Structural and luminescent properties of YAG:Ce thin film phosphor

This work investigated the structural and luminescent properties of YAG:Ce (Ce-doped Y3Al5O12) thin films grown at different deposition conditions. The YAG:Ce phosphor thin films were deposited on quartz at room temperature by rf magnetron sputtering. It was shown that the oxygen partial pressure in the sputtering gas and the rf power strongly affected the Al/Y atomic ratio, growth rate, crystallinity and luminescent properties of YAG:Ce films. The effect of the O-2/(Ar + O-2) ratio on the composition prepared at RI differs from that prepared at high temperature. The growth rate of YAG:Ce films deposited at the gas ratio of O-2/(Ar + O-2) = 0% was significantly enhanced. Stoichiometric and polycrystalline YAG:Ce films were obtained in pure Ar. YAG:Ce films that were annealed in N-2 had a higher PL emission intensity than those annealed in air because annealing in N-2 prevents Ce3+ from the oxidation. We also found that transparency of YAG:Ce/quartz annealed at 1100 degrees C still was maintained, and YAG:Ce thin film has a transmittance of 75% including the substrate in the visible region. Annealing at temperatures above 1200 degrees C results in formation of SiO2 crystalline phase. The sample annealed at 1200 degrees C has much lower transmittance but higher PL intensity than those of the sample annealed at 1100 degrees C. (c) 2010 Published by Elsevier B.V.