Effect Of Sb Doping Research Articles

Effect of Sb doping on the opto-electronic properties of SnO2 nanowires

Antimony (Sb) doping of SnO2 nanowires (NWs) was investigated for its optical and electrical effects. The low-temperature photoluminescence spectra of SnO2 NWs varied significantly with increasing Sb content, where the temperature-dependence of the visible emission at ca. 400nm was distinctive with Sb-doping, indicating different defect states, such as neutral and positively charged oxygen vacancies. Field effect transistors (FETs) with low-level Sb-doped SnO2 NW channels exhibited higher mobility, charge concentration, and faster response and recovery to UV light than intrinsic SnO2 NW FETs.

Effect of Sb doping on the microstructure and optoelectrical properties of Sb-doped SnO2 films prepared by spin coating

Sb-doped SnO2 (ATO) films were successfully prepared by the spin-coating method starting from colloidal suspensions of ATO nanocrystalline particles. The structural, surface morphological, electrical and optical properties of the films were studied as a function of Sb-doping concentration ranging from 0 to 20% (Sb/(Sb + Sn)). The results indicated that all films were ATO polycrystalline with the typical tetragonal crystal structure of bulk SnO2. The monotonic decrease of the x-ray diffraction (XRD) peak intensity and the increase of XRD peak width with Sb-doping concentration indicated a finer crystal size distribution and a decrease in crystallization. The films had a porous and netlike microstructure with a more homogeneous and closely packed distribution of nanoclusters when the Sb-doping concentration was increased. The electrical resistivity decreased sharply from 1765 to 0.66 Ω cm when the Sb-doping concentration was increased from 0 to 15% and then decreased slightly to 0.52 Ω cm when the Sb-doping concentration was increased from 15 to 20%. The film transmittance decreased from 82 to 61% in the visible region. The calculated optical band gap energy first decreased from 4.01 to 3.61 eV and then slightly increased to 3.61 eV, reaching a minimum value at 15% Sb-doping concentration. The pore/grain contact scattering mechanism of an electron and a photon is presented to explain the novel optoelectrical properties of the films.

Thermoelectric Properties of Half-Heusler ZrNiSn1-xSbxSynthesized by Mechanical Alloying Process and Vacuum Hot Pressing

Half-heusler phase ZrNiSn is one of the potential thermoelectric materials for high temperature application. In an attempt to investigate the effect of Sb doping on thermoelectric properties, half-heusler phase () was synthesized by mechanical alloying of stoichiometric elemental powder compositions, and consolidated by vacuum hot pressing. Phase transformations during mechanical alloying and hot consolidation were investigated using XRD. Sb doped ZrNiSn was successfully produced in all doping ranges by vacuum hot pressing using as-milled powders without subsequent annealing. Thermoelectric properties as functions of temperature and Sb contents were evaluated for the hot pressed specimens. Sb doping up to x

Effect of Sb Doping on the Thermoelectric Properties of Mg2Si0.7Sn0.3 Solid Solutions

This study focuses on Sb-doped Mg2(Si,Sn) thermoelectric material. Samples were successfully fabricated using a hybrid synthesis method consisting of three different processes: induction melting, solid-state reaction, and a hot-press sintering technique. We found that the carrier concentration increased with Sb content, while the Seebeck coefficient exhibited a decreasing trend. Sb doping was shown to improve the power factor and thermoelectric figure of merit compared with the undoped material, yielding a peak figure of merit (ZT) of ~0.55 at 620 K, while leaving the band gap of Mg2Si0.7Sn0.3 almost unchanged.

Characteristics of undoped and Sb‐doped ZnO thin films prepared in different atmospheres by pulsed laser deposition

AbstractUndoped and 0.56 at.% Sb‐doped ZnO thin films were prepared by pulsed laser deposition (PLD) under vacuum and an oxygen pressure of 0.2 Pa with sintered ceramic as targets. The effects of Sb doping and deposition atmosphere on structure and optical–electrical properties of the films were studied by X‐ray diffraction (XRD), scanning probe microscopy (SPM), Hall Effect measurement, transmittance spectra, and photoluminescence (PL) spectra. The results showed that undoped and Sb‐doped films deposited under vacuum had better crystallinity, higher carrier concentration, lower bandgap (Eg), and single violet emission as compared with the films deposited in an oxygen pressure of 0.2 Pa. Compared with undoped ZnO film, Sb‐doped ZnO film had higher carrier concentration and almost uniform Eg in both atmospheres, and it exhibited obviously improved crystallinity and green emission under an oxygen pressure of 0.2 Pa. The results implied that the deposition atmosphere strongly affected the growth kinetics of the films and intrinsic defect in the films, and Sb doping seemed also to affect the growth kinetics of the films under certain conditions and introduced SbZn defects and possibly SbZn‐2VZn defects, thus the structure and optical–electrical properties of the films were modified by the deposition atmosphere and Sb doping.

