Low Sn Content Research Articles

The [100] direction strained Ge[formula omitted]Snx nanowires with low Sn contents towards the application of SWIR or MWIR lasers

The band structures of Ge1−xSnx nanowires with low Sn contents at the Γ-valley and L-valley under the [100] direction stress are studied via effective-mass theory, and we find that Ge0.95Sn0.05 and Ge0.92Sn0.08 nanowires can be tuned to direct-bandgap semiconductors even for the stress less than 4 GPa. Moreover, as increasing the stress, the calculations of the optical gain manifest that the z direction peak gain can be enhanced sharply regardless of the diameter and Sn content since more electrons are filled at the Γ-valley. The further research shows that the FCA loss of Ge1−xSnx nanowires can almost be neglected, meanwhile remarkable and positive net peak gain along the z direction can be acquired even though electron concentration is as low as the order of 1018 cm−3, which can overcome the non-negligible FCA loss caused by electron concentration of the order of 1019 cm−3 in Ge or strain-free Ge1−xSnx nanowires.

Influence of tin additions on the corrosion passivation of TiZrTa alloy in sodium chloride solutions

Abstract In this study, the fabrication of Ti-12%Zr-4%Ta-2%Sn alloy, Ti-12%Zr-4%Ta-4%Sn alloy, and Ti-12%Zr-4%Ta-6%Sn alloy using powder metallurgy fabrication technique has been carried out. The influence of Sn addition on the corrosion of these alloys after 30 min and 3 days in 3.5% NaCl solution using various techniques has been reported. The Nyquist spectra revealed that boosting Sn content from 2 to 4% and further to 6% increases the corrosion resistance of the alloy through increasing the diameter of the obtained semicircle. Bode spectra also elucidated that the increased percentage of Sn increases the values of the impedance of the interface |Z| and the maximum degree of the phase angle (Φ). It was indicated from the cyclic polarization curves that the increased Sn content increases the passivation of the alloy through decreasing its rate of corrosion and increasing its corrosion resistance. The measured current over time at −0.10 V showed that the alloy with low Sn content, 2%, records the highest currents, which pronouncedly decreases when Sn content increases to 4% and further to 6%. Prolonging the time of exposure from 30 min to 3 days greatly enhances the passivation of the TiZrTaSn alloys due to the formation of mixed oxides of TiO2, ZrO2, TaO2, and SnO2. The results of these electrochemical measurements were confirmed by the surface investigations carried out by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results collectively proved that the uniform corrosion remarkably decreases with the increase in the Sn% and that the pitting corrosion is not likely to take place.

Magmatic–Hydrothermal Evolution at the Barren Wushan Pluton, Southeast China: Insight into Controls on Mineralization Potential

