Optical properties of europium-silicate thin films fabricated on different SiO_x intermediate layer

We report the effect of SiO_x intermediate layers on the photoluminescence properties of europium-silicate thin films. Layer structures of Eu₂O₃/SiO_x/Si (100) were deposited by using an rf-sputtering method and were annealed at 1100°C by rapid thermal annealing (RTA). Two methods were used for the deposition of the SiO_x layer: sputtering using a SiO₂ target (Ar gas at a rate of 50 sccm) and reactive sputtering using a Si target (Ar gas at a rate of 45 sccm with O₂ gas at a rate of 5 sccm). The photoluminescence peak at 430 nm was observed in the sample with a SiO_x interlayer sputtered from a SiO₂ target. In comparison, a PL peak at 570 nm was observed in the sample where SiO_x layer had been deposited by reactive sputtering from a Si target.