Orientation in Ag2Se polymorphic films produced by the reaction of silver films with selenium

Saitō, Yoshio; Sato, Masanori; Shiojiri, Makoto

doi:10.1016/0040-6090(81)90314-x

Cited by 42 publications

(36 citation statements)

References 14 publications

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“…In some regions, the pseudo-orthorhombic crystals with slight deviations from the orthorhombic lattice are also observed, as reported by De Ridder & Amelinckx (1973) and Saito et al (1981), although the deviations are rather small compared with the values reported.…”

Section: Resultssupporting

confidence: 76%

“…The observed topotactic relations are, as seen from Fig. 5(c It is quite natural for the values to be different from those for Ag2S (Frueh, 1958) were mistaken for those for Ag2Se in the literature (De Ridder & Amelinckx, 1973;Saito et al, 1981). Fig.…”

Section: B Films With Excess Selenium; Ag2_~sementioning

confidence: 75%

“…(a = 5.65/~,) (Efendiev, Nuriev & Safizade, 1969;Constantinescu, 1976a,b), tetragonal (a = 7.06, c = 4.98 A) (Boettcher, Haase & Treupel, 1955;Junod, 1959), orthorhombic (a = 7.05, b = 7.82, c = 4.32,~) (Zorll, 1955;Conn& Taylor, 1960;Ching-Liang & Pinsker, 1962;Sharma, 1969), monoclinic [a = 6.91, b = 7.87, c = 4.23 ,~, o~ = 99 ° 35', although the lattice parameters have been wrongly cited from the values for Ag2S (Frueh, 1958)] (De Ridder & Amelinckx, 1973;Saito, Sato & Shiojiri, 1981) and sometimes triclinic (pseudo-orthorhombic, a = 7.0, b = 7.8, c = 4.3/~,, c~ = 92, fl = 91, 3, = 92 ° ) (De Ridder & Amelinckx, 1973). Saito et al (1981) have claimed, by using films produced by the reaction of vacuum-deposited silver films with amorphous selenium films, the existence of tetragonal, orthorhombic and triclinic modifications as low-temperature phases and monoclinic and f.c.c. modifications as metastable phases and also suggested that the orthorhombic modification is the stoichiometric Ag2Se compound while the tetragonal and triclinic modifications are non-stoichiometric compounds containing excess silver and excess selenium, respectively.…”

Section: Introductionmentioning

confidence: 99%

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High-resolution electron-microscopic studies of the polymorphs in Ag_2±δSe films

Okabe¹,

Ura²

1994

J Appl Cryst

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The polymorphs that appear in the low-temperature phase of silver selenide have been studied by highresolution electron microscopy. The specimen films are intentionally prepared with excess silver or selenium over stoichiometric composition by flash evaporation, asdepositing carbon films on both sides of the specimen films to protect them from selenium sublimation and to maintain the composition throughout the heat treatment. It is shown that four different types of low-temperature phase exist: tetragonal (a = 6.98, c = 4.96A) for a metastable phase only formed with a small grain size of less than 50 nm; face-centred cubic (a = 10.9 ~) for a non-stoichiometric phase with excess silver; monoclinic (a = 7.05, b = 8.17, c = 4.34~, o~ = 101.0 °) for a non-stoichiometric phase with excess selenium; and orthorhombic (a = 7.05, b = 7.82, c = 4.34A) for the stoichiometric stable phase. The topotactic relations between the orthorhombic and monoclinic types are found to be fully coherent, having the same a and c lattice parameters.

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Section: Resultssupporting

confidence: 76%

Section: B Films With Excess Selenium; Ag2_~sementioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

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High-resolution electron-microscopic studies of the polymorphs in Ag_2±δSe films

Okabe¹,

Ura²

1994

J Appl Cryst

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“…[5][6][7][8] Furthermore, entirely new crystal phases can arise on the nanoscale that have no known counterparts in bulk. [9][10][11][12][13] Because the physical properties of a material are linked to its crystalline structure, the ability to isolate new or difficult-to-access metastable structures on the nanoscale holds promise for the discovery of novel functional materials with properties different from, and possibly superior to, the properties of more thermodynamically stable materials. [14][15][16][17][18] To synthetically target such materials, it is important to consider that a metastable state is only isolable if, under some set of conditions, that state represents a thermodynamic minimum.…”

mentioning

confidence: 99%

Ligand-Mediated Phase Control in Colloidal AgInSe₂ Nanocrystals

2020

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Synthetic studies of colloidal nanoparticles that crystallize in metastable structures represent an emerging area of interest in the development of novel functional materials, as metastable nanomaterials may exhibit unique properties when compared to their counterparts that crystallize in thermodynamically preferred structures. Herein, we demonstrate how phase control of colloidal AgInSe2 nanocrystals can be achieved by performing reactions in the presence, or absence, of 1-dodecanethiol. The thiol plays a crucial role in formation of metastable AgInSe2 nanocrystals, as it mediates an in-situ topotactic cation exchange from an orthorhombic Ag2Se intermediate to a metastable orthorhombic phase of AgInSe2. We provide a detailed mechanistic description of this cation exchange process to structurally elucidate how the orthorhombic phase of AgInSe2 forms. Density functional theory calculations suggest that the metastable orthorhombic phase of AgInSe2 is metastable by a small margin, at 10 meV/atom above the thermodynamic ground state. In the absence of 1-dodecanethiol, a mixture of Ag2Se nanocrystal intermediates form that convert through kinetically slow, non-topotactic exchange processes to yield the thermodynamically preferred chalcopyrite structure of AgInSe2. Finally, we offer new insight into the prediction of novel metastable multinary nanocrystal phases that do not exist on bulk phase diagrams.

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“…The growth of silver selenide films through the reactiondiffusion of the elemental films has been studied for long time [15,34]. The films always exhibited a tendency to dewet the substrate and agglomerate, although an elaborative and quantitative study to establish the agglomeration has not been carried out.…”

Section: Scanning Electron Microscopymentioning

confidence: 99%

Thermal stability of silver selenide thin films on silicon formed from the solid state reaction of Ag and Se films

Mohanty

Kasiviswanathan

2006

Thin Solid Films

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Orientation in Ag2Se polymorphic films produced by the reaction of silver films with selenium

Cited by 42 publications

References 14 publications

High-resolution electron-microscopic studies of the polymorphs in Ag_2±δSe films

High-resolution electron-microscopic studies of the polymorphs in Ag_2±δSe films

Ligand-Mediated Phase Control in Colloidal AgInSe₂ Nanocrystals

Thermal stability of silver selenide thin films on silicon formed from the solid state reaction of Ag and Se films

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Orientation in Ag2Se polymorphic films produced by the reaction of silver films with selenium

Cited by 42 publications

References 14 publications

High-resolution electron-microscopic studies of the polymorphs in Ag2±δSe films

High-resolution electron-microscopic studies of the polymorphs in Ag2±δSe films

Ligand-Mediated Phase Control in Colloidal AgInSe2 Nanocrystals

Thermal stability of silver selenide thin films on silicon formed from the solid state reaction of Ag and Se films

Contact Info

Product

Resources

About

High-resolution electron-microscopic studies of the polymorphs in Ag_2±δSe films

High-resolution electron-microscopic studies of the polymorphs in Ag_2±δSe films

Ligand-Mediated Phase Control in Colloidal AgInSe₂ Nanocrystals