Growth and Structure of Strong Pockels Material Strontium Barium Niobate on SrTiO3 and Si by Molecular Beam Epitaxy

Strontium barium niobate (SrxBa1-xNb2O6, referred to as SBN) is a material of interest for making efficient optical modulators due to its very high electro-optic (EO or Pockels) coefficient. SBN is a ferroelectric with a Curie temperature that varies between 20 and 80 degrees C, depending on its Sr/Ba ratio. Structurally, it belongs to the tetragonal tungsten bronze family. The successful integration of SBN on Si in textured epitaxial form using molecular beam epitaxy via a SrTiO3 (STO) buffer layer is reported. X-ray diffraction and scanning transmission electron microscopy are used to analyze the crystalline quality, STO/SBN interface structure, and preferred orientations of the SBN film. Thin, highly oriented SBN films integrated on Si have potential applications in low power and small footprint integrated Si photonics.