Sb Atoms Research Articles

Simulation Calculation and Analysis of Electronic Structure and Electrical Properties of Metal‐Doped SnO2

SnO2 is an almost insulated semiconductor material, which increases the contact resistance of the AgSnO2 electrical contact material. Therefore, by improving the electrical performance of SnO2, the electrical properties of the AgSnO2 can be optimized. The first principle method based on density functional theory is used to calculate the electronic structure, formation energy, band structure, density of states, and differential charge density of SnO2 doped with the metals Ti, Sr, Ge, Sb, and Ga. The results show that metal‐doped SnO2 materials are still direct bandgap semiconductor materials, and the effect of the electronic states of the metallic elements enhances the localization of the energy band, decreases the bandgap, increases the carrier concentration at the Fermi level, and enhances the electrical performance of the materials, and the bandgap of Ga‐doped SnO2 is the smallest, 0.041 eV. And the charge transfer between Sb, Sr, Ga, Ti, and Ge metal atoms and O atoms increases, especially between Ga atom and O atom; that is, the electrical performance of Ga doping is better.

Effect of Ti additions on structure and phase stability of Sb2Te3 thin films by experimental and theoretical methods

Influence of Ti additions in Sb2Te3 thin films on structure and phase stability was studied by experiments together with theoretical calculations. The incorporation of Ti atoms in the Sb2Te3 thin films caused formation of finer grains. By X-ray photoelectron spectroscopy and ab initio calculation, both the Sb and Te atoms are likely to be replaced by the Ti atoms to form Ti–Sb and Ti–Te covalent bonds. It suggests that the Ti atoms locate in Te1 position and interstice of the lattice.

Exploring the subsurface atomic structure of the epitaxially grown phase-change material Ge2Sb2Te5

Scanning tunneling microscopy (STM) and spectroscopy (STS) in combination with density functional theory (DFT) calculations are employed to study the surface and subsurface properties of the metastable phase of the phase change material Ge$_{2}$Sb$_{2}$Te$_{5}$ as grown by molecular beam epitaxy. The (111) surface is covered by an intact Te layer, which nevertheless allows to detect the more disordered subsurface layer made of Ge and Sb atoms. Centrally, we find that the subsurface layer is significantly more ordered than expected for metastable Ge$_{2}$Sb$_{2}$Te$_{5}$. Firstly, we show that vacancies are nearly absent within the subsurface layer. Secondly, the potential fluctuation, tracked by the spatial variation of the valence band onset, is significantly less than expected for a random distribution of atoms and vacancies in the subsurface layer. The strength of the fluctuation is compatible with the potential distribution of charged acceptors without being influenced by other types of defects. Thirdly, DFT calculations predict a partially tetrahedral Ge bonding within a disordered subsurface layer, exhibiting a clear fingerprint in the local density of states as a peak close to the conduction band onset. This peak is absent in the STS data implying the absence of tetrahedral Ge, which is likely due to the missing vacancies required for structural relaxation around the shorter tetrahedral Ge bonds. Finally, isolated defect configurations with a low density of $~10^{-4}$/nm$^2$ are identified by comparison of STM and DFT data, which corroborates the significantly improved order in the epitaxial films driven by the build-up of vacancy layers.

Lightly doped n-type tensile-strained single-crystalline GeSn-on-insulator structures formed by lateral liquid-phase crystallization

A tensile-strained single-crystalline n-type GeSn-on-insulator structure was demonstrated by lateral liquid-phase crystallization of an Sb-doped GeSn layer, and the diffusion and activation behaviors of Sb atoms in a liquid-phase-grown GeSn wire were investigated. A photoluminescence-based study revealed that a substantial amount of Sb was swept out during the liquid-phase growth of the GeSn wire. A thin-film transistor based on an Sb-doped GeSn wire on a quartz substrate exhibited n-channel accumulation-mode operation, and the temperature dependence of field-effect mobility revealed that the single-crystalline GeSn wire is a lightly doped n-type (∼1017 cm−3). The combination of Sb-doped n-type and undoped p-type GeSn wires would be an ideal platform for GeSn-based optoelectronic integration.

