Ternary Samples Research Articles

Development of the internal matrix reinforcement bronze processed Nb3Sn multicore wires using Cu-Sn-In ternary alloy matrix for fusion magnet application

We approached the solid solution strength process for the high mechanical strength bronze processed Nb3Sn wires by the internal matrix reinforcement. Previously, we already reported the mechanical strength improvement of the Nb3Sn wire by the increasing of the amount of Zn element composition of the Cu-Sn-Zn ternary alloy matrix. However, there was also a trade-off relationship between the Sn and Zn compositions of the ternary matrix on the mechanical strength and superconducting properties. A Cu-Sn system ternary alloy containing Indium (In) element as a solute element (Cu-Sn-In), which is thought to be more effective solute element compared with Zn, was casted in order to improve mechanical strength beyond Cu-Sn-Zn ternary alloy matrix samples on the solid solution strength process. We fabricated various Cu-Sn-In-(Ti)/Nb precursor wires having 19 Nb multicores. The In element remained in the matrix after the Nb3Sn synthesis through the diffusion reaction, and then the Vickers hardness of the Cu-Sn-In matrices after the Nb3Sn synthesis heat treatment was higher than that of the conventional bronze and Cu-Sn-Zn matrices. We also confirmed that critical current density (Jc) property of the Nb3Sn wires using Cu-Sn-In-(Ti) was drastically increased at low and middle magnetic field below 15 T. These suggested that the In solute element in the matrix contributed the solid solution strengthening of the matrix after Nb3Sn synthesis and also improve Jc -B performance.

Novel ternary BiOI/g-C3N4/CeO2 catalysts for enhanced photocatalytic degradation of tetracycline under visible-light radiation via double charge transfer process

In this work, a novel visible-light-driven ternary BiOI/g-C3N4/CeO2 photocatalyst was successfully synthesized by calcination and hydrothermal treatment. The obtained ternary BiOI/g-C3N4/CeO2 had high photocatalytic performance for the degradation of tetracycline (TC) under visible-light irradiation. The samples were characterized by X-ray diffraction (XRD), UV–Vis diffuse reflectance (DRS) spectroscopy, and Fourier transform infrared spectroscopy (FT-IR), etc. The results indicated that 3 wt% BiOI/g-C3N4/CeO2 catalyst possessed the best photocatalytic activity (91.6%) among all the as-prepared samples. The enhanced photocatalytic activity could be attributed to a double charge transfer process between g-C3N4 and other catalysts in the ternary heterojunction, so that the separation of photogenerated electron–hole pairs was more effective. The as-prepared ternary sample also exhibited high stability after six cycles of the photodegradation reaction. Additionally, the active species (h+) were considered as the main reactive species during the degradation of TC. Based on the research results, a possible photocatalytic reaction mechanism for the BiOI/g-C3N4/CeO2 sample was proposed and discussed in detail.

Using DTA/DSC data for assessment of the Toop and Muggianu predictive models for the Ag–Au–In ternary

The relative performance of the Muggianu and Toop methods of preliminary prediction of thermodynamic properties of solution phases is tested using Ag–Au–In ternary as a model system, which was recently studied by the present authors. The temperatures of solids, monovariant reaction (where appropriate) and liquids, as well as the heat of melting of solid solutions, were measured by DTA/DSC for five ternary samples. Different extrapolation models generate very different descriptions of phase equilibria. However, accounting for ternary interactions brings all the results into moderately close agreement. In both methods, the values of ternary parameters for liquid phase are more negative than for solid phases (about twice in modulo in Muggianu one and up to ten times in Toop case). This implies the stabilization of liquid in central concentration region. Neither predictive model captures this without accounting for ternary interactions.

