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

Abstract

Strontium barium niobate (Sr x Ba1–x Nb2O6, 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 °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.

Keywords

• Pockels
• electro-optical effect
• silicon photonics
• strontium barium niobate
• molecular beam epitaxy
• X-ray diffraction