Growth of crystalline doped β-alumina thin films by laser ablation

Crystalline thin films of sodium beta-alumina and beta-aluminogallate, suitable for optical waveguides, were deposited onto various single-crystal substrates by the pulsed laser deposition technique. Films with a smooth surface morphology were obtained by using Cr-doped targets. Despite Na loss in the films with respect to the target composition, the beta-alumina crystalline phase was grown at elevated temperature (700-800 C), and highly textured (00l) films were obtained, whatever the substrates (MgO, ZrO2, Al2O3 or Si). The optical properties were studied by measuring the refractive index of the films and studying the emission spectra of the Cr3+ ions, providing results very similar to those of the bulk single-crystalline material. 12 refs.