Optical properties of Ge:Sb:Te ternary alloys
| Autor: | Eduardo Morales-Sánchez, E. García-García, Jesús González-Hernández, Yu. V. Vorobiev, B. S. Chao, Arturo Mendoza-Galván, G. Martínez |
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| Rok vydání: | 1999 |
| Předmět: |
Materials science
Analytical chemistry Surfaces and Interfaces Condensed Matter Physics Spectral line Surfaces Coatings and Films Amorphous solid Condensed Matter::Materials Science Crystallography Electrical resistance and conductance Electrical resistivity and conductivity Ellipsometry Metastability Phase (matter) Ternary operation |
| Zdroj: | Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films. 17:1805-1810 |
| ISSN: | 1520-8559 0734-2101 |
| DOI: | 10.1116/1.581894 |
| Popis: | The complex dielectric function of the three stoichiometric compositions GeSb4Te7, GeSb2Te4, and Ge2Sb2Te5 has been measured by spectroscopic ellipsometry in the energy range of 1.4–5.1 eV. Each composition was measured in the amorphous and in the two crystalline states, the metastable face-centered-cubic and the stable hexagonal phases. The complex dielectric function shows strong differences between the amorphous and the crystalline samples, these differences are responsible for the drastic contrast in the reflectivity spectra. The ellipsometric spectra are fitted with models which fulfilling the Kramers–Kronig relations. Thus the Forouhi–Bloomer model was used for the amorphous samples and the Lorentz harmonic oscillator model for the crystalline samples. The temperatures at which the phase transformations are achieved were determined by measuring the ac electrical resistance at 100 Hz while the samples were heated. The temperature derivative of the electrical conductivity shows two well defined peaks at critical temperatures where the phase transformation occurs as is revealed by the x-ray data. |
| Databáze: | OpenAIRE |
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