Abstract A-type granites typically exhibit enrichment and mineralization of critical metals such as molybdenum and tin, essential for emerging technologies. However, the key factors influencing their mineralization potential remain elusive. The scarcity of studies on barren systems impedes the understanding of this question. Here, a detailed melt and fluid inclusion study was conducted on the barren Wushan pluton to reconstruct its magmatic evolution and magmatic–hydrothermal transition and explore the factors controlling the metallogenic potential of Mo and Sn in A-type granites. The Wushan pluton displays apparent lithological zoning consisting of two major phases, i.e., medium-grained seriate to porphyritic alkali feldspar granite and fine-grained porphyritic granite. Miarolitic cavities are widely developed in each lithofacies. The silicate melt inclusions from two granitic phases are rhyolitic, with moderate F contents (0.06–0.53 wt %) and depleted H2O contents (2.0–3.5 wt %). Melt inclusions show a wide range of incompatible element contents, such as Cs (9–1977 μg/g) and Rb (268–2601 μg/g), suggesting that Wushan has undergone a high degree of magma evolution. Mo behaves incompatibly in the magmatic evolution, and its content is enriched with the increasing degree of fractional crystallization, but remains constant after the Cs content exceeds 50 μg/g. Rayleigh fractionation model suggests that a large amount of Mo is extracted from fluid exsolution, which restrains Mo from further enrichment. In contrast, Sn behaves as a mildly incompatible element during the entire magmatic evolution history. The contents of Sn increase slowly compared to the trend of Mo, and the maximum contents reach ~30 μg/g in the highly evolved melts. The separation and crystallization of Sn-bearing minerals such as biotite, magnetite, and titanite inhibit the enrichment of Sn. Intermediate-density (ID-type) fluid inclusions hosted in the miarolitic quartz, representing the initial fluid exsolving from magma, display high Mo but low Sn concentrations. Constrained from two assemblages of coexisting ID-type fluid and melt inclusions, the fluid/melt partition coefficients of metals are obtained, with DMo, fluid/melt at 16–19, while DSn, fluid/melt is only about 1. The comparison between Mo-mineralized and barren intrusions worldwide shows that the metal contents in melts and fluids are not fundamentally different. The mineralized intrusions are characterized by the lower melt viscosity and the development of apophyses, both of which facilitate the extraction of metals and fluids from large magma chambers, followed by their concentration into a small rock volume. Consequently, it appears that physical and structural conditions rather than chemical compositions play a crucial role in the Mo mineralization process. Enrichment of Sn in melts is necessary but not decisive for Sn mineralization, whereas Sn enrichment in the initial exsolving fluid determines the Sn mineralization potential of a given granitic system. Compared to Sn enrichment in source melting and fractional crystallization which commonly enhance final Sn fertility in the highly evolved melts, the efficiency of Sn partitioning between melt and fluid plays a fundamental role in converting melt fertility into Sn-enriched fluids and thereby high mineralization potential of the magmatic–hydrothermal system. Our findings suggest a prospect for Mo exploration in the coastal A-type granite belt in South China, while the potential for Sn mineralization is expected to be limited.

High-precision MC-ICP-MS measurements of Cd isotopes using a novel double spike method without Sn isobaric interference

Previous studies have reported that even low concentrations of Sn can lead to biased Cd isotopic measurements using MC-ICP-MS. In this paper, we propose a novel method of Cd isotopic...

Tracing tungsten-tin mineralization processes with tourmaline geochemistry in the Wangxianling-Hehuaping district, Nanling Range (South China)

The mechanisms controlling the enrichment and separate precipitation of tungsten and tin ores are obscure. To unravel the physicochemical changes in the mineralization system during the magmatic-hydrothermal transition, we investigate the petrography, geochemistry, and boron isotopes of tourmaline in the Wangxianling-Hehuaping district (Nanling Range, South China). Four types of tourmalines were identified: Magmatic (Tur-WG) and hydrothermal (Tur-WV) tourmaline in the Triassic W-mineralized tourmaline-two-mica granite (ca. 220 Ma); Magmatic (Tur-SnG) and hydrothermal (Tur-SnV) tourmaline in the Jurassic Sn-mineralized biotite granite (ca. 155 Ma). Tur-WV and Tur-SnV have lower Fe3+/(Fe2+ + Fe3+) ratios than those of Tur-WG and Tur-SnG, suggesting that W-Sn mineralization occurred in a relatively reducing environment. In addition, the δ11B values of all four types of tourmalines are similar, suggesting that the ore-forming fluids were primarily exsolved from the granitic magma. Significant chemical variations (e.g., Mg, Fe, Sc, V, Ni, and REEs) between Tur-SnG and Tur-SnV may have been resulted from fractionation and intense ore fluid-wall rock reactions. In contrast, Tur-WG has similar chemical compositions to Tur-WV, suggesting that the Triassic W mineralization may have undergone a magmatic-hydrothermal process with little ore fluid-wall reaction. Tur-SnV has exceptionally high F content, which could enhance the Sn solubility and enrichment. This explains the low Sn content of granitic magmas with large-scale Jurassic tin mineralization. Considering that W has a large melt-fluid partition coefficient, we conclude that in the Triassic, W is enriched in the exsolved fluid from the granitic magma and precipitated with temperature drop. This may have caused the decrease in W content in the protolith and limited the Jurassic W mineralization. Subsequently, the mantle-derived F addition along the Chenzhou-Linwu fault in the Jurassic had led to Sn enrichment in the fluids, and mineralization is triggered by temperature drop and fluid-rock reactions. Eventually, the extensive Triassic W mineralization and Jurassic Sn mineralization exhibit the separation of tungsten-tin mineralization. The separated tungsten-tin mineralization model based on different volatile components could also be applicable to other tungsten-tin metallogenic belts.

