X-Ray photoelectron spectroscopy and optical studies of Bi12(GaxBi1−x)O20−δ and Bi12(ZnxBi1−x)O20−δ single crystals

• Published in: The Journal of physics and chemistry of solids 1996-11, Vol.57 (11), p.1667-1672
• Main Authors: Zaldo, C., Coya, C., Fierro, J.L.G., Polgár, K., Kovács, L., Szaller, Zs
• Format: Article
• Language: English
• Subjects: A. optical materials; B. crystal growth; C. photoelectron spectroscopy; Condensed matter: electronic structure, electrical, magnetic, and optical properties; D. defects; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Infrared and raman spectra and scattering; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other nonmetallic inorganics; Other nonmetals; Other solid inorganic materials; Photoemission and photoelectron spectra; Photoluminescence; Physics; Visible and ultraviolet spectra
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/0022-3697(96)00036-4

Bi12(MxBi1−x)O20−δ transparent crystals, where M = Ga (x = 0.63 − 0.72)orM = Zn (x = 0.57), have been grown by Czochralski technique. A change in the bonding conditions of a minor fraction of bismuth in the sample surface has been confirmed by X-ray photoelectron spectroscopy. This has been attributed to the surface enhanced presence of bismuth in tetrahedral lattice positions (BiM). It is suggested that defect centers related with BiM cations are responsible for a pre-edge absorption observed for M = Ga. Excitation in this band produce a photoluminescence emission peaking at 608 nm, observed at 15K. Infrared absorption bands at 636 cm −1 for M = Ga and 635 cm −1 for M = Zn were detected and attributed to BiMO vibrations.