Polymorphism in some iv‐vi compounds induced by high pressure and thin‐film epitaxial growth
TL;DR: The NaCl structures PbS, PbSe, pbTe and SnTe have been found to transform to a Pnma orthorhombic (distorted NaCl) structure under high pressures as discussed by the authors.
Abstract: The NaCl structures PbS, PbSe, PbTe and SnTe have been found to transform to a Pnma orthorhombic (distorted NaCl) structure under high pressures. Epitaxial growth on rock salt of thin films of normally orthorhombic (Pnma) SnS, SnSe and PbSnS2 induces NaCl structures. There exists a close correlation between the lattice constants of the corresponding NaCl and the orthorhombic polymorphic structures of the Pb and Sn compounds.
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TL;DR: In this article, the inherent relationship between the structural characteristics and the thermoelectric performance of tin selenide (SnSe) is discussed, including the thermodynamics, crystal structures, and electronic structures.
389 citations
TL;DR: This review looks beyond MAPI to other ns2 solar absorbers, with the aim of identifying those materials likely to achieve high efficiencies, and discusses the ideal properties essential to produce highly efficient solar cells.
358 citations
TL;DR: Recent efforts made towards achieving synthetic control over nanocrystal size and morphology of the non-lead containing IV-VI monochalcogenides and their application toward photovoltaic devices are highlighted.
Abstract: The incorporation of colloidal semiconductor nanocrystals into the photoabsorbant material of photovoltaic devices may reduce the production costs of solar cells since nanocrystals can be readily synthesized on a large scale and are solution processable. While the lead chalcogenide IV–VI nanocrystals have been widely studied in a variety of photovoltaic devices, concerns over the toxicity of lead have motivated the exploration of less toxic materials. This has led to the exploration of tin and germanium monochalcogenide IV–VI semiconductors, both of which are made up of earth abundant elements and possess properties similar to the lead chalcogenides. This feature article highlights recent efforts made towards achieving synthetic control over nanocrystal size and morphology of the non-lead containing IV–VI monochalcogenides (i.e., SnS, SnSe, SnTe, GeS and GeSe) and their application toward photovoltaic devices.
258 citations
TL;DR: In this paper, core-level and valence-band spectra have been obtained by means of x-ray photoemission spectroscopy for the group IV, V, and VI elements Ge, Sn, Pb, As, Sb, Bi, S, Se, and PbTe and the results, taken under ultrahigh-vacuum conditions with unmonochromatized x rays, are presented and discussed in terms of the bonding in materials with an average valence of 5.
Abstract: Core-level and valence-band spectra have been obtained by means of x-ray photoemission spectroscopy for the group IV, V, and VI elements Ge, Sn, Pb, As, Sb, Bi, S, Se, and Te and the group IV-VI compounds GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbS, PbSe, and PbTe. These results, taken under ultrahigh-vacuum conditions with unmonochromatized x rays, are presented and discussed in terms of the bonding in materials with an average valence of 5. The effects of relaxation on the chemical shifts are found to be relatively small. The chemical shifts are found to vary in a manner similar to that expected from the magnitude of the elemental electronegativities except for the ordering of the shifts of GeS and GeSe. Relative charge transfers are calculated from the chemical shifts and are found to be in general agreement with ionicities calculated using the Phillips-Van Vechten theory although there is some disagreement as to their magnitudes. A consideration of the structures of the compounds relative to the charge transfers demonstrates the importance of metallic as well as covalent and ionic bonding in determining the most stable structure. The value of critical ionicity carried over from the average-valence-4 materials does not apply to the average-valence-5 materials and this concept does not appear useful in understanding their bonding because of the increased importance of nondirectional metallic bonding.
247 citations
TL;DR: In this paper, first-principles calculations are employed to better understand this novel geometry and its place within the tin sulfide multiphasic system, and the enthalpies of formation for the known phases of SnS, SnS2, and Sn2S3 are reported.
Abstract: The various phases of tin sulfide have been studied as semiconductors since the 1960s and are now being investigated as potential earth-abundant photovoltaic and photocatalytic materials. Of particular note is the recent isolation of zincblende SnS in particles and thin-films. Herein, first-principles calculations are employed to better understand this novel geometry and its place within the tin sulfide multiphasic system. We report the enthalpies of formation for the known phases of SnS, SnS2, and Sn2S3, with good agreement between theory and experiment for the ground-state structures of each. While theoretical X-ray diffraction patterns do agree with the assignment of the zincblende phase demonstrated in the literature, the structure is not stable close to the lattice parameters observed experimentally, exhibiting an unfeasibly large pressure and a formation enthalpy much higher than any other phase. Ab initio molecular dynamics simulations reveal spontaneous degradation to an amorphous phase much lower...
202 citations
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TL;DR: In this article, the theory of a one-dimensional dislocation model is developed, and critical conditions for spontaneous generation (or escape) of dislocations are determined, and also the activation energies for such processes below the critical limits.
Abstract: The theory of a one-dimensional dislocation model is developed. Besides acting as a pointer to developments of general dislocation theory, it has a variety of direct physical applications, particularly to monolayers on a crystalline substrate and to conditions in the edge row of a terrace of molecules in a growing crystal. Allowance is made in the theory for a difference in natural lattice-spacing between the surface layer or row and the substrate. The form and energy of single dislocations and of regular sequences of dislocations are calculated. Critical conditions for spontaneous generation (or escape) of dislocations are determined, and likewise the activation energies for such processes below the critical limits. Various physical applications of the model are discussed, and the physical parameters are evaluated with the aid of the Lennard-Jones force law for the above-mentioned principal applications.
1,105 citations
TL;DR: At 18 kilobars, tin telluride transforms from a sodium chloride-type structure to an orthorhombic crystal structure (space group Pnma), accompanied by a 360-percent increase in electrical resistivity.
Abstract: At 18 kilobars, tin telluride transforms from a sodium chloride-type structure to an orthorhombic crystal structure (space group Pnma). This structural change is accompanied by a 360-percent increase in electrical resistivity.
46 citations
TL;DR: In this article, electron diffraction at various substrate temperatures and at different values of laterally applied electric field has been used to investigate changes in the structure of vacuum-evaporated CdS films.
38 citations
TL;DR: The melting curve of tintelluride (Sn0.496Te0.504) was determined by differential thermal analysis at pressures between 5 and 40 kilobars and found the liquid and two solid polymorphs coexist.
Abstract: The melting curve of tintelluride (Sn0.496Te0.504 was determined by differential thermal analysis at pressures between 5 and 40 kilobars. Near 844°±4°C and 12.0±1.0 kb, the liquid and two solid polymorphscoexist.
6 citations