Transition Metal Elements as Ni/GDC Dopants for the H2O Electrolysis Process in SOECs: Fe-Ni vs Au-Mo-Ni Interaction

The presented study focuses on the effect of transition metal elements as dopants of the commercial NiO/GDC powder for the Solid Oxide H2O electrolysis. Specifically, the experimental comparison is between Au, Mo and Fe doping. Comparative electrocatalytic measurements with I-V curves and Electrochemical Impedance Spectra (EIS) analysis are presented in the range of 800-900 °C between electrolyte-supported cells with Ni/GDC, 3Au-3Mo-Ni/GDC and 2Fe-Ni/GDC, as the fuel electrode. In summary, the cell comprising the ternary 3Au-3Mo-Ni/GDC electrode performed significantly better while 2wt% Fe-Ni/GDC proved to be not successful. The superior performance of the Au-Mo-Ni ternary sample is primarily ascribed to the enrichment of the surface with Au and of the bulk phase with Mo, through the formation of Ni-Au-Mo solid solution. The involved elements modify the physicochemical properties of the electrode, improving the: (i) H2O re-oxidation rate, (ii) electronic conductivity and (iii) electrochemical interface. In regards to the Fe-doping, it is worth to be stressed that there are key preparation/modification parameters, which can tune the properties of Fe-Ni/GDC as a promising SOEC fuel electrode.

Ternary Gas Mixture Quantification Using Field Asymmetric Ion Mobility Spectrometry (FAIMS).

Gas mixture quantification is essential for the recording and reproducing odors, because an odor consists of multiple chemical compounds. Gas mixture quantification using field asymmetric ion mobility spectrometry (FAIMS) was studied. Acetone, ethanol, and diethyl ether were selected as components of a ternary gas mixture sample as representatives of the ketone, alcohol, and ether chemical classes, respectively. One hundred and twenty-five points with different concentrations were measured. The results were evaluated by error hypersurface, variance, and the coefficient of variation. The error hypersurface showed that it is possible to reach the target composition by following the error-hypersurface gradient. Successful convergence was achieved with the gradient descent method in a simulation based on the measurement data. This result verified the feasibility of the quantification of a gas mixture using FAIMS.

Robust strong electrospun polyimide composite nanofibers from a ternary polyamic acid blend

Electrospun polyimide (PI) nanofibers with excellent mechanical and thermal properties are highly required in composites, filtration, battery separators, proton exchange membranes, dielectric materials , oil-water separation, and functional sponges, because of their high mechanical strength, high porosity, good chemical and heat-resistance. In this work, a ternary polyamic acid composite precursor was used to achieve this aim. The resultant ternary PI aligned electrospun composite nanofibers (PI-AENFs) were composed of rigid moiety, soft moiety and pyrimidine-containing moiety. When the molar ratio was 40/36/24, the ternary composite PI-AENFs showed a highest tensile strength of 962 MPa, and a high modulus of 9.17 GPa. Because of the existence pyrimidine rings, the ternary composite PI-AENFs showed a 5% and 10% weight loss temperatures in the range of 537–551 °C and 577–583 °C, respectively. In addition, dynamic mechanical analysis indicated that the ternary composite PI-AENFs possessed good compatibility with each moiety because of the only one peak in the range of 294–333 °C in the dynamic mechanical analysis curves, suggesting a high glass transition temperature for all the ternary composite PI-AENF samples. These PI-AENFs with outstanding mechanical and thermal properties will provide good opportunity for applications in the high-temperature fields, such as filtration, fiber reinforced composites , battery, and so on. • Polyimide (PI) composite nanofibers from electrospinning a ternary polyamic acid blend. • Highest strength of 962 MPa and modulus of 9.12 GPa, when the ternary molar ratio is 40/36/24. • T 5% and T 10% were in the range of 537–551 °C and 577–583 °C, respectively. • Only one glass transition temperature in the range of 294–333 °C.

