The properties and structure of Ge-Se-Te glasses and thin films

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F17%3A39911078" target="_blank" >RIV/00216275:25310/17:39911078 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.jnoncrysol.2017.01.032" target="_blank" >http://dx.doi.org/10.1016/j.jnoncrysol.2017.01.032</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jnoncrysol.2017.01.032" target="_blank" >10.1016/j.jnoncrysol.2017.01.032</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The properties and structure of Ge-Se-Te glasses and thin films

Popis výsledku v původním jazyce

Ge30Se70-xTex bulk glasses and thin films for x = 0,10 and 20 were prepared. The properties and structure were characterized by differential scanning calorimetry (DSC), Raman spectroscopy and also by Se-77 and Te-125 MAS NMR spectroscopy. The optical properties were also measured. The absence of crystalline phases was verified by XRD, while DSC indicated that the glasses were not phase separated. Although the glass transition temperature of both Ge30Se70 glass and thin film is the same, different Delta C-p reveal a higher disorder of the thin film. Both the glass transition temperature and Delta C-p of Te glasses as well as crystallization temperatures decrease when Te increases due to increasing GeTe2/2 instead of GeSe4D structural units thereby reducing 3D interconnection of the glassy network. Based on the Se-77 MAS NMR results, the short-range order model was determined as a suitable structural model for Ge30Se70 glass. Se-77 and Te-125 MAS NMR confirmed that Ge in alloys with Te only reaches oxidation state +II in agreement with Ge Te phase diagram and therefore no GeTe4/2 tetrahedra can be present in these glasses and/or films. Raman spectroscopy confirmed that the short-range order of glasses and films is basically the same. The refractive index of thin films increases with tellurium content. The optical band gap of the thin films strongly decreases from 2.02 eV to 136 eV with increasing Te content and simultaneously the increasing structural disorder and width of the band tails increase. Reduction of the oxidation state of germanium to Ge&quot; caused by a reaction with tellurium ultimately leads to a reduction in 3D connectivity of the non-crystalline matrix and the loss of the glass-forming ability of the Ge Se Te system.

Název v anglickém jazyce

The properties and structure of Ge-Se-Te glasses and thin films

Popis výsledku anglicky

Ge30Se70-xTex bulk glasses and thin films for x = 0,10 and 20 were prepared. The properties and structure were characterized by differential scanning calorimetry (DSC), Raman spectroscopy and also by Se-77 and Te-125 MAS NMR spectroscopy. The optical properties were also measured. The absence of crystalline phases was verified by XRD, while DSC indicated that the glasses were not phase separated. Although the glass transition temperature of both Ge30Se70 glass and thin film is the same, different Delta C-p reveal a higher disorder of the thin film. Both the glass transition temperature and Delta C-p of Te glasses as well as crystallization temperatures decrease when Te increases due to increasing GeTe2/2 instead of GeSe4D structural units thereby reducing 3D interconnection of the glassy network. Based on the Se-77 MAS NMR results, the short-range order model was determined as a suitable structural model for Ge30Se70 glass. Se-77 and Te-125 MAS NMR confirmed that Ge in alloys with Te only reaches oxidation state +II in agreement with Ge Te phase diagram and therefore no GeTe4/2 tetrahedra can be present in these glasses and/or films. Raman spectroscopy confirmed that the short-range order of glasses and films is basically the same. The refractive index of thin films increases with tellurium content. The optical band gap of the thin films strongly decreases from 2.02 eV to 136 eV with increasing Te content and simultaneously the increasing structural disorder and width of the band tails increase. Reduction of the oxidation state of germanium to Ge&quot; caused by a reaction with tellurium ultimately leads to a reduction in 3D connectivity of the non-crystalline matrix and the loss of the glass-forming ability of the Ge Se Te system.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10402 - Inorganic and nuclear chemistry

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Non-Crystalline Solids

ISSN

0022-3093

e-ISSN

—

Svazek periodika

460

Číslo periodika v rámci svazku

March

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

9

Strana od-do

169-177

Kód UT WoS článku

000397835400022

EID výsledku v databázi Scopus

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