Evolution of cobalt spin states and magnetic coupling along the SrCo1−xSbxO3−δ system: correlation with the crystal structure

The oxides of the SrCo(1-x)Sb(x)O(3-δ) perovskite family have been recently designed, characterized and described as cathode materials for solid-oxide fuel cells with competitive power performance in the temperature range 750-850 °C. They feature a number of interesting properties including a good electronic conductivity, low electrode polarization resistance and adequate thermal expansion; the crystal structure adopts a 3C corner-linked perovskite network with a considerable number of oxygen vacancies. This paper reports on the effects of Sb-doping on the crystal structure features, the Co oxidation state and magnetic properties related to the presence of spin-state transitions in the Co cations. A phase transition was observed from the tetragonal P4/mmm space group for x≤ 0.15 to the cubic Pm ̅3m space group in the x = 0.2 composition from neutron powder diffraction data. For the tetragonal phases the oxygen vacancies were found to be ordered and localized in the axial O2 and equatorial O3 atoms surrounding the Co2 positions. A noticeable distortion of CoO(6) octahedra is observed for x = 0.05 and 0.1, exhibiting a charge-ordering with a mixed oxidation state of Co(3+/4+) at Co1 sites and Co(3+) at Co2 positions: the Jahn-Teller Co(3+) in an intermediate-spin configuration is responsible for the octahedral distortion. Increasing Sb contents promotes a higher average oxidation state of cobalt, from a valence of 3.2+ for x = 0.05 to 3.4+ for x = 0.2, inducing a decrease of the oxygen vacancies and favouring a random distribution over a Pm ̅3m cubic symmetry. All the samples present an antiferromagnetic behaviour with a G-type (k = 0) magnetic structure. The increase of the Sb content induces the weakening of the crystal field (Δ(cf)) in the octahedral environment promoting the Co spin-transition from the intermediate-spin to the high-spin configuration, as evidenced by the decrease of the octahedral distortion, increment of the unit-cell volume and enhancement of the ordered magnetic moment.

Photocatalytic Properties of Tin Oxide and Antimony-Doped Tin Oxide Nanoparticles

For the first time it is shown that N-doped SnO2nanoparticles photocatalyze directly the polymerization of the C=C bonds of (meth)acrylates under visible light illumination. These radical polymerizations also occur when these particles are doped with Sb and when the surfaces of these particles are grafted with methacrylate (MPS) groups. During irradiation with visible or UV light the position and/or intensity of the plasmon band absorption of these nanoparticles are always changed, suggesting that the polymerization starts by the transfer of an electron from the conduction band of the particle to the (meth)acrylate C=C bond. By using illumination wavelengths with a very narrow band width we determined the influence of the incident wavelength of light, the Sb- and N-doping, and the methacrylate (MPS) surface grafting on the quantum efficiencies for the initiating radical formation (Φ) and on the polymer and particle network formation. The results are explained by describing the effects of Sb-doping, N-doping, and/or methacrylate surface grafting on the band gaps, energy level distributions, and surface group reactivities of these nanoparticles. N-doped (MPS grafted) SnO2(Sb ≥ 0%) nanoparticles are new attractive photocatalysts under visible as well as UV illumination.

Structural and superconducting properties of LaFeAs1−x Sb x O1−y F y

We report the antimony (Sb) doping effect in a prototype system of iron-based superconductors LaFeAsO1−y F y (y=0, 0.1, 0.15). X-ray powder diffraction indicates that the lattice parameters increase with Sb content within the doping limit. Rietveld structural refinements show that, with the partial substitution of Sb for As, the thickness of the Fe2As2 layers increases significantly, whereas that of the La2O2 layers shrinks simultaneously. So a negative chemical pressure is indeed “applied” to the superconducting-active Fe2As2 layers, in contrast to the effect of positive chemical pressure by the phosphorus doping. Electrical resistance and magnetic susceptibility measurements indicate that, while the Sb doping hardly influences the SDW anomaly in LaFeAsO, it recovers SDW order for the optimally-doped sample of y=0.1. In the meantime, the superconducting transition temperature can be raised up to 30 K in LaFeAs1−x Sb x O1−y F y with x=0.1 and y=0.15. The Sb doping effects are discussed in term of both J 1–J 2 model and Fermi Surface (FS) nesting scenario.