The ternary phases Cu1.5−x Li1+x Sb and Cu4+x Li1−x Sb2, and their structural relations

Abstract In the course of investigations on the phase relations in the Cu–Li–Sb system, two yet unknown ternary phases, namely Cu1.5−x Li1+x Sb and Cu4+x Li1−x Sb2 were synthesized and characterized by powder and single crystal X-ray diffraction experiments. Both title compounds show hexagonal symmetry (a=4.3593(10)/4.2512(9), c=14.445(5)/22.336(7) Å, space groups P63 mc and P6̅m2). Strong structural relations are evident among each other and to the compound Cu2−x Li1−x Sb (a=4.3415(8), c=7.448(2) Å, space group P63/mmc). The symmetry change of the different structures goes along with a multiplication of c whereas the lattice parameter a is roughly maintained. The Sb atoms are more or less ordered. Cu and Li atoms are extensively disordered, vacancies are common. The substructure formed by the Sb atoms is densely packed, the stacking sequence of the compounds Cu1.5−x Li1+x Sb, Cu4+x Li1−x Sb2 and Cu2−x Li1−x Sb is ABAC, ABCACB, and AB, respectively.

Radioactive Equilibrium of 119mTe/119Sb Isotopes and Mössbauer Spectra of Impurity 119mSn Atoms in Crystalline and Vitreous Chalcogenide Semiconductors

Information on the valence and coordination states of the daughter 119mSn atoms formed from the parent 119Sb and 119mTe atoms at the cation and anion sites of crystalline lead chalcogenides (PbS, PbTe) and vitreous arsenic chalcogenides (As2S3, As2Te3) is obtained by the method of emission Mossbauer spectroscopy with the parent 119mTe isotope being in a state of mobile radioactive equilibrium with the daughter 119Sb isotope. It is shown that the ratio of different valence and coordination states of tin atoms in crystals and glasses depends on the time of the preparation of Mossbauer sources. The displacement of a part of the daughter 119Sb atoms from positions of parent 119mTe atoms as a result of the decay of the latter is demonstrated.

Tris(3-fluorophenyl)antimony dicarboxylates (3-FC6H4)3Sb[OC(O)R]2 (R = CH2Cl, Ph, CH2C6H4NO2-4, C10H15): Synthesis and structure

Tris(3-fluorophenyl)antimony dicarboxylates (3-FC6H4)3Sb[OC(O)R]2, R = CH2Cl (I), Ph (II), CH2C6H4NO2-4 (III), C10H15 (IV)) have been synthesized with a high yield by the reaction between tris(3-fluorophenyl)antimony and carboxylic acids in ether in the presence of tert-butyl hydroperoxide. The Sb atoms in complexes I–IV have a distorted trigonal bipyramidal coordination with carboxylate ligands in axial positions. The OSbO angles are 176.61(11)° (I), 177.8(2)°, 175.9(3)° (II), 173.25(16)° (III), and 177.84(14)° (IV). The Sb–O and Sb–Ceqv bond lengths are 2.111(3), 2.131(3) and 2.102(5)–2.117(4) A (I); 2.101(1)–2.547(6) and 2.103(8)–2.132(7) A (II); 2.035(7), 2.144(6) and 2.116(9)–2.130(10) A (III); 2.131(5), 2.156(4) and 2.103(2)–2.153(5) A (IV). The carboxylate ligands show anisobidentate properties, and the Sb⋯О=С distances are 2.804(4), 2.923(4) A (I), 2.541(8)–2.747(9) A (II), 2.967(9), 3.007(9) A (III), and 2.561(9), 2.617(9) A (IV). The structural organization in crystals is based on weak intermolecular hydrogen bonds H⋯F (2.48–2.64 A) and H⋯O(=C) (2.55–2.71 A).

Study of the characteristics, properties and characterization of new SiO2/TiO2/Sb2O5 ternary oxide obtained by the sol–gel process

SiO2/TiO2/Sb2O5 ternary oxide was prepared by the sol–gel method in two different proportions, and were characterized by X-ray fluorescence (XRF), analysis of the specific surface area by BET and the average pore size and pore volume by BJH method, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS) analyses, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and other spectroscopic technics (FT-Raman, FT-IR, UV–Vis–NIR and DRS). The ternary oxides showed high surface area 758 and 529 m2 g−1 for SiTiSb-A and SiTiSb-B, respectively. The binding energy values for the Sb 3d and Ti 2p levels show the insertion of Sb and Ti atoms in the silica matrix, confirming the high dispersion of the metals presented in SEM, both in the bulk and on the surface. The thermogravimetric analysis (TGA) showed weight loss of 23% for both ternary oxides. The crystallographic data showed an increase of the crystalline order with the increase of the temperature of the thermal treatment. The anatase phase as well as a small content of the rutile phase of TiO2 were identified by FT-Raman. The Raman spectrum corroborated with the DTA and XRD of the SiTiSb-B which showed a slight decrease in the degree of crystallinity. Optical band gap values are dependent on the content of oxides. The pyridine adsorption studies showed the presence of Lewis and Bronsted acid sites on the SiTiSb ternary oxide surface, where the SiTiSb-B presented more acid sites on the surface.