Dark Current Analysis on GeSn p-i-n Photodetectors.

Group IV alloys of GeSn have been extensively investigated as a competing material alternative in shortwave-to-mid-infrared photodetectors (PDs). The relatively large defect densities present in GeSn alloys are the major challenge in developing practical devices, owing to the low-temperature growth and lattice mismatch with Si or Ge substrates. In this paper, we comprehensively analyze the impact of defects on the performance of GeSn p-i-n homojunction PDs. We first present our theoretical models to calculate various contributing components of the dark current, including minority carrier diffusion in p- and n-regions, carrier generation-recombination in the active intrinsic region, and the tunneling effect. We then analyze the effect of defect density in the GeSn active region on carrier mobilities, scattering times, and the dark current. A higher defect density increases the dark current, resulting in a reduction in the detectivity of GeSn p-i-n PDs. In addition, at low Sn concentrations, defect-related dark current density is dominant, while the generation dark current becomes dominant at a higher Sn content. These results point to the importance of minimizing defect densities in the GeSn material growth and device processing, particularly for higher Sn compositions necessary to expand the cutoff wavelength to mid- and long-wave infrared regime. Moreover, a comparative study indicates that further improvement of the material quality and optimization of device structure reduces the dark current and thereby increases the detectivity. This study provides more realistic expectations and guidelines for evaluating GeSn p-i-n PDs as a competitor to the III-V- and II-VI-based infrared PDs currently on the commercial market.

Improving mechanical properties of Mg-Sn alloys by co-addition of Li and Al

In this work, a novel low-alloyed Mg-Sn-Li-Al alloy with high-strength has been developed. The addition of ∼1 ​wt% Li into the Mg-2Sn wt.% binary alloy can change the type of strengthening phases in Mg-2Sn-1Li sample (TL21), involving the formation of both Li2MgSn and Mg2Sn phases. The co-addition of ∼1 ​wt% Al and ∼1 ​wt% Li can further induce the higher density of both micron-sized phases and nano-precipitations in the Mg-2Sn-1Li-1Al sample (TLA211). The nano-precipitations can inhibit the grain growth, which thus lead to the fine grain size of ∼1.38 ​μm in TLA211 sample, and ∼1.59 ​μm in the TL21 sample. Besides, the profuse nano-phases would improve the yield strength via Orowan hardening effect. Consequently, the TL21 sample can exhibit the high yield strength of ∼204 ​MPa, and elongation of ∼6.6%. The TLA211 sample exhibits the much higher yield strength of ∼250 ​MPa, ultimate tensile strength of ∼291 ​MPa, and also high elongation of ∼9.0%. The high strength-ductility synergy, together with the low-Sn content, make the present Mg-Sn based alloy to be potential for the wider industrial applications.

