Structure and valence properties of ceria films synthesized by laser ablation under reducing atmosphere

Abstract : Film thicknesses, the oxidation state of metal and structural behaviour have important impacts on CeO2 film properties. CeO2 films have been deposited on Si substrates using pulsed laser deposition under various pressures of He–H2 gas mixture. A systematic study has been made regarding the influence of various parameters both on the surface composition and on the structure of the deposited films. The effects of the background pressure, the composition of the gas, the target–substrate and the radial distance have been studied. The most important parameter for the control of the Ce3+ content is the target–substrate distance. A distance of under five centimetres led to the formation of a poorly crystalline film with high Ce3+ content. A greater distance led to the formation of well crystallized CeO2 films.