Addition Of Ge Research Articles

Exploring grain size and composition effects on the functional properties of BaGexTi1-xO3 ceramics

This study investigates BaGexTi1-xO3 ceramics with varying compositions (x = 0.010, 0.018, 0.100) produced by solid-state reaction, exploring the impact of composition and sintering temperatures (1150 °C, 1200 °C, 1300 °C) on functional characteristics (low-field dielectric, tunability, ferroelectric switching). Increasing Ge amount and sintering temperatures enhances sinterability of BaGexTi1-xO3 to almost complete densification. Room temperature permittivity ranges from 1000 to 2000, with dielectric losses below 10%. For small Ge additions, the dielectric behavior and phase transitions mirror BaTiO3 ceramics. Increasing Ge addition results in a slight increase of the Curie temperature. Dielectric relaxation mechanisms involve two activation energy ranges related to oxygen vacancies and ionic conduction. Ceramics with larger grain sizes exhibit well-defined ferroelectric P(E) loops, while fine-grained ones contain extrinsic contributions. The highest tunability performances are found for the lowest Ge additions, sintered at 1150 °C, which are able to withstand the application of the highest dc field.

Facile synthesis of GexSiO(1-x) alloys as a superior anode enables high-energy lithium-ion batteries

The large-scale development of low-cost silicon monoxide (SiO) anode is limited due to its low initial Coulombic efficiency (ICE) and poor cycle stability. Herein, the GexSiO(1-x) (0<x<1) composite anode has been facile synthesized by introducing germanium (Ge) atoms disrupted the structure of SiO matrix, which exhibits superior lithium storage performance. In particular, the optimized Ge0.5SiO0.5 electrode with nanoscale dispersion shows a high ICE of 80.2 % and a reversible capacity of 673.9 mAh g−1 after 100 cycles. To evaluate the effect of the Ge addition on the electrochemical properties, the lithium storage behaviors and structural evolution of the GexSiO(1-x) electrodes are investigated systematically. The in-situ electrochemical dilatometry reveals that the Ge0.5SiO0.5 electrode displays a better reversible thickness variation during cycling process. Density functional theory (DFT) calculation demonstrates that the SiGe domain can accommodate the volume expansion of Si and Ge domains. Moreover, the relationships between the electrochemical performance and morphology evolution demonstrate that the disordered structure and nanoscale distribution of Ge0.5SiO0.5 electrodes are the main reasons for improving ICE and cycle stability. This work provides a commercially available synthetic route for the design of advanced anode materials for large-scale energy storage applications.

Influence of germanium concentration on the microstructure and optical transparency of terbium gallium garnet ceramics

AbstractIn recent years, transparent terbium gallium garnet (TGG) ceramics have garnered significant interest for their application in high‐power Faraday isolators. However, challenges in achieving high transparency have led researchers to explore the addition of various sintering aids as a key strategy to enhance the optical quality of TGG ceramics. Through this work, the effect of germanium (Ge) addition on the microstructure and optical transparency of TGG magneto‐optical ceramics was investigated. TGG powders were synthesized by the co‐precipitation method, and the source Ge was Ge ethoxide added through a ball‐milling step. Transparent TGG ceramics were prepared by air pre‐sintering combined with hot isostatic pressing post‐treatment and subsequent annealing. The ceramics containing 200 ppm Ge exhibit optimal transmittance of 81.3% at 1064 nm (a value of theoretical transmittance), the Verdet constant was −133.0 rad·T−1·m−1 at 633 nm. When the addition of Ge reaches 600 ppm, a secondary phase can be observed on the surface of ceramic. Subsequently, TGG ceramics prepared from 1425°C to 1500°C with 200 ppm of Ge were analyzed, which revealed that the optimal pre‐sintering temperature is 1450°C.

Atomistic Compositional Details and Their Importance for Spin Qubits in Isotope-Purified Silicon Quantum Wells.