Synthesis, Structure, Te Alloying, and Physical Properties of CuSbS2.

Materials with very low thermal conductivities continue to be of interest for a variety of applications. We synthesized CuSbS2 employing a mechanical alloying technique in order to investigate its physical properties. The trigonal pyramid arrangement of the S atoms around the Sb atoms allows for lone-pair electron formation that results in very low thermal conductivity. In addition to thermal properties, the structural, electrical, and optical properties, as well as compositional stability measurements, are also discussed. CuSbS1.8Te0.2 was similarly synthesized and characterized in order to compare its structural and transport properties with that of CuSbS2, in addition to investigating the effect of Te alloying on these properties.

A quantum chemical analysis of Zn and Sb doping and co-doping in SnO2

This work presents a quantum chemical study of Zn and Sb doping and co-doping in SnO2 carried out by a DFT+U method. The analysis has been developed by introducing three different modifications in the otherwise pure SnO2 system. In the first place, an oxygen vacancy was introduced within the crystal. Following, such a system was doped (separately) by Zn or Sb impurities. Finally, the best energetic positions for both Zn and Sb atoms were simultaneously introduced within the lattice. Results of the simulations show that the confined charge that appeared due to the introduction of the oxygen vacancy interacts with the dopants atoms, being this interaction mostly responsible of the observed effects, i.e., EG shrinkage, F-centers formations, and magnetic momentum rise.

Tetra- and triarylantimony pentafluoroand pentachlorophenoxides: Synthesis and structure

2,3,4,5,6-Pentafluorophenoxytetraphenylantimony (I), 2,3,4,5,6-pentachlorophenoxytetraphenylantimony (II), 2,3,4,5,6-pentafluorophenoxytetra-p-tolylantimony (III), and 2,3,4,5,6-pentachlorophenoxytetra-p-tolylantimony (IV) were synthesized by the reaction of pentaarylantimony (Ar = Ph, p-Tol) with pentafluoro- and pentachlorophenol in toluene. Compounds I–IV were also synthesized with yields of up to 95% from pentaarylantimony and triarylantimony diaroxides. Triarylantimony diaroxides Ph3Sb(OC6F5)2 (V), Ph3Sb(OC6Cl5)2 (VI), p-Tol3Sb(OC6F5)2 (VII), p-Tol3Sb(OC6Cl5)2 (VIII) were synthesized from triarylantimony, tert-butylhydroperoxide, and phenol in ether. The Sb atoms in compounds I–VIII had a distorted trigonal bipyramidal coordination with electronegative ligands in axial positions.

Mott theory predicted thermoelectric properties based on electronic structure of Bi and Sb atoms substituted PbTe material

In this work, thermoelectric properties of Bi and Sb atoms substituted PbTe material were predicted by Mott theory through electronic structure calculation. This calculation has been carried by the first-principles DV-Xα molecular orbital method based on Hartree-Fock-Slater approximation. The Pb14Te13, Pb13SbTe13 and Pb13BiTe13 small clusters with a cubic rocksalt structure (Fm-3m; 225) were designed to be performed PbTe, Pb0.75Sb0.25Te and Pb0.75Bi0.25Te materials, respectively. The electronic structure showed that the high symmetry crystal structure, spin energy levels, partial spin density of states and electron charge density. The energy gap and Fermi level have been obtained from energy levels and density of state to be evaluated of electrical conductivity and Seebeck coefficient within Mott's theory predication.