Evolution of microstructure and properties of an ultrahigh strength Cu–Ni–Sn alloy with low Sn content during the multi-stage thermomechanical treatment

An ultrahigh strength Cu–9Ni-1.5Sn-0.8Si-0.1Al alloy was designed. The effect of multi-stage thermomechanical treatment on the evolution of the microstructure and the properties of designed alloy is explored. The alloy treated by cold rolled (60%)-pre-aging (400 °C/30 min)-cold rolled (50%)-450 °C/120 min-cold rolled (50%)-330 °C/120 min had a tensile strength of 1150 MPa and remained electrical conductivity of 18.1 %IACS. Nanoscale β′-Ni3Sn, β-Ni3Si, γ′-Ni3Al precipitates formed during the thermomechanical treatment. The Cu matrix and precipitates maintain an orientation relationship (OR) were [111]Cu//[111]p and [200]Cu//[200]p. More than half of the ultra-high strength of the design alloy is contributed by precipitation strengthening. The multi-stage thermomechanical treatment further improves mechanical and electrically conductivity properties of Cu–Ni–Sn alloy compared to the single-stage aging treatment. The synergistic impact of nanoparticles formed on heat treatment and dislocations formed on deformation further promoted the precipitation of Ni3X (X = Sn, Si, Al) in the matrix.

Formation and Morphological Transition of Diversified Eutectic Structures in Ag-Based Brazing Filler Metals with Sn Addition

Eutectic structures in Ag-based brazing filler metals play an important role in improving the properties of alloys and brazed joints. The typical microstructures and morphological evolution of Ag-Cu eutectic structures in Ag-based brazing filler metals solidified at various cooling rates and with the addition of different Sn contents were investigated. The formation mechanisms of anomalous eutectic structure (AES) and the morphological transition from lamellar eutectic structure (LES) to AES were elucidated. The microstructures in alloys solidified at a slow cooling rate and with low Sn content consisted of the full AES, which was attributed to the remelting of the LES during recalescence. Increasing the Sn content and cooling rate promoted the formation of developed Ag dendrite, eutectic dendrite with branches, and AES with large dimensions. The AES in rapidly solidified filler metals with a high Sn content was ascribed to the decomposition of the Ag-rich dendrite skeleton and the growth of Cu-rich between the ternary dendrite arms.

Gesn Alloys: From Optical to Electrical Pumped Lasers

Internet of Things applications, including medical diagnostics, imaging and industrial process controls, pollution monitoring or real-time motion control, push the extension of the Si photonics towards mid-infrared range.In recent years, group IV SiGeSn-based optoelectronic devices including light emitting, detectors, modulators, and CMOS devices have been developed. The main advantage of SiGeSn is the bandgap tunability in the range between 1.5 to 5 µm via Si and Sn compositions. Remarkably, the GeSn binary alloy becomes a direct bandgap semiconductor at a relative low Sn content of about 7-8 at.% opening the quest for the realization of monolithically integrated laser sources on Si. In this direction, from the first laser emission proof in 2015 remarkable progress has been done. Supported by epitaxial growth success, processing technology, and cavity design, the laser emission of optically pumped was continuously increased from 80K to 270K. The main role here was played by increasing the Sn content up a concentration of 17 at.%.The next major improvement came from layer transfer technology allowing defect engineering and heat management. Their combination made possible room temperature lasing. However, the real life application requires low laser threshold. Here the use of multiple quantum wells based on SiGeSn/GeSn heterostructures and strain engineering allow a remarkable threshold reduction to values of about 1 kA/cm2. Interestingly, modeling shows that the very epitaxial challenging of having high Sn contents can be reduced by band structure engineering via introducing tensile strain and, in addition, larger gains are possible compared with high-Sn strain free layers. The optical laser spectrum at 0 °C for a GeSn layer under 1 % biaxial tensile strain is shown in Fig 1a.The next step is the realization of an electrical pumped GeSn laser. The first data indicate that both waveguide and microdisk cavities can be electrically pumped leading to low temperature laser emission. The effect of the geometry and strain relaxation of under-etched cavities on the laser emission is under study. Figure 1b shows an exemplary spectrum and current-in light-out (LI) curve for a device with a SiGeSn/GeSn heterostructure taken at 50 K. Figure 1

