Anomalous Raman Modes in Tellurides

Two broad bands are usually found in the Raman spectrum of many Te-based chalcogenides, which include binary compounds, like ZnTe, CdTe, HgTe, GaTe, GeTe, SnTe, PbTe, GeTe2, As2Te3, Sb2Te3, Bi2Te3, NiTe2, IrTe2, TiTe2, as well as ternary compounds, like GaGeTe, SnSb2Te4, SnBi2Te4, and GeSb2Te5. Many...

Full description

Saved in:
Bibliographic Details
Published inarXiv.org
Main Authors Manjón, F J, Gallego-Parra, S, Rodríguez-Hernández, P, Muñoz, A, Drasar, C, Muñoz-Sanjosé, V, Oeckler, O
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 23.02.2021
Subjects
Bismuth tellurides
Cadmium tellurides
Chalcogenides
Chemical precipitation
Graphene
Intermetallic compounds
Laser beam heating
Lead tellurides
Oxidation
Precipitates
Raman spectra
Selenides
Selenium
Tellurium
Online AccessGet full text

Cover

More Information
Summary:Two broad bands are usually found in the Raman spectrum of many Te-based chalcogenides, which include binary compounds, like ZnTe, CdTe, HgTe, GaTe, GeTe, SnTe, PbTe, GeTe2, As2Te3, Sb2Te3, Bi2Te3, NiTe2, IrTe2, TiTe2, as well as ternary compounds, like GaGeTe, SnSb2Te4, SnBi2Te4, and GeSb2Te5. Many different explanations have been proposed in the literature for the origin of these two anomalous broad bands in tellurides, usually located between 119 and 145 cm-1. They have been attributed to the own sample, to oxidation, to the folding of Brillouin-edge modes onto the zone center, to the existence of a double resonance, like that of graphene, or to the formation of Te precipitates. In this paper, we provide arguments to demonstrate that such bands correspond to clusters or precipitates of trigonal Te in form of nanosize or microsize grains or layers that are segregated either inside or at the surface of the samples. Several mechanisms for Te segregation are discussed and sample heating caused by excessive laser power during Raman scattering measurements is emphasized. Finally, we show that anomalous Raman modes related to Se precipitates also occur in selenides, thus providing a general vision for a better characterization of selenides and tellurides by means of Raman scattering measurements and for a better understanding of chalcogenides in general.
ISSN:2331-8422