Understanding crystal characteristics down to the atomistic level increasingly emerges as a crucial insight for creating solid state platforms for qubits with reproducible and homogeneous properties. Here, isotope concentration depth profiles in a SiGe/28Si/SiGe heterostructure are analyzed with atom probe tomography (APT) and time-of-flight secondary-ion mass spectrometry down to their respective limits of isotope concentrations and depth resolution. Spin-echo dephasing times and valley energy splittings EVS around have been observed for single spin qubits in this quantum well (QW) heterostructure, pointing toward the suppression of qubit decoherence through hyperfine interaction with crystal host nuclear spins or via scattering between valley states. The concentration of nuclear spin-carrying 29Si is 50 ± 20ppm in the 28Si QW. The resolution limits of APT allow to uncover that both the SiGe/28Si and the 28Si/SiGe interfaces of the QW are shaped by epitaxial growth front segregation signatures on a few monolayer scale. A subsequent thermal treatment, representative of the thermal budget experienced by the heterostructure during qubit device processing, broadens the top SiGe/28Si QW interface by about two monolayers, while the width of the bottom 28Si/SiGe interface remains unchanged. Using a tight-binding model including SiGe alloy disorder, these experimental results suggest that the combination of the slightly thermally broadened top interface and of a minimal Ge concentration of % in the QW, resulting from segregation, is instrumental for the observed large . Minimal Ge additions <1%, which get more likely in thin QWs, will hence support high EVS without compromising coherence times. At the same time, taking thermal treatments during device processing as well as the occurrence of crystal growth characteristics into account seems important for the design of reproducible qubitproperties.

A preliminary investigation into the potential of Ge-enhanced Cu2SnS3 (CTS) thin-film applications for water-splitting photoelectrodes

This study explores the potential of Ge-enhanced Cu2SnS3 (CTS) thin-films as photoelectrode materials for water splitting grown through a simple sulfurization process. The addition of Ge to CTS enabled tuning the bandgap and improved the photocurrent density. Films sulfurized at 520 °C exhibit enhanced grain size and reduced grain boundaries, which contribute to increased carrier transport efficiency. By optimizing Ge content and sulfurization conditions, the Cu2(Sn1−x ,Ge x )S3 films demonstrate promising capabilities for efficient green hydrogen production. This work lays the groundwork for developing advanced photoelectrodes and highlights the need for further refinement to maximize performance for practical applications.

The Effect of Germanium Additions on the Mechanical Properties of Zn-Mg-Al Alloys

In this investigation, 0.19 wt.%–1.8 wt.% of Ge was introduced into a ternary Zn-Mg-Al alloy. The introduction of Ge had a significant impact on the microstructure, leading to the formation of Mg2Ge. The area fraction of the eutectic phase diminished with increasing Ge additions. Small-scale test techniques were utilised to evaluate the mechanical properties due to the changes in microstructure. Zn-Mg-Al alloys were found to be inherently harder compared to standard hot-dip Zn-containing 0.2 wt.% Al. The hardness and strength of the Zn-Mg-Al alloys decreased with the increase in Ge additions.

Design and fabrication of PPTA-braid-reinforced PFA/GE hollow fiber composite membranes

Due to the effects of the rapid development of modern society and fresh water resource pollution, water shortage has further accelerated, which is becoming a very urgent problem. Herein, the poly (p-phenylene terephthalamide)-(PPTA-) braid-reinforced (PBR) poly(tetrafluoroethylene-co-perfluoropropylvinylether)/graphene (PFA/GE) hollow fiber composite membranes (HFCMs) were prepared by dipping coating-thermal sintering coupling technique with a green process. GE is an emerging type of two-dimensional functional nanoparticle with a tunable passageway for oil molecules. The influences of the GE concentration in the casting solution on the structure and performance of the PBR−PFA/GE HFCMs were investigated. The results showed that the addition of GE produced a finger-like pore structure suitable for oil channels. Meanwhile, the roughness and contact angle of the composite membrane increased accordingly, and the water contact angle increased from 115° to 120°. The permeation fluxes of kerosene also increased obviously with the increase of GE contents, and the maximum flux of M-3 reached as high as 217.66 L·m−2·h−1. The application of the lubricating oil flux test under working conditions of 60–150 °C has demonstrated the high-temperature oil permeability resistance of the composite membrane. Even after long-term use, its separation efficiency for water-in-oil emulsions still remains above 99.5 %. In addition, the membrane separation-efficiency both up to 99.9 % for activated carbon and silica dioxide (SiO2) in kerosene. Overall, the PBR-PFA/GE HFCMs with excellent lipophilicity presented great potential for oily wastewater treatment at high temperatures.