Thermoelectric Performance of Sn and Bi Double-Doped Permingeatite

In this study, mechanical alloying was performed to synthesize permingeatite Cu3Sb1-x-ySnxBiySe4 (0.02 ≤ x ≤ 0.06 and 0.02 ≤ y ≤ 0.04) doped with Sn and Bi. Hot pressing was subsequently conducted to achieve dense sintered bodies. When the Bi content was constant, the carrier concentration increased with the Sn content, but the mobility decreased owing to the increased carrier concentration. In contrast, when the Sn content was constant, the carrier concentration and mobility were not significantly affected by the Bi content. Higher electrical conductivity was observed in specimens with a higher Sn content or lower Bi content; consequently, Cu3Sb0.92Sn0.06Bi0.02Se4 exhibited the highest electrical conductivity. The Seebeck coefficient increased with temperature, and it is inferred that the permingeatite doped with Sn/Bi does not undergo an intrinsic transition until 623 K. In contrast to the electrical conductivity, a higher Seebeck coefficient was obtained in the specimens with a lower Sn content or higher Bi content; consequently, Cu3Sb0.94Sn0.02Bi0.04Se4 exhibited the highest Seebeck coefficient. Cu3Sb0.92Sn0.06Bi0.02Se4 exhibited the maximum power factor, depending on the electrical conductivity and Seebeck coefficient. The electronic thermal conductivity was not significantly affected by temperature, but the lattice thermal conductivity decreased as the temperature increased. However, the thermal conductivity decreased with increasing temperature. Sn doping effectively reduced the lattice thermal conductivity, whereas Bi doping effectively reduced the electronic thermal conductivity; consequently, Cu3Sb0.94Sn0.02Bi0.04Se4 exhibited the lowest thermal conductivity. Finally, the highest dimensionless figure-of-merit of 0.75 was achieved at 623 K by Cu3Sb0.92Sn0.06Bi0.02Se4.

Sn-incorporation effect on thermoelectric properties of Sb-doped Ge-rich Ge1−x−y Si x Sn y epitaxial layers grown on GaAs(001)

We investigate Sn incorporation effects on the thermoelectrical characteristics of n-type Ge-rich Ge1−x−y Si x Sn y layers (x ≈ 0.05−0.1, y ≈ 0.03) pseudomorphically grown on semi-insulating GaAs(001) substrates by molecular beam epitaxy. Despite the low Sn content of 3%, the Sn atoms play a role in suppressing the thermal conductivity from 13.5 to 9.0 Wm−1 K−1 without degradation of the electrical conductivity and the Seebeck coefficient. Furthermore, a relatively high power factor (maximum: 14 μW cm−1 K−2 at room temperature) was also achieved for the Ge1−x−y Si x Sn y layers, almost the same as the Si1−x Ge x ones (maximum: 12 μW cm−1 K−2 at room temperature) grown with the same conditions. This result opens up the possibility of developing Sn-incorporated group-IV thermoelectric devices.

Effects of Electroless NiSnP Plating Bath Composition with High Sn Containing Deposited Film

Many studies have investigated Ni-Sn alloy because it has good luster and excellent corrosion resistance. Electroplating methods have already reached a practical level of applicability, but electroless plating methods have not reached such a degree of utility because they present difficulties such as insufficient film thickness and low Sn content in the deposited film. Therefore, we fixed the bath temperature and stirring under the operating conditions and studied details of the plating bath composition to deposit a film with a high Sn content of 50 wt% or more using electroless plating.

