UV photoemission studies on PbTe, SnTe and GeTe in polycrystalline and amorphous phases

• Published in: Journal of the Physical Society of Japan Vol. 61; no. 3; pp. 1084 - 1097
• Main Author: FUKUI, K
• Format: Journal Article
• Language: English
• Published: Tokyo Institute of Pure and Applied Physics 01-03-1992; Physical Society of Japan; The Physical Society of Japan
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron density of states and band structure of crystalline solids; Electron states; Exact sciences and technology; Physics; Germanium Tellurides; Crystals; Lead Tellurides; Polycrystal; Amorphous state; Valence band; Experimental study; Inorganic compound; Ultraviolet radiation; Spectral line profile; Tin Tellurides; Covalent bond; Photoelectron emission
• DOI: 10.1143/JPSJ.61.1084
• EISSN: 1347-4073
• ISSN: 0031-9015

Photoemission spectra of PbTe, SnTe and GeTe in polycrystalline (c-) and amorphous (a-) phases have been measured with excitation photon energies between 16 and 80 eV. Three peaks in the valence band spectra are attributed to bonding p, cation s and Te s states. Widths of bonding p states suggest that the covalency is stronger in the order of PbTe<SnTe<GeTe in c-phase and in the order of SnTe<GeTe in a-phase, and the covalency is stronger in a-phase than in c-phase in the same material. From the spectral shape of constant-initial-state spectra of each initial state in the valence band, it is derived that excited states from the cation outermost d levels are localized but those from, Te 4d levels are not in c-IVTe's, while vice versa in a-GeTe. This also indicates that the covalency is stronger in a-phase than in c-phase.