Stress-induced intersecting stacking faults and shear antiphase boundary in Zr5Ge4 second phase precipitate embedded in Ge-modified Zircaloy-4

Secondary phase precipitates are vital to control mechanical, corrosion and irradiation response of the multiphase alloy systems. This work reports the mechanical response of an ordered complex intermetallic Zr5Ge4 precipitate during hot working of the experimental Zircaloy-4 modified with dilute Ge addition. Atomic scale insight is provided into the formation mechanism of straight and circular stacking faults and shear antiphase boundary in Zr5Ge4 precipitate. Two types of stacking faults, having displacement vectors 1/3[100] and 1/3[110] with small components along the c-axis, come across and form a distinct region on the (001) surface composed of a zigzag atomic arrangement different from the parent crystal. Besides this, a shear antiphase boundary along the Zr5Ge4/fcc-Zr interface is analysed and concomitant generation of nanotwins is evidenced by the streaking effect in the associated fast Fourier transform (FFT) pattern. By analysing the distortion and stacking faults in the surrounding fcc-Zr phase, comments are made on the role of external stresses in generating the aforementioned planar defects. The relative activity of two types of displacement vectors observed in Zr5Ge4 precipitate is discussed on the basis of the nature of the atomic bond.

The Effect of Ge Doping on α-Ag2S’s Thermoelectric and Mechanical Properties

Thermoelectric materials are capable of generating electrical energy in response to a temperature gradient. Non-renewable energy resources are depleting, so the development of renewable energy sources that are environmentally sustainable is essential. One potential application of these materials as an alternative energy source is in wearable electronics. Thermoelectric materials are used in common electrical devices, as well as by the military, in healthcare, and in space. As a ductile N-type semiconducting material, silver sulfide is one of the most promising materials in terms of thermoelectric potential. The properties of Ag2S can be improved by choosing the appropriate dopants. This study investigates the methods by which the thermoelectric, mechanical, and hardness properties of Ag2S are improved via Ge doping. The addition of Ge increases the Seebeck coefficient to a maximum of −87 μV·K−1 from −1051 μV·K−1 to P-type, bringing it closer to transitioning. In order to work, a thermoelectric generator requires both N- and P-type materials. By applying homojunctions made from similar materials, internal stresses caused by the varying thermal expansion rates of different materials are reduced. In order to demonstrate Ge integration, scanning electron microscopy and X-ray diffraction were applied to the sample microstructure. In addition, supplementation was used to increase the ductility and malleability of materials to make them suitable for power generation in wearable electronics. These materials showed significant power factor values according to room-temperature measurements. This proves that materials capable of generating usable voltage lie in the recommended ambient temperature range for the user’s body, thus rendering them potential candidates for wearable electronics.

Narrow bandpass filter with ultra-wide stopband in a hybrid metal-optical Tamm state structure

Narrow bandpass filters (NBPF) play an important role in quantum communications, optical biometrics and other fields. However, traditional narrow bandpass filters have limited stopband capabilities. Here, an ultrawide stopband narrow bandpass filter is realized by combining a metal layer with a distributed Bragg reflector (DBR) structure to simultaneously excite the upper and lower Tamm plasma polarization (TP) modes. Numerical simulations show that the transmittance of the filter exceeds 94 % at a wavelength of 1.55 μm with a full width at half maximum (FWHM) of 8 nm. In addition, the addition of metal layer Ge reduces the electric field intensity of the lower DBR structure, effectively reducing the side peak, making the filter stopband range reach 1 μm–20 μm, which is 32 times that of traditional NBPF. Our research results provide a method to obtain narrow-band optical signals from ultra-broad and strong background noise, which facilitates the field of quantum communication.

