Structural paradigm of Se-rich Ge–Se glasses by high-resolution x-ray photoelectron spectroscopy

Golovchak, R.; Shpotyuk, O.; Kozyukhin, S. A.; Kovalskiy, A.; Miller, A. C.; Jain, Himanshu

doi:10.1063/1.3130608

Cited by 48 publications

(79 citation statements)

References 34 publications

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“…Neutron-diffraction measurements and recent molecular dynamic simulations also suggests that the simple picture based on the <n> value is partially valid, as only about half of Se atoms are found in the predicted structural motifs 15,16 . The most recent studies imply that the structure a Ge-Se glasses significantly differs from the one predicted by the simple chain-crossing and outrigger raft models 17 , and very recent 77 Se NMR investigations evidence 18,19 the existence of Se-Se-Ge sites connecting GeSe 2 clusters and Se chains domains. However, whether the Ge-rich units are interconnected by means of Se chains…”

Section: Introductionmentioning

confidence: 99%

High-temperature elasticity and viscosity of GexSe1−xglasses in the transition range

et al. 2011

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Submitted to PRB July 14, 2010, revised Corresponding Author: Tanguy RouxelProfessor Tel: + 33-2-23236718Fax: + 33-2-23236111 E-mail: tanguy.rouxel@univ-rennes1.frThe viscous flow behavior and the temperature dependence of the elastic moduli of chalcogenide glasses from the germanium-selenium system were studied by means of homemade high temperature indentation setup and resonant frequency technique (1-10 kHz) respectively for temperatures between 0.8 and 1.2xT g . The softening rates, both in the elastic and in the viscous flow regimes, were correlated to network de-structuration or reorganization events in the light of previously reported high temperature neutron scattering data. The concomitant change of Poisson's ratio () and the thermodynamics parameters of the thermally activated viscous flow process, were characterized and provide a new basis for the understanding of the sources for the softening in the transition range. The temperature dependence of  suggests weak changes of the network cross-linking degree at large Gecontents. On the contrary, in the case of a-Se a steep fragmentation of the structural units is inferred from the (T) data and the flow process is accompanied by a huge entropy change (activation entropy at saddle point). The entropy contribution at T g (T g xS a ) represents more than 50 % of the activation enthalpy for flow (H a ) and increases with the selenium content.Hence the free activation energy (G a ) is much smaller than apparent activation energy as derived from viscosity data.

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Section: Introductionmentioning

confidence: 99%

High-temperature elasticity and viscosity of GexSe1−xglasses in the transition range

et al. 2011

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“…Recently, the paradigm of structural organization in the network Ge x Se 100-x glasses was explained well at the basis of high-resolution XPS [15]. In particular, it was shown (see Table 1) that two models could be adequately used to describe the structure of these materials, the so-called "chains crossing" and "outrigger raft" models.…”

Section: Resultsmentioning

confidence: 99%

“…1) [8,20]. According to [15], the structure of Ge x Se 100-x glasses with x < 12 is defined mainly by "chains crossing" model (within ~5-6 % accuracy bar), those with 12 ≤ x ≤ 20 by mixing "chains crossing" and "outrigger raft" models and, finally, the glasses with x > 20 are structured only by "outrigger raft" concept. This result is in good agreement with Raman scattering data showing formation of ES tetrahedra for glass compositions with x > 15 [21][22][23].…”

Section: Resultsmentioning

confidence: 99%

“…The recent results obtained with high-resolution X-ray photoelectron spectroscopy (XPS) [15] testify the specific structure formation within these compositions, which presumes constant ratio between edge-shared (ES) and cornershared (CS) GeSe 4/2 tetrahedra. It means that basic glassforming structural motive is more or less similar within the whole concentration range of the expected reversibility window, allowing only slight deviations in Se-based chains and rings.…”

Section: Introductionmentioning

confidence: 91%

“…It means that basic glassforming structural motive is more or less similar within the whole concentration range of the expected reversibility window, allowing only slight deviations in Se-based chains and rings. In the present paper, using quantum mechanics modeling and XPS data [15], we present a principally new approach confirming that self-organization in a sense of global glass connectivity is not possible in this binary Ge x Se 100-x system and previously reported 20 ≤ x < 26 compositional domain reflects only quasi-adaptive phases built of the overconstrained structural units interconnected via optimally-constrained bridges.…”

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

Cluster modeling of quasi‐adaptive phases in vitreous germanium selenides

Shpotyuk

Golovchak

Boyko

et al. 2010

Phys. Status Solidi (c)

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The developed cluster modeling approach based on ab‐initio calculations with RHF/6‐311G* basis set testifies absence of intermediate optimally‐constrained phase in binary Gex Se100‐x system within 20 ≤ x < 26 domain. It is shown, that character “outrigger raft” carcass is conserved for all glass compositions within expected reversibility window. Thus, the structure of binary Gex Se100‐x glasses can be described in terms of “chains crossing” model in case of x < 12, mixed “chains crossing” and “outrigger raft” models in case of 12 ≤ x < 20 and modified “outrigger raft” model in case of x ≥ 20. The expected reversibility window in binary Gex Se100‐x glasses is shown to be only quasi‐adaptive phase, based on “outrigger raft” structural motive with two edge‐ and four corner‐sharing tetrahedra interconnected by optimally‐constrained Ge‐Se‐Se‐Ge bridges with extra Se atoms in ring‐like configurations replaced Se‐Se dimers. The results of quantum mechanics modeling are confirmed well by high‐resolution X‐ray photoelectron spectroscopy measurements in this system. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Valence Band Structure of Chalcogenide Obtained by X‐Ray Photoelectron Spectroscopy and Etching Technique

Jia

Shi

Shen

et al. 2021

Physica Status Solidi (b)

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Chalcogenide glass, such as GeSe, has been widely used in the selector device for high‐density vertically stackable memory application due to their nonlinear electrical property. The electronic structure of the valence band, from which the nature of the bonding, the short‐range structure, and the Fermi level can be obtained, is of great importance to understand their unique electrical behavior. However, the surface oxidation issue makes it difficult to obtain the accurate valence band structure by X‐ray photoelectron spectroscopy (XPS). Herein, XPS depth profiles using the combination of the monatomic and cluster ion etching are performed to determine the valence band structures of amorphous Ge–Se films capped with a thin carbon layer. The completely different etching behavior dependent on composition in the depth profiles may be closely associated with the intrinsic bonding configurations of the amorphous films. After obtaining the fresh surface, the intrinsic valence band structures of amorphous Ge–Se samples demonstrate the different bonding behavior and short‐range structure. Most importantly, the Fermi level of amorphous GexSe100−x compounds is also determined.

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Structural paradigm of Se-rich Ge–Se glasses by high-resolution x-ray photoelectron spectroscopy

Cited by 48 publications

References 34 publications

High-temperature elasticity and viscosity of GexSe1−xglasses in the transition range

High-temperature elasticity and viscosity of GexSe1−xglasses in the transition range

Cluster modeling of quasi‐adaptive phases in vitreous germanium selenides

Valence Band Structure of Chalcogenide Obtained by X‐Ray Photoelectron Spectroscopy and Etching Technique

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