First-principles study of La and Sb-doping effects on electronic structure and optical properties of SrTiO3

The effects of La and Sb doping on the electronic structure and optical properties of SrTiO3 are investigated by first-principles calculation of the plane wave ultra-soft pseudo-potential based on density functional theory. The calculated results reveal that corner-shared TiO6 octahedra dominate the main electronic properties of SrTiO3, and its structural stability can be improved by La doping. The La3+ ion fully acts as an electron donor in Sr0.875La0.125TiO3 and the Fermi level shifts into the conduction bands (CBs) after La doping. As for SrSb0.125Ti0.875O3, there is a distortion near the bottom of the CBs for SrSb0.125Ti0.875O3 after Sb doping and an incipient localization of some of the doped electrons trapped in the Ti site, making it impossible to describe the evolution of the density of states (DOS) within the rigid band model. At the same time, the DOSs of the two electron-doped systems shift towards low energies and the optical band gaps are broadened by about 0.4 and 0.6 eV for Sr0.875La0.125TiO3 and SrSb0.125Ti0.875O3, respectively. Moreover, the transmittance of SrSb0.125Ti0.875O3 is as high as 95% in most of the visible region, which is higher than that of Sr0.875La0.125TiO3(85%). The wide band gap, the small transition probability and the weak absorption due to the low partial density of states (PDOS) of impurity in the Fermi level result in the significant optical transparency of SrSb0.125Ti0.875O3.

Effects of Sb-doping on the formation of (K, Na)(Nb, Sb)O3 solid solution under hydrothermal conditions

Abstract (K, Na)(Nb, Sb)O3 (KNNS) lead-free peizoceramic powders were successfully synthesized by hydrothermal treatment at 240 °C for 8 h using the KOH, NaOH, Nb2O5 and Sb2O3 as raw materials. Effects of Sb-doping on the crystal structure and morphology of the as-prepared powders were investigated by powder X-ray diffraction (XRD), Raman spectra (Raman), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The Sb element was successfully doped into the alkaline niobate perovskite structure to form crystalline (K0.7Na0.3)(Nb0.95Sb0.05)O3 lead-free piezoelectric ceramic powder, which has a hexagonal morphology due to the aggregation growth of small grains. Phase and morphology evolutions with the reaction time were also studied, and a possible formation mechanism was proposed.

Effect of antimony incorporation on structural properties of CuInS 2 crystals

CuInS 2 (CIS) single crystals doped with 1, 2, 3 and 4 atomic percent (at.%) of antimony (Sb) were grown by the horizontal Bridgman method. The effect of Sb doping on the structural properties of CIS crystal was studied by means of X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM) and PL measurements. X-ray diffraction data suggests that the doping of Sb in the CIS single crystals does not affect the tetragonal (chalcopyrite) crystal structure and exhibited a (1 1 2) preferred orientation. In addition, with increasing Sb concentration, the X-ray diffraction analysis show that Sb doped CIS crystals are more crystallized and the diffraction peaks of the CuInS 2 phase were more pronounced in particular the (1 1 2) plane. EDAX study revealed that Sb atoms can occupy the indium site and/or occupying the sulfur site to make an acceptor. PL spectra of undoped and Sb doped CIS crystals show two emission peaks at 1.52 and 1.62 eV, respectively which decreased with increasing atomic percent antimony. Sb doped CIS crystals show p-type conductivity.