Enhancing the incorporation of Sn in vapor–liquid–solid GeSn nanowires by modulation of the droplet composition

We report on the influence of the liquid droplet composition on the Sn incorporation in GeSn nanowires (NWs) grown by the vapor−liquid−solid (VLS) mechanism with different catalysts. The variation of the NW growth rate and morphology with the growth temperature is investigated and 400 °C is identified as the best temperature to grow the longest untapered NWs with a growth rate of 520 nm min−1. When GeSn NWs are grown with pure Au droplets, we observe a core–shell like structure with a low Sn concentration of less than 2% in the NW core regardless of the growth temperature. We then investigate the impact of adding different fractions of Ag, Al, Ga and Si to Au catalyst on the incorporation of Sn. A significant improvement of Sn incorporation up to 9% is obtained using 75:25 Au–Al catalyst, with a high degree of spatial homogeneity across the NW volume. Thermodynamic model based on the energy minimization at the solid–liquid interface is developed, showing a good correlation with the data. These results can be useful for obtaining technologically important GeSn material with a high Sn content and, more generally, for tuning the composition of VLS NWs in other material systems.

SiGeSn Quantum Dots in HfO2 for Floating Gate Memory Capacitors

Group IV quantum dots (QDs) in HfO2 are attractive for non-volatile memories (NVMs) due to complementary metal-oxide semiconductor (CMOS) compatibility. Besides the role of charge storage centers, SiGeSn QDs have the advantage of a low thermal budget for formation, because Sn presence decreases crystallization temperature, while Si ensures higher thermal stability. In this paper, we prepare MOS capacitors based on 3-layer stacks of gate HfO2/floating gate of SiGeSn QDs in HfO2/tunnel HfO2/p-Si obtained by magnetron sputtering deposition followed by rapid thermal annealing (RTA) for nanocrystallization. Crystalline structure, morphology, and composition studies by cross-section transmission electron microscopy and X-ray diffraction correlated with Raman spectroscopy and C–V measurements are carried out for understanding RTA temperature effects on charge storage behavior. 3-layer morphology and Sn content trends with RTA temperature are explained by the strongly temperature-dependent Sn segregation and diffusion processes. We show that the memory properties measured on Al/3-layer stack/p-Si/Al capacitors are controlled by SiGeSn-related trapping states (deep electronic levels) and low-ordering clusters for RTA at 325–450 °C, and by crystalline SiGeSn QDs for 520 and 530 °C RTA. Specific to the structures annealed at 520 and 530 °C is the formation of two kinds of crystalline SiGeSn QDs, i.e., QDs with low Sn content (2 at.%) that are positioned inside the floating gate, and QDs with high Sn content (up to 12.5 at.%) located at the interface of floating gate with adjacent HfO2 layers. The presence of Sn in the SiGe intermediate layer decreases the SiGe crystallization temperature and induces the easier crystallization of the diamond structure in comparison with 3-layer stacks with Ge-HfO2 intermediate layer. High frequency-independent memory windows of 3–4 V and stored electron densities of 1–2 × 1013 electrons/cm2 are achieved.

Urbach Energy and Open-Circuit Voltage Deficit for Mixed Anion-Cation Perovskite Solar Cells.

The Urbach energy indicating the width of the exponentially decaying sub-bandgap absorption tail is commonly used as the indicator of electronic quality of thin-film materials used as absorbers in solar cells. Urbach energies of hybrid inorganic-organic metal halide perovskites with various anion-cation compositions are measured by photothermal deflection spectroscopy. The variation in anion-cation composition has a substantial effect on the measured Urbach energy and hence the electronic quality of the perovskite. Depending upon the compositions, the Urbach energy varies from 18 to 65 meV for perovskite films with similar bandgap energies. For most of the perovskite compositions studied here including methylammonium (MA) + formamidinium (FA)-based Pb iodides, mixed Sn + Pb narrow-bandgap perovskites with low or intermediate Sn contents, and wide-bandgap FA + Cs- and I + Br-based perovskites, the correlation between the Urbach energy of the perovskite thin film and open-circuit voltage (VOC) deficit for corresponding solar cells shows a direct relationship with reduction of the Urbach energy occurring with a beneficial decrease in the VOC deficit. However, due to issues related to material quality, impurity phases and stability in laboratory ambient air, and unoptimized film processing techniques, the solar cells incorporating Cs-based inorganic and mixed Sn + Pb perovskites with a higher than optimum Sn content show a higher VOC deficit even though the corresponding films show a lower Urbach energy.