Fluidity enhancement of hard-to-fluidize nanoparticles by mixing with hydrophilic nanosilica and fluid catalytic cracking particles: Experimental and theoretical study

As a low-cost method, hydrophilic SiO2 nanoparticles (NPs) and fluid catalytic cracking (FCC) coarse particles were used as assistant materials to improve the fluidity of Al2O3 and TiO2 hard-to-fluidize nanopowders. To decrease the strong electrostatic forces between the hydrophilic nanopowders, prepared samples were fluidized in the presence of methanol vapor. Results revealed that the amount of SiO2 NPs, increased from 5 to 50 wt. %, has a beneficial effect on the fluidization quality of the binary (hard-to-fluidize NPs + SiO2) and ternary (hard-to-fluidize NPs + SiO2 + FCC) mixtures. However, the amount of FCC particles when it varied from 15 to 30 wt. % in the ternary mixtures should meet the optimal point, beyond which the fluidization quality was declined due to the segregation phenomenon. The laboratory results showed that the cost-effective ternary samples fluidized more homogeneously with higher bed expansions compared to the binary samples. In this regard, (Al2O3 + 20 wt. % SiO2) + 15 wt. % FCC and (TiO2 + 20 wt. % SiO2) + 15 wt. % FCC ternary samples were proposed as the alternatives of Al2O3 + 50 wt. % SiO2 and TiO2 + 50 wt. % SiO2 binary mixtures, respectively.

Thermo‐Rheology of a Proline‐Based Surface‐Active Ionic Liquid: Mixtures with Water and n‐Octane

AbstractSurfactant flooding is one of the most promising techniques to recover oil from unprofitable reservoirs. Surface‐active ionic liquids can overcome the limitations of the current surfactants. The rheology of the injecting solutions and the formed slugs is critical in the evaluation of an enhanced oil recovery process. The thermo‐rheological behavior of a biodegradable surface‐active ionic liquid, [ProC4]DS, and the corresponding binary and ternary mixtures with water and n‐octane was studied. All flow curves exhibited shear‐thinning and thixotropic behavior. The viscoelastic behavior of the ternary samples depended strongly on the [ProC4]DS content. Three different regions were identified: typical liquid‐like behavior, weak gel, and true gel. The thermal profiles indicated that the tested systems were fully thermoreversible.

Ag2S/MoS2 Nanocomposites Anchored on Reduced Graphene Oxide: Fast Interfacial Charge Transfer for Hydrogen Evolution Reaction

Hydrogen evolution reaction through electrolysis holds great potential as a clean, renewable, and sustainable energy source. Platinum-based catalysts are the most efficient to catalyze and convert water into molecular hydrogen; however, their large-scale application is prevented by scarcity and cost of Pt. In this work, we propose a new ternary composite of Ag2S, MoS2, and reduced graphene oxide (RGO) flakes via a one-pot synthesis. The RGO support assists the growth of two-dimensional MoS2 nanosheets partially covered by silver sulfides as revealed by high-resolution transmission electron microscopy. Compared with the bare MoS2 and MoS2/RGO, the Ag2S/MoS2 anchored on the RGO surface (the ternary system Ag2S/MoS2/RGO) demonstrated a high catalytic activity toward hydrogen evolution reaction (HER). Its superior electrochemical activity toward HER is evidenced by the positively shifted (-190 mV vs reversible hydrogen electrode (RHE)) overpotential at a current density of -10 mA/cm2 and a small Tafel slope (56 mV/dec) compared with a bare and binary system. The Ag2S/MoS2/RGO ternary catalyst at an overpotential of -200 mV demonstrated a turnover frequency equal to 0.38 s-1. Electrochemical impedance spectroscopy was applied to understand the charge-transfer resistance; the ternary sample shows a very small charge-transfer resistance (98 Ω) at -155 mV vs RHE. Such a large improvement can be attributed to the synergistic effect resulting from the enhanced active site density of both sulfides and to the improved electrical conductivity at the interfaces between MoS2 and Ag2S. This ternary catalyst opens up further optimization strategies to design a stable and cheap catalyst for hydrogen evolution reaction, which holds great promise for the development of a clean energy landscape.