Ultra-high-purity Mg-Ge anodes enable a long-lasting, high energy-density Mg-air battery

The primary Mg-air battery shows extraordinary theoretical energy density to satisfy the requirements that traditional rechargeable batteries cannot reach. However, the battery has failed to live to its potential due to its low operating discharge voltage, parasitical anodic hydrogen reaction and irreversible corrosion. To address these issues, we devised a process to generate ultra-high-purity (UHP) Mg-Ge anodes for Mg-air batteries. The Ge addition enhances the anodic reaction activity and suppresses the anodic hydrogen evolution reaction (AHER). Hence, the fabricated UHP Mg-0.5Ge anode exhibited a remarkably high discharge voltage of 1.69 V (0.5 mA cm−2) coupled with a high energy density of 2272 mWh g−1 (20 mA cm−2). These values are higher than all the reported Mg-based anodes in the literature. Furthermore, the minimal impurity content and the development of a Ge-bearing surface layer contribute to the UHP Mg-0.5Ge anodes achieving a 95% intermittent discharge efficiency, which is 3.5 times higher than that of the commonly employed AZ31 anode. The outstanding properties of the fabricated UHP Mg-Ge anode set the stage for advancing the next generation of Mg-air batteries.

Effect of Ge Contents on Oxidation Resistance of Ni‐15Cr‐5Al Alloy at 1000°C

A Ni‐15Cr‐5Al‐6Ge alloy was prepared using powder metallurgy technology. The effect of Ge on the oxidation resistance of Ni‐Cr‐Al alloy at 1000°C was investigated. The results indicate that the addition of Ge reduces the oxidation rate of the alloy interface in the range of 0 to 6 wt.% Ge. When the Ge content reaches 6 wt.%, a continuous and dense oxide film forms on the surface of the matrix, imparting the alloy with the best oxidation resistance. The addition of Ge improves the selective oxidation of Al and inhibits the diffusion rate of Ni and Cr elements to the alloy surface, resulting in the formation of a single, uniform Al2O3 oxide film on the alloy surface with a thickness of approximately 1.45 micrometers. An appropriate amount of Ge (6 wt.%) reduces surface defects, while an excessive amount of Ge (8 wt.%) increases surface defects, thereby adversely affecting the oxidation resistance of the alloy.

Electrochemical corrosion behaviour and corrosion mechanism of Sn-9Zn-xGe solder alloys in NaCl solution

The electrochemical corrosion behaviour and corrosion mechanism of Sn-9Zn-xGe alloy in 3.5 wt.% NaCl solution was investigated using electrochemical techniques combined with surface characterization techniques. The results showed that the alloy corrosion was mainly affected by the rupture of passivation film and Cl- migration along grain boundaries. Trace Germanium (Ge) addition refined the microstructure and improved the corrosion potential of the alloy. Solder alloys containing 0.6 wt.% Ge formed a uniform and dense passivation film on the corrosion surfaces, which reduced the corrosion rate and increased the corrosion resistance.

Improved CZTSe solar cell efficiency via silver and germanium alloying

In this study, we report systematic investigation of the effects of Ag and Ge alloying on properties of CZTSe layers, as well as, on the performance of solar cells fabricated using these films. In this context, Ag-Ge doped CZTSe layers were produced by selenization of Cu/Sn/Zn/Cu/(Ag,Ge)/Se precursor stack structures using rapid thermal processing. All precursor stacks and the Ag-Ge doped CZTSe films obtained after selenization exhibited (Cu + Ag)-poor and Zn-rich chemical composition. XRD studies demonstrated pure kesterite phase for all reacted films. Raman spectra confirmed this finding. Cross-sectional SEMs showed large grain structure, which resulted from Ag-Se and Ge-Se liquid phase formation that assisted crystal growth during high temperature annealing. While a slight Ag-front-gradient was achieved in Ag-doped CZTSe film, the Ag gradient disappeared with incorporation of Ge into the lattice. Addition of Ge formed a gradient within the material such that near-contact region was more Ge-rich. Solar cells fabricated using films with various compositions demonstrated that double doping CZTSe with both Ag and Ge improved the device efficiency from about 5 % to over 8 %.

