Ab initio and Raman study of medium range ordering in GeSe2 glass

Holomb, R.; Міца, В.; Akalin, Elif; Akyüz, Sevim; Sichka, M.

doi:10.1016/j.jnoncrysol.2013.04.032

Cited by 35 publications

(22 citation statements)

References 61 publications

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“…, and it should be noted that the peak at 125 cm −1 is the artificial peak due to the superposition of the decreasing flank of the background and the filter implemented in the FT apparatus. Raman spectra of the present ChGs correlate well with the spectra reported earlier from other Se–ChGs . The main peak can be assigned to the overlapping of the vibration modes of Ge–Se bonds (~195 cm −1 ) and Sn‐Se bonds (~184 cm −1 ) in corner‐shearing tetrahedral units.…”

Section: Resultssupporting

confidence: 86%

“…Raman spectra of the present ChGs correlate well with the spectra reported earlier from other Se-ChGs. [23][24][25] The main peak can be assigned to the overlapping of the vibration modes of Ge-Se bonds (~195 cm À1 ) and Sn-Se bonds (~184 cm À1 ) in corner-shearing tetrahedral units. The second largest band at~260 cm À1 is assigned to the characteristic vibration of Se-Se bonds in Se n chains or rings.…”

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confidence: 99%

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Correlating Structure with Threshold Behavior of Chalcogenide Glasses Within Ge–Sn–Se Ternary System

et al. 2016

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International audienceA systematic investigation of the optical and structural properties of chalcogenide glasses in Ge-Sn-Se ternary system is presented. We have found a threshold behavior of optical property, namely, existence of transitional composition of the Ge-Sn-Se glasses, with progressive replacement of Se by Sn. Calculation of mean coordination number indicates that the transition-like feature of optical property is associated with the evolution of chemical ordering of the Ge-Sn-Se network. Analysis of Raman spectra of the glasses explains that the interaction between Se-Se bonds, Sn(Se-1/2)(4) tetrahedra, and Sn-Sn homopolar bonds is the origination of such optical phenomenon

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Section: Resultssupporting

confidence: 86%

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confidence: 99%

Correlating Structure with Threshold Behavior of Chalcogenide Glasses Within Ge–Sn–Se Ternary System

et al. 2016

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“…The result of curve fitting of Raman spectra at 202cm -1 of Ge-Se cluster model of R. Holomb et al [35] indicates that, the peak located at ~ 204.1cm -1 is in very good accordance with the Raman mode at 204/205cm -1 calculated for six-membered rings and larger ring like Ge n Se m cluster topologically similar with the high temperature (HT) GeSe 2 .…”

Section: Raman Investigationsupporting

confidence: 64%

First Investigation of Optical Properties and Local Structure of Gd3+ Doped Nano-Crystalline GeSe2

Hantour¹

2016

AJOP

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Pure and Gd-doped nano-crystalline GeSe 2 were prepared by the melt-quenching technique. The crystal structure, local structure and emission properties are investigated. Structure analysis using Rietveld program suggests monoclinic structure for both virgin and doped samples with nano-particle size 41nm for GeSe 2 and 48nm for Gd-doped sample. A wide optical band gap as estimated from absorbance measurements is 4.1ev and 4.8ev for pure and doped samples in accordance with the confinement effects. Raman spectra show two unresolved components at ~ 202 cm-1 with broad line width. Also, well identified low intensity (ʋ < 145 cm-1) and high intensity (ʋ > 250 cm-1) bands are detected. For Gd-doped sample, the main band is shifted to lower energies and its FWHM is reduced by ~ 50% accompanied by an intensity increase of about ~ 17 fold times. The photoluminescence analysis of the pure sample shows a main emission band at ~ 604 nm. This band is splitted into two separated bands with higher intensity. The detected emission bands at wavelength > 650 nm are assigned to transmission from 6 G J to the different 6 P J terms.