Depth profile study of poly(styrene) – poly(methyl methacrylate) – tetrahydrofuran coatings

Raman binary calibration curves for poly(styrene) – tetrahydrofuran and poly(methyl methacrylate) – tetrahydrofuran were obtained from their prepared samples in sealed quartz vials. These binary calibration curves were successfully tested to calculate the amount of polymers and solvent in the prepared ternary samples of poly(styrene) – poly(methyl methacrylate) – tetrahydrofuran. These curves were used to measure the depth-dependent concentrations of polymers and solvents in dried poly(styrene) – poly(methyl methacrylate) – tetrahydrofuran coatings. The profile of tetrahydrofuran is found to be exponential in nature up to several microns from the substrate, then plateaus off, and then again decreases up to the surface. The same trend is also observed in the case of polymer concentration, but in the reverse order. The concentrations of polymers are low at the substrate and high at the surface. There is unequal distribution of polymers in the entire coating.

Synthesis and magnetic properties of Fe-Ni-Zn, Fe-Co-Zn and Co-Ni-Zn nanoparticles by co-precipitation method

In the present work, in order to investigate the effect of composition on the magnetic properties of nanoparticles, tri-metallic nanoparticles of Fe-Ni-Zn, Fe-Co-Zn and Co-Ni-Zn were prepared by co-precipitation method. Morphology of nanoparticles was studied by scanning electron microscopy technique (SEM). Also, the samples were characterized using resolution transmission electron microscopy (TEM). Structure of nanoparticles was characterized by powder X-ray diffraction (XRD). Magnetic properties of bulk and nanostructures were studied at room temperature with applied magnetic fields up to 10000 Oe with vibrating sample magnetometer (VSM). The ternary bulk samples of Fe-Ni-Zn, Fe-Co-Zn and Co-Ni-Zn as precursor showed paramagnetic behavior. After calcination, tri-metallic nanoparticles of Fe-Ni-Zn, Fe-Co-Zn and Co-Ni-Zn exhibited superparamagnetic, soft ferromagnetic and hard ferromagnetic behavior respectively.

Affecting the H2O electrolysis process in SOECs through modification of NiO/GDC; experimental case of Au-Mo-Ni synergy

This is a study on how the Solid Oxide Cell H2O electrolysis can be affected, through modification of commercial NiO/GDC powder and the experimental case focuses on the effect of Au/Mo doping. Physicochemical characterization is presented, in which the samples were examined both in the form of powders and as half cells with BET, HR-TEM/EDS, SEM, in-situ H2-XPS and specific re-oxidation TG analysis in the presence of H2O. Furthermore, there are comparative electrocatalytic measurements, under various pH2O/pH2 ratios (from 1 to 9) in the temperature range of 800–900 °C. The latter include I-V measurements and Electrochemical Impedance Spectra (EIS) analysis of single electrolyte supported cells with Ni/GDC, 3 wt% Au-Ni/GDC, 3 wt% Mo-Ni/GDC and 3 wt% Au – 3 wt% Mo-Ni/GDC, as the steam/hydrogen electrode. In particular, the cell comprising the ternary cathode performed significantly better, compared to the (Au-, Mo-) binary electrodes and Ni/GDC. The superior performance of the ternary sample is primarily ascribed to the enrichment of the surface with Au and of the bulk phase with Mo, through the formation of Ni-Au-Mo solid solution. The involved elements act in synergy and modify the physicochemical properties of the electrode, improving the: (i) H2O re-oxidation rate, (ii) electronic conductivity and (iii) electrochemical electrode/electrolyte interface. Indicatively, the polarization resistance (Rpol) terms of the ternary electrode, exhibited the lowest values and most importantly showed negligible degradation, by increasing the pH2O/pH2 ratio. It is worth mentioned that the presented study corroborates our recently published approach in which H2O, apart from the reactant of the process, is also acknowledged as a potential poisoning agent. Hence, proper modification of Ni/GDC should aim to the selectively weak interaction of H2Oads with the electrode, towards the inhibition of the re-oxidation rate of Ni in favor of the direct electrochemical splitting of H2O.

