Centered Symmetry Research Articles

The growth and properties of piezoelectric bismuth germanium oxide Bi 12GeO 20

Bismuth germanium oxide (Bi 12GeO 20) commonly reported as selenite or gamma bismuth trioxide has been grown as large single crystals by the Czochralski technique. The grown crystals are of body centered cubic symmetry and belong to the point group 23. The crystals are pale yellow in color with an index of refraction of about 2.55 and are transparent from 0.45 μm to 7.5 μm. Bismuth germanium oxide has been found to be strongly piezoelectric with a large electromechanical coupling constant, shows a large optical rotary power, electro-optic effects and exhibits photoconductivity.