From Kondo semimetal to spin-glass behaviour in doped CeNi1−δSn1+δ−x Sb x system

We investigate the properties of the off-stoichiometric CeNi1−δSn1+δ−x Sb x systems with δ ≈ 0.06 and 0 < x ≤ 0.22. Such a semimetallic CeNi1−δSn1+δ−x Sb x system is shown to transform into a Kondo semiconductor upon the substitution of about 2% of Sb for Sn. The effects of Sb doping on the low-temperature properties of CeNiSn were studied by means of electrical resistivity, magnetic susceptibility and specific heat. We interpret the ground state properties of the series of CeNi1−δSn1+δ−x Sb x compounds as resulting from the change in carrier number acting together with the hybridisation between the 4f electrons and the conduction electrons. For the Kondo semiconductor state we observe the scaling law χρ = const. of the susceptibility χ and the resistivity ρ, which is regarded as the basic feature for this class of materials, as was reported earlier. The magnetic properties of the system gradually evolve from the Kondo semimetallic state to the spin-glass behaviour when the Sb doping increases.

Thermal properties of La2/3Ba1/3(Mn1−xSbx)O3 manganites

Effects of Sb doping on thermal properties like thermoelectric power (S), thermal conductivity (κ), and specific heat (Cp) of La2/3Ba1/3(Mn1−xSbx)O3 (x=0.00–0.05) perovskite manganites are reported. It has been found that S is positive at low temperature and becomes negative at higher temperatures. A pronounced peak was observed in S at the insulator–metal transition for the pristine sample La2/3Ba1/3MnO3, which gets suppressed with Sb-doping. In addition, electron to hole-like crossover temperature seen in the S(T) is also found to move towards lower temperatures with increasing Sb content. The anomalous behavior in thermal conductivity (κ) at the transition is ascribed to the local anharmonic distortions associated with small polarons. The observed reduction of the total κ(T) due to Sb-doping is discussed with various thermal scattering mechanisms. From the specific heat results, broadening of observed sharp peak in the pristine LBMO data on substitution of Sb at Mn site was recognized as the enhancement of magnetic inhomogeneity in these manganites.

Effect of Sb doping on thermoelectric properties of chemically deposited bismuth selenide films

Bi 2− x Sb x Se 3 thin films with x = 0, 0.02, 0.04, 0.06, 0.08 and 0.10 were elaborated under optimum conditions using the arrested precipitation technique and their thermoelectric properties were studied as a function of Sb content ( x). The thermoelectric power and electrical conductivity measurement have been carried out on the films in the temperature range 300–500 K. Temperature-dependent electrical conductivity measurements verified semiconducting behaviour. From the thermoelectric power measurements it follows that the dominant carriers in all these films are holes. It was observed that thermal conductivity of Bi 2− x Sb x Se 3 film series decreases when the Sb content ( x) increases. The thermoelectric power factors of films have been found to be maximum for Bi 1.98Sb 0.02Se 3 composition at room temperature. Thermoelectric performance (ZT) in Bi 2− x Sb x Se 3 materials increases substantially at higher temperatures suggesting that these materials are promising for high temperature applications.

Effect of Sb doping on phase transition and relaxor behaviour of (Pb0.75Ba0.25)(Zr0.70Ti0.30)O3 ceramics

The effect of antimony dopant on phase transition, dielectric response and relaxor behaviour of (Pb0.75Ba0.25)(Zr0.70Ti0.30)O3 ceramics was studied. Ceramic samples, with various Sb concentration from the range 1 to 4 at.%, were prepared by a conventional mixed oxide method. The crystal structure of the investigated ceramics was determined by an X-ray diffraction at room temperature that allowed to determine the unit cell parameters. Dielectric relaxation typical for ferroelectric relaxors was observed in the vicinity of diffuse ferroelectric–paraelectric phase transition. All parameters describing the relaxor behaviour determined from the Vogel–Fulcher relationship depend on the concentration of Sb dopant. The strong influence of antimony on grain structure and on remanent polarisation was confirmed as well.

Structural and electrical properties of Sb-doped p-type ZnO thin films fabricated by RF magnetron sputtering

We investigated the Sb-doping effects on ZnO thin film using RF (radio frequency) magnetron sputtering and RTA (rapid thermal annealing). The structural and electrical properties of the thin films were measured by X-ray diffraction, SEM (scanning electron microscope), and Hall effect measurement. Thin films were deposited at a high temperature of 800°C in order to improve the crystal quality and were annealed for a short time of only 3 min. The structural properties of undoped and Sb-doped films were considerably improved by increasing oxygen content in the Ar-O2 gas mixture. Sb-doping also significantly decreased the electron concentration, making the films p-type. However, the crystallinity and surface roughness of the films degraded and the mobility decreased while increasing Sb-doping content, likely as a result of the formation of smaller grain size. From this study, we observed the transition to the p-type behavior at 1.5 at.% of Sb. The thin film deposited with this doping level showed a hole concentration of 4.412 × 1017 cm−3 and thus is considered applicable to p-type ZnO thin film.