Structural, elastic and optoelectronic characteristics of BexZn1−xS, BexZn1−xSe and BexZn1−xTe alloys-a density functional based FP-LAPW study

Structural, elastic and optoelectronic features of BexZn1−xS, BexZn1−xSe and BexZn1−xTe alloys are computed employing DFT based FP-LAPW approach. Structural features with WC-GGA functional show that lattice constant decrease and bulk modulus increase nonlinearly with increase in Be-concentration in each alloy system. The elastic constants C11andC44for cubic specimens increase, whileC12decrease with increase in Be-concentration in each system. Elastically anisotropic specimens at x = 0.0 and 0.25 are ductile, while at x = 0.50, 0.75 and 1.0 are brittle in nature. The electronic properties, computed with mBJ, EV-GGA and PBE-GGA functional, predict each ternary sample as a direct band gap (Γ-Γ) semiconductor. Band gap increases nonlinearly with Be-concentration in each system. Chemical bonding between beryllium and chalcogen are ionic and between zinc and chalcogen are covalent in nature. In optical transitions, chalcogen-p in valence band as initial states and Be-3s, 2p as well as Zn-5s states in conduction band as final states play the leading role. Nature of variation of each of theε1(0), n(0)and R(0)with Be-concentration x is opposite, while critical point in each of the ε2(ω)k(ω),σ(ω) and α(ω) spectra with Be-concentration x is similar to the nature of variation of band gap with Be-concentration in each alloy system.

Density functional study of structural, elastic, electronic and optical properties of BexCd1−xS, BexCd1−xSe and BexCd1−xTe alloys using FP-LAPW approach

Structural, elastic, electronic and optical features of cadmium-beryllium-chalcogenide ternary alloys BexCd1−xS, BexCd1−xSe and BexCd1−xTe have been computed employing density functional theory (DFT) based FP-LAPW approach. Structural features have been computed with Wu-Cohen (WC)-GGA functional and found that the lattice constant decreases, while bulk modulus increases nonlinearly with Be-concentration in each alloy system. Each of the elastic constants C11, C12 and C44 for the cubic specimens in each alloy system increases with in Be-concentration. Moreover, each specimen shows elastic anisotropy. Specimens at x = 0.0 and 0.25 are found to be ductile in nature, while those at x = 0.50, 0.75 and 1.0 show brittle nature. The electronic properties are explored with the modified Becke-Johnson (mBJ), Engel-Vosko (EV)-GGA and Perdew-Burke-Ernzerhof (PBE)-GGA functional and found that each ternary sample is a direct band gap (Γ-Γ) semiconductor. Band gap for each alloy system increases nonlinearly with Be-concentration. Chemical bonding between beryllium and chalcogen are ionic and that between cadmium and chalcogen are covalent in nature. In case of optical transitions, the chalcogen-p of valence band as initial states and Be-3s, 2p as well as Cd-6s states of conduction band as final states play the dominant role. In each alloy system, nature of variation of each of the static dielectric constant, static refractive index and static reflectivity with Be-concentration x is opposite, while critical point in each of the ε2(ω), k(ω), σ(ω) and α(ω) spectra with Be-concentration x is similar to the nature of variation of band gap with Be-concentration. Several calculated properties are found to agree well with the corresponding experimental findings.

Density functional calculations of structural, elastic and optoelectronic features of Mg Zn1−S, Mg Zn1−Se and Mg Zn1−Te alloys

