Host excitation-induced red emission from Pr 3+ in strontium barium niobate thin film

Abstract

Optical quality Sr x Ba 1− x Nb 2O 6 (SBN) thin films doped with Pr 3+ ions were successfully grown on fused quartz substrates using a pulsed laser deposition technique. Both as-grown and annealed samples were studied at either room temperature or at 10 K. Luminescence measurements show that most 4f 2→4f 2 emissions from Pr 3+ centers were efficiently quenched in the films. Strong red emission from 1D 2 to 3H 4 at ∼610 nm accompanied by weak emission to other 3H j multiplets could be observed only by UV excitation into the SBN conduction band. At 10 K, the main emission peak splits into four components. In addition, a broadband SBN-host luminescence was identified at ∼560 nm in the annealed sample, associated with the charge-transfer vibronic exciton. As an interstitial ion, Pr 3+ may occupy a 15-, 12-, 9- or 6-fold cage surrounded by oxygen and was found to occupy all four possible sites in SBN thin films. This behavior is different from Eu 3+- SBN where Eu 3+ only occupies a 6-fold site.