Tris(para-tolyl)- and tris(4-fluorophenyl)antimony diaroxides: syntheses and structures

Bis(4-bromophenoxy)tris(para-tolyl)antimony (I), bis(4-nitrophenoxy)tris(para-tolyl)antimony (II), bis(4-nitrophenoxy)tris(4-fluorophenyl)antimony (III), bis(2,3,4,5,6-pentafluorophenoxy)tris(4-fluorophenyl) antimony (IV), and bis(2,3,4,5,6-pentachlorophenoxy)tris(4-fluorophenyl)antimony (V) (CIF files CCDC 1470829 (I), 1474589 (II), 1062337 (III), 1470476 (IV), and 1472954 (V)) are synthesized in high yields by the reactions of tris(para-tolyl)- and tris(4-fluorophenyl)antimony with 4-bromo-, 4-nitro-, 2,3,4,5,6-pentafluoro-, and 2,3,4,5,6-pentachlorophenol, respectively, in diethyl ether in the presence of tert-butyl hydroperoxide. The Sb atoms in compounds I–V have a distorted trigonal bipyramidal coordination with the aroxy groups in the axial positions (angles OSbO 174.08(11)°–179.4(5)°). The average Sb–C bond lengths in compounds I–V are similar and independent of the nature of the para-substituent in the aryl rings. The Sb–O distances are close to the sum of covalent radii of Sb and O atoms. Hydrogen bonds H···F are involved in the formation of the crystal structures of compounds III–V.

Formation of low-dimensional structures in the InSb/AlAs heterosystem

Low-dimensional quantum-well and nanoisland heterostructures formed in the InSb/AlAs system by molecular-beam epitaxy are studied by transmission electron microscopy and steady-state photoluminescence spectroscopy. The structures are grown under conditions of alternate In and Sb deposition (the socalled atomic-layer epitaxy mode) and the simultaneous deposition of materials (the traditional molecularbeam epitaxy mode). In both modes of growth, at a nominal amount of the deposited material in a single layer, large-sized (200 nm–1 μm) imperfect islands arranged on the In x Al1 – x Sb y As1–y quantum-well layer are formed. In the heterostructures grown under conditions of atomic layer epitaxy, the islands are surrounded by ring-shaped arrays of much smaller (~10 nm), coherently strained islands consisting of the In x Al1 – x Sb y As1 – y alloy as well. The composition of the alloy is defined by the intermixing of Group-V materials in the stage of InSb deposition and by the intermixing of materials because of the segregation of In and Sb atoms during overgrowth of the InSb layer by an AlAs layer.

Donor and acceptor energy levels in impurity Sb-, In-, Ag- and Cu-doped semiconducting BaSi2 thin films for device applications

In this article donor and acceptor energy levels due to the impurity Sb-, In-, Ag- and Cu-doped BaSi2 films grown in the ultra-high vacuum, UHV molecular beam epitaxy (MBE) were investigated. The temperature dependence of electron or hole concentrations indicated that the acceptor energy levels in impurity, In-, and Ag-doped BaSi2 are 86 meV, and 126 meV, respectively, and the donor energy levels in impurity Cu-, and Sb-doped BaSi2 are 35 meV, and 47 meV respectively. Two shallow donor energy levels of 47 meV and 35 meV respectively due to Sb and Cu impurity atoms in n-type BaSi2 were successfully identified for the device applications including photovoltaic.

Low-temperature (330 °C) crystallization and dopant activation of Ge thin films via AgSb-induced layer exchange: Operation of an n-channel polycrystalline Ge thin-film transistor

Ge thin films have been prepared by layer-exchange metal-induced crystallization using AgSb alloy as a catalyst. Not only the crystallization of Ge, but also the incorporation of Sb atoms into the crystalline Ge layer and their activation have been realized during the process at a temperature as low as 330 °C. Thin-film transistors have been fabricated using the Ge thin films as channel layers and the operation of an n-channel transistor with an on/off ratio of over 300 has been demonstrated.

Robustness of topological states with respect to lattice instability in the nonsymmorphic topological insulator KHgSb

We report a polarized Raman scattering study of non-symmorphic topological insulator KHgSb with hourglass-like electronic dispersion. Supported by theoretical calculations, we show that the lattice of the previously assigned space group $P6_3/mmc$ (No. 194) is unstable in KHgSb. While we observe one of two calculated Raman active E$_{2g}$ phonons of space group $P6_3/mmc$ at room temperature, an additional A$_{1g}$ peak appears at 99.5 ~cm$^{-1}$ upon cooling below $T^*$ = 150 K, which suggests a lattice distortion. Several weak peaks associated with two-phonon excitations emerge with this lattice instability. We also show that the sample is very sensitive to high temperature and high laser power, conditions under which it quickly decomposes, leading to the formation of Sb. Our first-principles calculations indicate that space group $P6_3mc$ (No. 186), corresponding to a vertical displacement of the Sb atoms with respect to the Hg atoms that breaks the inversion symmetry, is lower in energy than the presumed $P6_3/mmc$ structure and preserves the glide plane symmetry necessary to the formation of hourglass fermions.