Doping‐Dependent Electrical Characteristics of SnO2 Nanowires

Tin dioxide (SnO2) represents an importantmetal-oxide group that can be suitable for a range of applications through the incorporation of dopants. For example, the electrical conductivity of intrinsic SnO2 depends strongly on the surface properties, as molecular adsorption/desorption will affect the band modulation and space-charge layer, which makes SnO2 an important conductance-type gas-sensing material. On the other end of the doping spectrum, degenerately donor (such as Sb, Ta, and F) doped SnO2 films are important transparent conductive oxide (TCO) materials due to their large bandgap (3.6 eV) and high conductivity. SnO2-based TCO films are expected to be a low-cost alternative to indium tin oxide films in various optoelectronic devices, such as flat-panel displays, solar cells, and light-emitting diodes. Recent studies have also found that transition metal (such as Co and Ni) doped SnO2 acts as a diluted magnetic semiconductor and can exhibit Curie temperatures higher than room temperature. On the other hand, extending the doping processes from bulk SnO2 to nanostructures has been shown to be challenging due to both synthetic issues and ‘‘self-purification’’ mechanisms. In previous studies on SnO2 nanowires/nanobelts, the samples were not intentionally doped and the carriers typically originated from oxygen deficiencies. Intentional doping of SnO2 nanowires was reported recently by our group. Herein, we report systematic studies of the effect of Sb doping on SnO2 nanowires and detailed electrical characterization of the nanowire devices. Our results demonstrate that undoped SnO2 nanowires show Schottky contact to Ti/Au electrodes in air and are suitable for the detection of UV light. Lightly Sb-doped nanowires are promising as high-performance nanowire transistors, and degenerately Sb-doped SnO2

EXAFS investigation on Sb incorporation effects to electrical transport in SnO 2 thin films deposited by sol–gel

The effect of Sb doping in SnO 2 thin films prepared by the sol–gel dip-coating (SGDC) process is investigated. Electronic and structural properties are evaluated through synchrotron radiation measurements by EXAFS and XANES. These data indicate that antimony is in the oxidation state Sb 5+ and replaces tin atoms (Sn 4+), at a grain surface site. Although the substitution yields net free carrier concentration, the electrical conductivity is increased only slightly, because it is reduced by the high grain boundary scattering. The overall picture leads to a shortening of the grain boundary potential, where oxygen vacancies compensate for oxygen adsorbed species, decreasing the trapped charge at grain boundary.

Chemical shifts of atomic core levels and structure of K 1−xTi 1−xSb xOPO 4, x=0–0.23, solid solutions

Antimony-doped K 1− x Ti 1− x Sb x OPO 4, x = 0.23 , crystals have been prepared by spontaneous nucleation from the flux in the quaternary system K 2O–TiO 2–P 2O 5–Sb 2O 5. Crystal structure observation with TEM method reveals the presence of superstructure ordering. Core level electronic parameters have been studied by X-ray photoelectron spectroscopy. Strong effect of Sb doping has been detected for inner shells of Ti 4+ ions. Prominent decreasing of the binding energy difference Δ(O 1 s–Ti 2 p 3/2) correlates with the shortening of mean oxide bond length L(Ti−O) at x = 0.23 that suggests increased ionicity of Ti−O bonds in K 1− x Ti 1− x Sb x OPO 4 solid solutions.

Sb doping effects and oxygen adsorption in SnO2 thin films deposited via sol-gel

Transparent electrically conducting antimony-doped SnO2 thin films have been prepared by sol-gel dip-coating process from colloidal aqueous suspension. The effect of doping content on the structural, optical and electrical properties is analyzed. Results from infrared optical transmission and reflection have shown that the higher the Sb concentration the lower the transmission intensity and the higher the reflection signal. Absorption intensity increases as well. Results of X-ray reflectometry and electron microscopy have shown that the density of films fired at 400 °C after each dip is higher than that of multi-dipped films prepared with a single annealing. Both the electrical characteristics in the dark and the increase in conductivity as function of illumination through different filters, at 190 K, evidence that the transport properties of these films are dominated by the presence of defects, including the trapping at grain boundary due to excess of oxygen.