The system Ge-Se-Te and the preparation and properties of the new non-stoichiometric compound GeSe0.75Te0.25

Muir, James A.; Cashman, R. J.

doi:10.1016/0022-3697(67)90218-1

Cited by 23 publications

(13 citation statements)

References 11 publications

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“…Between a-GeTea nd a-GeSe,t here is as upposedly hexagonal phase for GeSe 1Àx Te x with 0.1 x 0.5, [8] firstf ound in the 1960s by Muir and Cashman. [9] Although crystal growth by chemical transport was mentioned, the full structure has remained unknown to date.W eherein describe the growth of single crystals of Ge 4 Se 3 Te and its refined crystal structure, revealing as eemingly two-dimensional (2D) material with van der Waals type interactions and initially unexpected Ge-Ge contacts.…”

Section: Dedicated To Professor Roald Hoffmann On the Occasion Of Hismentioning

confidence: 99%

Unexpected Ge–Ge Contacts in the Two‐Dimensional Ge₄Se₃Te Phase and Analysis of Their Chemical Cause with the Density of Energy (DOE) Function

et al. 2017

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A hexagonal phase in the ternary Ge-Se-Te system with an approximate composition of GeSe Te has been known since the 1960s but its structure has remained unknown. We have succeeded in growing single crystals by chemical transport as a prerequisite to solve and refine the Ge Se Te structure. It consists of layers that are held together by van der Waals type weak chalcogenide-chalcogenide interactions but also display unexpected Ge-Ge contacts, as confirmed by electron microscopy analysis. The nature of the electronic structure of Ge Se Te was characterized by chemical bonding analysis, in particular by the newly introduced density of energy (DOE) function. The Ge-Ge bonding interactions serve to hold electrons that would otherwise go into antibonding Ge-Te contacts.

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Section: Dedicated To Professor Roald Hoffmann On the Occasion Of Hismentioning

confidence: 99%

Unexpected Ge–Ge Contacts in the Two‐Dimensional Ge₄Se₃Te Phase and Analysis of Their Chemical Cause with the Density of Energy (DOE) Function

et al. 2017

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“…An analogous activation energy occurs in the resistivity, and is mainly responsible for the temperature dependence of the resistivity. 2 This activation energy has not previously been thought to be strongly affected by a magnetic field. 3 Thus in a magnetic field the resistivity would have a temperature dependence similar to that when H-0, and p/po would be expected to be almost temperature-independent.…”

mentioning

confidence: 87%

“…2 The crystals grow in the form of thin plates with the c-axis perpendicular to the plates. Relatively thick (1-10 /x) crystals were used in the region of low absorption, while much thinner ones…”

Section: Acknowledgmentsmentioning

confidence: 99%

Magnetically Induced Spin-Reversal Transitions in Impurity Hop Conduction inn-Type Germanium

1968

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At high magnetic fields (45-146 kG) the magnetoresistance p/po of hop conduction in w-type germanium is found to have a temperature dependence which increases with field strength. It is shown that phononassisted tunneling with reversals of spins of electrons while they make interdonor transitions can account for this effect. Spin reversals are caused by strong coupling of phonon shear waves with spins of electrons in donor ground states in the presence of the magnetic field. An expression for the probability of the interdonor transition with spin flip is obtained by modifying the ordinary spin-lattice relaxation theory to apply to a two-donor system. The modification follows the theory for phonon-assisted spin-conserving electron tunneling between donors.GeSeo.75Teo.25 is a new IV-VI compound which has electrical properties similar to those of the degenerate semiconductors GeTe and SnTe. Optical absorption has been measured in single crystals of GeSeo.75Teo.25 grown by an iodine transport process. The measurements show a sharp absorption edge followed by a rapid rise in absorption at long wavelengths caused by the large free-carrier concentration (10 20 holes cm" 3 ). The absorption edge is interpreted as the fundamental absorption edge of a semiconductor. It is concluded that GeSeo.75Teo.25 is a degenerate semiconductor which has a band gap considerably less than 0.82 eV.

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“…Electrical measurements on GeTe, crystallized from stoichiometric ratios of the components, indicate that the solubility of the elements in GeTe are up to 1 atom% Ge and 4 atom% Te [9]. For the mixed compound GeSeo.75Teo.zS [13], a deviation from stoichiometry of 0.2 atom% was derived from carrier concentration measurements. Thermal expansion studies of GeTe showed that the room temperature rhombohedra1 structure transforms to a NaC1-type cubic structure at 375 "C [14].…”

Section: Introductionmentioning

confidence: 99%

“…The complex phase equilibria of the pseudo-binary GeSe-GeTe mixed system have been investigated in parts in various studies [13,17,18,191 leading to partly contradictory results. For GeSexTel-, compounds (0 < x < 0.1) the existence of two low temperature modifications with various deviations from stoichiometry were reported [20].…”

Section: Introductionmentioning

confidence: 99%

Physical vapor transport and crystal growth of GeSe_xTe_1−x solid solutions

Wiedemeier

1991

Zeitschrift anorg allge chemie

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Physical vapor transport studies of GeSexTe1–x (x = 0.1, 0.2, 0.3, and 0.4) solid solutions demonstrated, that individual, large single crystals of these materials can be grown in closed ampoules. A compositional analysis of the grown crystals revealed, that the mass transport (crystal growth) process under steady‐state conditions is pseudo‐congruent and controlled by diffusion processes in the source material. From these experiments, the degree of nonstoichiometry (Ge‐vacancy concentrations) of GeSexTe1–x single crystals could be estimated. The effects of the cubic to rhombohedral phase transformation during cooling on the microstructure and morphology of the grown mixed crystals are observed. This work provides the basis for subsequent defect studies and electrical measurements on these crystals.

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The system Ge-Se-Te and the preparation and properties of the new non-stoichiometric compound GeSe0.75Te0.25

Cited by 23 publications

References 11 publications

Unexpected Ge–Ge Contacts in the Two‐Dimensional Ge₄Se₃Te Phase and Analysis of Their Chemical Cause with the Density of Energy (DOE) Function

Unexpected Ge–Ge Contacts in the Two‐Dimensional Ge₄Se₃Te Phase and Analysis of Their Chemical Cause with the Density of Energy (DOE) Function

Magnetically Induced Spin-Reversal Transitions in Impurity Hop Conduction inn-Type Germanium

Physical vapor transport and crystal growth of GeSe_xTe_1−x solid solutions

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The system Ge-Se-Te and the preparation and properties of the new non-stoichiometric compound GeSe0.75Te0.25

Cited by 23 publications

References 11 publications

Unexpected Ge–Ge Contacts in the Two‐Dimensional Ge4Se3Te Phase and Analysis of Their Chemical Cause with the Density of Energy (DOE) Function

Unexpected Ge–Ge Contacts in the Two‐Dimensional Ge4Se3Te Phase and Analysis of Their Chemical Cause with the Density of Energy (DOE) Function

Magnetically Induced Spin-Reversal Transitions in Impurity Hop Conduction inn-Type Germanium

Physical vapor transport and crystal growth of GeSexTe1−x solid solutions

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Unexpected Ge–Ge Contacts in the Two‐Dimensional Ge₄Se₃Te Phase and Analysis of Their Chemical Cause with the Density of Energy (DOE) Function

Unexpected Ge–Ge Contacts in the Two‐Dimensional Ge₄Se₃Te Phase and Analysis of Their Chemical Cause with the Density of Energy (DOE) Function

Physical vapor transport and crystal growth of GeSe_xTe_1−x solid solutions