Tetra-para-tolylantimony derivatives (4-MeC6H4)4SbX, X = OC(O)C6H4(NO2-2), OC(O)C≡CPh, ON=CHC6H4(NMe2-4): Synthesis and structure

Tetra-para-tolylantimony derivatives (4-MeC6H4)4SbX, X = OC(O)C6H4(NO2-2) (I), OC(O)C≡CPh (II), ON=CHC6H4(NMe2-4) (III)) have been synthesized by the reaction between penta-para-tolylantimony and 2-nitrobenzoic and phenylpropiolic acids and 4-dimethylaminobenzaldoxime in benzene. Using X-ray diffraction, it has been established that the Sb atoms in molecules of complexes I–III are in distorted trigonal bipyramidal coordination to X groups in axial positions. The Sb–O bond lengths are 2.2797(16) (I), 2.2925(17) (II), and 2.1357(17) A (III). The CSbO axial angles are 178.28(7)° (I), 178.57(9)° (II), 176.09(8)° (III).

The ternary phases CuLi2−x Sb, Cu2−x Li1+x Sb, and Cu2−x Li1−x Sb and their structural relations to binary alloys in the systems Cu−Sb and Li−Sb

Abstract In the course of studies on the phase relations in the system Cu−Li−Sb at 400 °C the ternary compounds CuLi2−x Sb, Cu2−x Li1+x Sb and Cu2−x Li1−x Sb were synthesized by melting processes followed by long-time annealing procedures. They were chemically as well as structurally characterized. Powder and single-crystal X-ray diffraction investigations proved that CuLi2−x Sb crystallizes cubic (space group F4̅3m, a=6.248(2) Å) and Cu2−x Li1−x Sb hexagonal (space group P63/mmc, a=4.3415(8) Å, c=7.448(2) Å). For Cu2−x Li1+x Sb the average structure is cubic (space group Fm3̅m, a=6.169(2) Å). However, it was not possible to unravel split reflections seen in the single-crystal diffraction images. Powder X-ray diffraction patterns gave a hint for tetragonal symmetry (a=4.3832(1) Å, c=6.0512(2) Å). It is assumed, that Cu2−x Li1+x Sb is formed from Cu-rich CuLi2−x Sb in a second order transition reaction during cooling; single domains could not be separated. The three title compounds show close structural relations among each other as well as to the binary compounds Li3Sb (P63/mmc and Fm3̅m modifications), β-Cu3Sb (Fm3̅m), η-Cu2Sb (P4/nmm) and δ-Cu4Sb (P63/mmc). In all cases, the Sb atoms are in a fully ordered ccp or hcp arrangement. In between are the Cu and Li atoms. They exhibit an extensive disorder due to both, mixed and partial occupations making the alloy system Cu–Li–Sb a candidate for electrode materials to be used in Li-ion batteries.

Donor and acceptor levels in impurity-doped semiconducting BaSi2 thin films for solar-cell application

Identification of donor and acceptor energy levels in BaSi2 due to the suitable impurity injection of different types is very essential for the design and development of heterojunction or homojunction solar cells. In this article, donor and acceptor energy levels due to the impurity Sb-, In-, Ga-, Cu-, Al-, Ag-, P-, and B-doped BaSi2 films grown by molecular beam epitaxy (MBE) were investigated. It was found that impurity Sb-, Ga-, Cu-, and P-doped BaSi2 exhibited n-type conductivity, while impurity In- Al-, Ag-, and B-doped BaSi2 exhibited p-type conductivity, using the Van der Pauw method at room temperature (RT). The temperature dependence of electron or hole concentrations indicated that the acceptor energy levels in impurity B-, In-, Ag-, and Al-doped BaSi2 are 23, 86, 126, and 140 meV, respectively, and the donor energy levels in impurity Cu-, Sb-, P-, and Ga-doped BaSi2 are 35, 47, 80, and 120 meV, respectively. The shallow acceptor level of 23 meV in p-type BaSi2 due to B impurity atoms and two novel donor levels of 47 and 35 meV, respectively, due to Sb and Cu impurity atoms in n-type BaSi2 were successfully identified for photovoltaic applications.