different pressures on the degradation characteristics of the SrGa2S4:Ce3+ thin films ablated at 400 °C and 600 °C substrate temperatures was also investigated. The rate of degradation was observed to be slower in vacuum compared to oxygen. CL emission of Ce3+ was observed for the 400 °C sample and both the emissions of the 600 °C sample showed a red shift of about 32–33 nm, due to a change in the chemical composition and therefore a change in the crystal field. XPS results obtained for the film prepared at 600 °C substrate temperature suggest that a change in elemental bonding occurred during the degradation process.