Microstructural characteristics and mechanical properties of additively manufactured Cu–10Sn alloys by laser powder bed fusion

Cu – 10 wt% Sn (Cu–10Sn) alloy specimens were additively manufactured by varying the laser powder bed fusion (LBPF) processing parameters, e.g., laser power (200–350 W) and laser scan speed (100–1400 mm/s) at a fixed hatch spacing (0.12 mm) and slice thickness (0.03 mm), to examine their effects on the density, melt pool structure, and microstructure. Microstructural characteristics of the most dense sample were examined using electron microscopy (SEM, TEM) and X-ray Diffraction. The grains in the top-most melt pool layer showed a fan-like structure, whereas all other areas showed small columnar structure aligned nearly parallel to the build direction due to multiple melt-solidification cycles. The high cooling rates associated with LPBF yielded a fine dendritic microstructure, which consisted of primary α1(Cu) dendrites and a mixture of α2(Cu) and δ (Cu41Sn11) phases in the interdendritic region. In addition, formation of thin laths (∼120 nm) was observed by TEM presumably due to diffusionless martensitic transformation from the high temperature β phase associated with fast cooling rates. The primary α1(Cu) dendrite and α2(Cu) within the interdendritic region contained low (∼6.6 wt%) and high (∼11.9 wt%) Sn concentration, respectively. Mechanical properties in tension of the dense Cu–10Sn alloy was measured in as-built condition, i.e., σUTS = 564 MPa, σY = 387 MPa, El = 26%; these are significantly superior to the properties determined in previous LPBF investigations and as-cast Cu–10Sn alloy, most likely due to contributions from Hall-Petch and dislocation strengthening mechanisms. Solidification path in LPBF fabricated Cu–10Sn alloy was also revealed from an extensive TEM investigation.

Cathodoluminescence Study of m‐Plane α‐Ga2O3 Grown by Mist Chemical Vapor Deposition

The cathodoluminescence (CL) properties of m‐plane α‐Ga2O3 grown by mist chemical vapor deposition are investigated. The m‐plane α‐Ga2O3 is found to have two types of characteristic luminescence bands: blue luminescence (BL) band (centered at 2.8 eV) and UV luminescence (UVL) band (centered at 3.7 eV). To characterize these bands, the Sn concentration and temperature dependences of the CL spectra are investigated using samples with varying Sn concentrations from 1 × 1017 to 1 × 1019 cm−3. The Sn concentration‐dependent CL spectra show that the luminescence from the UVL band is dominant in the low Sn concentration region, while that from the BL band is dominant in the high Sn concentration region. The temperature‐dependent CL spectra indicate that the peak intensity of the UVL band depending on temperature is larger than that of the BL band. The activation energies in the UVL band of the undoped and lightly Sn‐doped samples are determined as 110 meV. In addition, the parameters of the Huang–Rhys factor in the UVL band are obtained as 28.6 and 18.8, respectively. These results strongly suggest that the UVL band is derived from self‐trapped excitons, which is the recombination of free electrons and self‐trapped holes.

Evolution of Microstructure and Properties of an Ultrahigh Strength Cu-Ni-Sn Alloy with Low Sn Content During the Multi-Stage Thermomechanical Treatment

Evolution of Microstructure and Properties of an Ultrahigh Strength Cu-Ni-Sn Alloy with Low Sn Content During the Multi-Stage Thermomechanical Treatment

Evolution of Microstructure and Properties of an Ultrahigh Strength Cu-Ni-Sn Alloy with Low Sn Content During the Multi-Stage Thermomechanical Treatment

Evolution of Microstructure and Properties of an Ultrahigh Strength Cu-Ni-Sn Alloy with Low Sn Content During the Multi-Stage Thermomechanical Treatment