Abstract Structural, elastic, electronic and optical features of zinc-magnesium-chalcogenide ternary alloys MgxZn1−xS, MgxZn1−xSe and MgxZn1−xTe have been explored theoretically employing density functional theory based FP-LAPW approach. Structural features have been computed with Wu-Cohen (WC)-GGA functional and found that lattice constant increases, while bulk modulus decreases nonlinearly with increase in Mg-concentration x in each alloy system. Each of the elastic constants C 11 , C 12 and C 44 for the cubic specimens decreases with increase in Mg-concentration x in each alloy system. Moreover, each specimen shows elastic anisotropy and found to be ductile in nature. The electronic properties are explored with the modified Becke-Johnson (mBJ), Engel-Vosko (EV)-GGA and Perdew-Burke-Ernzerhof (PBE)-GGA functional and found that each binary and ternary sample is a direct band gap (Γ-Γ) semiconductor. Band gap for each alloy system increases nonlinearly with Mg-concentration x. Chemical bonding between magnesium and chalcogen are ionic, while that between zinc and chalcogen are covalent in nature. In case of optical transitions, the chalcogen-p of valence band as initial states and Mg-4s, 3p as well as Zn-5s, 4p of conduction band as final states play the dominant role. In each alloy system, nature of variation of each of the static dielectric constant, static refractive index and static reflectivity with Mg-concentration x is opposite, while that of critical point in each of the e 2 ( ω ) , k ( ω ) , σ ( ω ) and α ( ω ) spectra with Mg-concentration x is similar to the nature of variation of band gap with Mg-concentration x. Several calculated properties are found to agree well with the corresponding experimental findings.

Influence of EVA-g-MAH compatibilizer on adhesion strength, mechanical properties and thermal behavior of EVA/SBS hot melt adhesive blends

Hot melt adhesives (HMAs) were prepared by compounding ethylene vinyl acetate copolymers (EVA) and styrene-butadiene-styrene block copolymer (SBS). To enhance the compatibility of EVA and SBS, different proportions of EVA-g-MAH were added as compatibilizers. The thermal behavior, rheological properties and adhesion of the EVA/EVA-g-MAH/SBS ternary blends have been systematically investigated. The results revealed that the melt viscosity increased with the addition of EVA-g-MAH, whereas the mechanical strength initially increased with the addition of EVA-g-MAH up to a threshold value (6 wt%), followed by a gradual decrease. These results are consistent with the SEM observations. The adhesion strength of the EVA/EVA-g-MAH/SBS ternary samples was assessed by 180° peeling test of cotton strip/adhesives/stainless steel stack. The results revealed that adhesion performance and compatibility of EVA/SBS composite HMAs were greatly improved due to the addition of EVA-g-MAH. In addition, the sample containing 6 wt% EVA-g-MAH exhibited excellent adhesion performance and optimal compatibility. The peeling strength reached a maximum value of 36 N mm−1 with cohesive failure mode, which corresponds to a 33.3% increase as compared to the system without compatibilizer.

Preparation and optimization of ultra-light and thermal insulative aerogel foam concrete

Lightweight and thermal insulative foam concrete has gathered increasing interests in buildings for energy efficiency. However, their density (∼400 kg/m3) and thermal conductivity (0.10 W/(m·K)) need to be further decreased for high performance applications in green and nearly zero energy buildings. A novel type of aerogel foam concrete with a low density of 198 kg/m3 and thermal conductivity of 0.049 W/(m·K) was successfully fabricated by adding super-insulative and Nano-porous aerogels into micro-porous foam concrete. The microstructure and thermal conductivity of the aerogel foam concrete were experimentally investigated. A model was established for predicting the thermal conductivity of the aerogel foam concrete based on a modified Maxwell model. The calculated results were validated with experimental data, with an error of less than 5%. By using the model, the effects of the ternary ratios on the thermal conductivity were investigated, and the optimization aiming at the minimum thermal conductivity was then implemented. Accordingly, a ternary aerogel foam concrete sample with the optimal ratios was experimentally prepared, whose thermal conductivity and density were approximately 50% lower than those of existing foam concrete. Therefore, the novel type aerogel foam concrete, yielding high performance, could be extensively used for potential applications in green and nearly zero-energy consumption buildings.