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“…Poborchii and Kolobov [21,22] confirmed availability of Se-Se stretching mode in zeolite matrix, containing chalcogenide at vibrational bands way over the 250 cm À1 at 259 and 268 cm À1 . Furthermore, ab initio calculations show even the possibility for Se-Se vibrations to exist at 287 cm À1 [23]. However, although wrong bonds could be present always in the disordered systems and hence appearance of Se-Se bonds in the Ge rich composition is possible and is affecting the appearance of this vibrational mode, we suggest that in the regarded glass films the 270 cm À1 vibrational band is predominantly related to tetrahedral units containing Ge and Se, since one could not expect such a strong signal, as the one we obtained, originating primarily from wrong bonds.…”

Section: Resultsmentioning

confidence: 99%

X‐ray radiation induced effects in selected chalcogenide glasses and CBRAM devices based on them

Mitkova

Wolf

Belev

et al. 2015

Physica Status Solidi (b)

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Conductive bridge resistance change (CBRAM) memory devices are one of the premier emerging technologies for nonvolatile memory. The application of these devices could overlap possible situations where they are expected to perform in environments containing X-ray radiation. This poses the question, how X-ray radiation affects the materials comprised within these devices, as well as the performance of the CBRAM devices. In this work, we studied the structural changes caused by a wide range X-ray radiation over thin Ge-Se films with composition ranging from Se rich to Ge rich, as well as X-ray induced Ag diffusion within these films. The results show that after the cessation of radiation, the Ge rich films undergo considerable structural modification while the other compositions did not exhibit substantial changes. X-ray stimulated Ag diffusion with formation of Ag-Se by-products occurred predominantly in the Se and Ge rich films. These effects influence the performance of the CBRAM devices, based on these films and their I-V characteristics, threshold voltage and endurance are presented and discussed in the context of the materials characterization findings of this work, performed by Raman spectroscopy, Energy dispersion spectroscopy and X-ray diffraction. 1 Introduction The photoinduced effects in chalcogenide glasses (ChG) induced by exposure to visible and UV light are studied in depth and are well documented [1,2]. Similarly to visible light, X-rays can have indirectly ionizing effects on chalcogenide glass films. However, due to the shorter wavelength, the energy of the X-rays will be very high, leading to unique structural changes [3]. This for example, opens the opportunity for applying the effect of interaction of X-rays with chalcogenide glasses for the formation of X-ray flat panel image detectors [4,5]. Their performance is based on the absorption of X-ray photons by the chalcogenide photoconductor (usually a-Se) which facilitates the direct conversion of X-ray photons to electric charges. The studies, performed in relation with these X-ray induced effects of photocurrent in the chalcogenide films, resulted in the establishment of a charge trapping model for

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Ab initio and Raman study of medium range ordering in GeSe2 glass

Cited by 35 publications

References 61 publications

Correlating Structure with Threshold Behavior of Chalcogenide Glasses Within Ge–Sn–Se Ternary System

Correlating Structure with Threshold Behavior of Chalcogenide Glasses Within Ge–Sn–Se Ternary System

First Investigation of Optical Properties and Local Structure of <br/>Gd<sup>3+</sup> Doped Nano-Crystalline GeSe<sub>2</sub>

X‐ray radiation induced effects in selected chalcogenide glasses and CBRAM devices based on them

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Ab initio and Raman study of medium range ordering in GeSe2 glass

Cited by 35 publications

References 61 publications

Correlating Structure with Threshold Behavior of Chalcogenide Glasses Within Ge–Sn–Se Ternary System

Correlating Structure with Threshold Behavior of Chalcogenide Glasses Within Ge–Sn–Se Ternary System

First Investigation of Optical Properties and Local Structure of &lt;br/&gt;Gd&lt;sup&gt;3+&lt;/sup&gt; Doped Nano-Crystalline GeSe&lt;sub&gt;2&lt;/sub&gt;

X‐ray radiation induced effects in selected chalcogenide glasses and CBRAM devices based on them

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First Investigation of Optical Properties and Local Structure of <br/>Gd<sup>3+</sup> Doped Nano-Crystalline GeSe<sub>2</sub>