Diffusion of aluminum, scandium and gallium ions into lithium niobate single crystals : Optical materials and their applications

Diffusion of aluminum, scandium and gallium ions in single crystals has been studied. Stoichiometric crystals have been grown by the Czochralski method using a double crucible and automatic powder supply system. Diffusant concentration profiles were measured by secondary ion mass spectrometry. The diffusivities of all ions depended on the Li/Nb ratio of single crystals. The diffusion coefficients were larger in the samples with lithium deficient composition than in that with stoichiometric composition. This behavior was explained by a cation vacancy model in the lithium niobate lattice