Thermodynamic stability of the fluorite phase in the CeO2 − CaO − ZrO2 system

The fluorite phase in CeO2 − CaO − ZrO2 is important in nuclear energy and fuel cell applications yet one lacks quantitative evaluation of its composition range and thermodynamic properties. Using experimental thermodynamic data from binary systems ZrO2 − CeO2, CaO − CeO2 and CaO − ZrO2, the present work fitted the enthalpies of mixing to regular solid solution models. The interaction parameters for binary systems are ΩCeO2-ZrO2 = 49.9 ± 2.4 kJ mol−1, ΩCaO-ZrO2 = −78.0 ± 16.7 kJ mol−1 and ΩCaO-CeO2 = 53.1 ± 21.5 kJ mol−1. Enthalpies of transformation of monoclinic zirconia to the cubic fluorite phase (stable at high temperature) and of rocksalt calcia to the hypothetical fluorite phase were constrained by experimental data. Enthalpies of mixing in the ternary CeO2 − CaO − ZrO2 system were calculated from enthalpies of drop solution measured by high temperature oxide melt solution calorimetry for a set of newly synthesized ternary fluorite samples. Comparison of measured values with those predicted from the binary systems using the Kohler equation suggests that the ternary excess term is zero within experimental error. Thus simple equations could be derived for heats of formation, mixing and phase transition in this system which can be used in the future in CALPHAD type calculations of phase equilibria that obtain the extent of fluorite solid solution at different temperatures.

Interfacial reactions in the Co/In/Cu and Ni/In/Cu samples

Abstract To provide fundamental understanding for the solid-liquid interdiffusion process using indium-based solders, interfacial reactions in the Co/In, In/Cu, Ni/In, Co/In/Cu and Ni/In/Cu samples at the Co/In, In/Cu and Ni/In interfaces are systematically determined. CoIn3 phase is formed in the Co/In couples reacted at 200, 350 and 500 °C. Cu11In9 and a two-phase mixture region are observed in the In/Cu couples reacted 200 °C, and δ-Cu7In3 and η'-Cu2In phases are found at 350 and 500 °C. In the Ni/In couples, the In7Ni3 phase is formed at 200 and 350 °C, while InNi and In3Ni2 phases are found at 500 °C. Except for the formation of an unknown ternary phase in the Co/In/Cu sample reacted at 350 °C, the reaction phases in the sandwich-type ternary samples are the same as those in the binary couples, and no significant cross- interactions are observed both in Co/In/Cu and Ni/In/Cu samples. The indium consumption rates are faster in the Ni/In/Cu samples. Their consumption rates are estimated based on the indium accumulation in the reaction phases.

Comparison study of temperature dependent direct/indirect bandgap emissions of Ge1-x-ySixSny and Ge1-ySny grown on Ge buffered Si

Temperature-dependent photoluminescence (PL) of two sets of ternary samples with fixed tin concentrations of ~5.2% (Ge0.924Si0.024Sn0.052, and Ge0.911Si0.036Sn0.053) and ~7.3% (Ge0.900Si0.027Sn0.073, and Ge0.888Si0.04Sn0.072) were measured along with their binary counterparts (Ge0.948Sn0.052 and Ge0.925Sn0.075). The variations of direct bandgap emission (ED) and indirect bandgap emission (EID) with temperature were studied for both ternary and binary alloys by means of Gaussian curve fitting, and the results are compared. The bandgap widths of ternaries clearly increase after Si incorporation into the GeSn with similar Sn concentrations. It is found that for the ternaries both ED and EID peak energies are blue shifted, and the energy separation of ED and EID peaks becomes larger than that of binaries for similar Sn concentrations. Moreover, both ED and EID peaks appear at room temperature (RT) in the GeSiSn spectra, but the ED peak position is greater than EID, indicating these ternaries are indirect bandgap materials. Low temperature PL validates the existence of indirect PL emission in Ge0.90Si0.027Sn0.073 and direct gap behavior in Ge0.925Sn0.075, indicating GeSn becomes a direct bandgap material at lower Sn concentration than GeSiSn. The PL intensities of these ternaries are generally weaker and the spectra become more complicated than those of binaries, probably due to increased strain and defects in the ternaries. Finally, it is found that the effect of large differences in strain of ternary samples on PL peak positions can be greater than that of small Si composition differences in ternaries. A large compressive strain in ternaries can also make splitting of the ED into ED,HH (conduction band minimum-Γ valley to heavy hole maximum) and ED,LH (conduction band minimum-Γ valley to light hole maximum) transitions more observable in the PL spectra.