The Cu and Te coordination environments in Cu-doped Ge–Te glasses

Rátkai, László; Gonçalves, A.P.; Delaizir, Gaëlle; Godart, C.; Kaban, I.; Beuneu, B.; Jóvári, P.

doi:10.1016/j.ssc.2011.07.037

Cited by 16 publications

(31 citation statements)

References 23 publications

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“…However, at higher concentrations ( Z8% at.) Cu-Cu bonds are also formed, the coordination number of copper increases to N Cu 43 and the coordination number of tellurium is higher than 2, pointing that a significant percentage of tellurium atoms have three neighbors [14]. These studies also indicate that copper mainly occupies the free space of the host matrix, without strongly affecting the network of germanium and tellurium atoms [14].…”

Section: The Tellurium-based Semiconducting Glassesmentioning

confidence: 75%

“…This glass was reported as being composed by GeTe 4 tetrahedral units bridged by Te-Te bonds or shared tellurium atoms connected to two germanium atoms, with both germanium and tellurium obeying the 8-N rule [11][12][13][14]. A recent study on Cu-Ge-Te chalcogenide glasses based on Ge 20 Te 80 shows that glassy materials with copper concentrations as high as 27.5% at.…”

Section: The Tellurium-based Semiconducting Glassesmentioning

confidence: 99%

“…Structural studies indicate that at low concentrations ( o5% at.) copper has a coordination of $ 2, with only tellurium as next neighbor atoms, and germanium and tellurium continue obeying the 8-N rule [14]. However, at higher concentrations ( Z8% at.)…”

Section: The Tellurium-based Semiconducting Glassesmentioning

confidence: 99%

“…Cu-Cu bonds are also formed, the coordination number of copper increases to N Cu 43 and the coordination number of tellurium is higher than 2, pointing that a significant percentage of tellurium atoms have three neighbors [14]. These studies also indicate that copper mainly occupies the free space of the host matrix, without strongly affecting the network of germanium and tellurium atoms [14]. On the other hand, adding copper and decreasing the germanium concentrations result in a dramatically reduction (five orders of magnitude) of the electrical resistivity of the chalcogenide glass ( Fig.…”

Section: The Tellurium-based Semiconducting Glassesmentioning

confidence: 99%

See 3 more Smart Citations

Semiconducting glasses: A new class of thermoelectric materials?

Gonçalves

Lopes

Delaizir

et al. 2012

Journal of Solid State Chemistry

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Section: The Tellurium-based Semiconducting Glassesmentioning

confidence: 75%

Section: The Tellurium-based Semiconducting Glassesmentioning

confidence: 99%

Section: The Tellurium-based Semiconducting Glassesmentioning

confidence: 99%

Section: The Tellurium-based Semiconducting Glassesmentioning

confidence: 99%

See 2 more Smart Citations

Semiconducting glasses: A new class of thermoelectric materials?

Gonçalves

Lopes

Delaizir

et al. 2012

Journal of Solid State Chemistry

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“…Therefore, in this case Ag and I induce a strong rearrangement of the GeTe covalent network. On the other hand, in Ge-Ga-Te [4] and Te-rich Ge-Cu-Te [9] glasses the sum of Te-Te and Te-Ge coordination numbers remains close to 2 but the total coordination number of Te is significantly higher than 2, showing that modifying atoms form additional bonds with Te but do not rearrange the host network.…”

Section: Introductionmentioning

confidence: 93%

On the structure of Ge–As–Te–Cu glasses

Jóvári

Lucas

Yang

et al. 2016

Journal of Non-Crystalline Solids

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Short range order in glassy 0.9(Ge 0.1 As 0.15 Te 0.75 )-0.1Cu (GATC1) and 0.9(Ge 0.05 As 0.55 Te 0.4 )-0.1Cu (GATC2) was studied by neutron-and X-ray diffraction as well as EXAFS (extended X-ray absorption fine structure) measurements at the K-edges of all components. The reverse Monte Carlo simulation technique was used to create models consistent with all experimental datasets. It was found that Cu binds predominantly to Te in GATC1 while Cu-As and Cu-Cu bonding is also significant in GATC2. Ge and As atoms have 4 and 3 Ge/As/Te neighbors in both compositions. In GATC1 the formation of 'extra' Te-Te bonds can be observed, similarly to GeTe 4 -AgI glasses.

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Short‐Range Order Investigation of Cu_xGe_50−xTe₅₀ Phase‐Change Materials

Paulus

Stellhorn

Hosokawa

et al. 2022

Physica Status Solidi (b)

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The data storage stability and energy consumption of so-called phase-change materials (PCM) are determined by the stability of the amorphous and crystalline phases. The melting temperature T m of the crystal is a measure for the energy needed to transform from the crystalline to the amorphous phase. On the other hand, the stability of the amorphous phase is governed by the onset of crystallization at temperature T c . T m of the crystalline phase and the crystallization temperature T c are therefore important material properties.T m should be as low as possible to minimize power consumption and T c should be as high as possible to avoid spontaneous crystallization of the amorphous phase. [1] To optimize the stability of PCM materials towards long-lifetime storage applications, it is therefore crucial to understand the relationship between these parameters and the structural correlations in the amorphous phases.GeTe is a typical PCM which adopts at room temperature a distorted rock salt structure in which Ge is surrounded by three Te atoms with short bonds and three Te atoms with longer bonds. [2] Even though the crystalline phase is known for long, the amorphous phase is still subject of intense discussion. In the amorphous phase, the Ge atoms seem to be fourfold coordinated following the 8 À N rule. [3] Hence, the short range order between the two phases differs considerably. [4] The value of T c of the trigonal GeTe phase is %190 C. [5] As a PCM, it would therefore not be suitable for use at higher temperatures because the amorphous phase would no longer be stable. It was however found that substituting Ge atoms by Cu, to give Cu-Ge-Te compositions CGT Cu x Ge 50Àx Te 50 , enhances the crystallization temperature. [5] In this study CGT compositions are labeled by attaching the ratios of the elements Cu:Ge:Te (e.g., Cu 33 Ge 17 Te 50 equals CGT-213). Saito et al. investigated the phase-change characteristics for CGT compounds with different Cu contents. [5] They found an increasing T c up to 250 C at x % 15, while a further rise in Cu content leads to a decrease in T c . Compounds with lower Cu content, up to x % 20, crystallize into the GeTe structure. At higher Cu contents (26 ≤ x ≤ 38), they crystallize into the CGT-213 structure. [6] Saito et al. and also other authors point out that CGT-213 promises the best properties for PCM applications. Even though the T c of CGT-213 is lower than that for CGTs with less Cu

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The Cu and Te coordination environments in Cu-doped Ge–Te glasses

Cited by 16 publications

References 23 publications

Semiconducting glasses: A new class of thermoelectric materials?

Semiconducting glasses: A new class of thermoelectric materials?

On the structure of Ge–As–Te–Cu glasses

Short‐Range Order Investigation of Cu_xGe_50−xTe₅₀ Phase‐Change Materials

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The Cu and Te coordination environments in Cu-doped Ge–Te glasses

Cited by 16 publications

References 23 publications

Semiconducting glasses: A new class of thermoelectric materials?

Semiconducting glasses: A new class of thermoelectric materials?

On the structure of Ge–As–Te–Cu glasses

Short‐Range Order Investigation of CuxGe50−xTe50 Phase‐Change Materials

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Short‐Range Order Investigation of Cu_xGe_50−xTe₅₀ Phase‐Change Materials