Effect of Ag and Ge on the precipitation behavior and resultant properties of AA6061 alloys

This study investigated the effects of Ag and Ge on the precipitation behavior and resultant properties of AA6061 alloys using hardness measurements, electrical conductivity tests, transmission electron microscopy (TEM), and atom probe tomography (APT). Trace addition of Ge can increase the electrical conductivity and thermal stability, but slightly deteriorates the hardness during the early- and peak-aging stages. Trace addition of Ag can enhance the hardness during aging, especially in the over-aging stage, but it deteriorates the electrical conductivity. For the Ag-added alloys, the Ag atoms provide more nucleation sites and are substantially incorporated into the clusters, suggesting the formation of various types of precipitates with increasing aging time. During the peak- and over-aging stages, the Ag atoms not only segregate but also incorporate into the precipitates, resulting in the disordering of the precipitates and suppression of the coarsening of the precipitates. For the Ge-added alloys, the formation and evolution of the clusters are suppressed by Ge addition, owing to the high binding energy between the Ge and Mg atoms. With the aging time increasing, the Ge atoms are incorporated into the precipitates and suppress the ordering process of the precipitates, resulting in better thermal stability of the Ge-added alloys in the over-aging stage. The addition of both Ag and Ge shows potential for elevated temperature component applications.

Thermoelectric properties of binary Mg2Sn and ternary Mg2Sn1−xYx (Y = Si, Ge) with the addition of Cu2S

Doped and undoped ternary and binary Mg2Sn solid solutions were fabricated using high-energy ball milling followed by hot pressing according to the nominal Mg2Sn1−xYx (X = 0, 0.25 and Y= Si, Ge) composition with the addition of 20 at% of Cu2S. The effects of Cu2S addition on the thermal conductivity, Seebeck coefficient and electrical conductivity were investigated in the temperature range of 300–800 K. It was found that the Cu2S addition increased both the electrical conductivity and Seebeck coefficient simultaneously, which is unusual in thermoelectricity, leading to enhancement of the power factors. Additionally, the addition of Cu2S significantly decreases the thermal conductivity. It was also observed that the ternary compositions (i.e. compositions containing Si, Ge) results in a high power factor as a result of the combined optimized Seebeck coefficient and electrical conductivity. This is as a result of phase separations into SnS and Mg3Sb2 phases, which are enhanced by the addition of Si and Ge. Overall, the ZT values significantly improved to 1.35 at 700 K and 1.3 at 750 K for Si and Ge ternary samples, respectively.

Nanocomposites of soluble soybean polysaccharides with grape skin anthocyanins and graphene oxide as an efficient halochromic smart packaging

In this study, an environmentally-friendly pH-responsive (halochromic) film was introduced based on the composite of soluble soybean polysaccharide (SP), grape skin anthocyanin extract (GE) and graphene oxide (GO) to monitor food freshness/spoilage in terms of smart packaging. GO was firstly synthesized and characterized; then, SP-based film containing 5 wt% GE and the optimum amount of GO (0.5 wt%) was fabricated through the solvent casting method and characterized in terms of physico-mechanical, thermal, microstructural, spectroscopic, release, pH sensitivity and colorimetric properties. Our results revealed that addition of GE into the SP matrix induced pH sensitivity to the film; however, it decreased the mechanical and thermal properties, and increased moisture content (MC) and water vapor permeability (WVP) of the film. The incorporation of GO into the film eliminated the GE-caused weaknesses and improved the mechanical and thermal properties, and also decreased the MC and WVP of the film. Moreover, the SP-GE-GO nanocomposite film represented a distinguishable color variation in response to TVB-N release and pH changes when used as the salmon fish packaging. Generally, the obtained results indicated that the SP-GE-GO film can be considered a promising candidate for halochromic smart food packaging.

Correlation between crystallite size, resistance to oxidation, and phase transformation of germanium-doped Fe3O4 nanocrystalline thin films by using a sputtering target of α-Fe2O3

We investigated the correlation between the crystallite size, resistance to oxidation, and phase transition of Ge-doped Fe3O4 nanocrystalline thin films. We prepared thin films on water-cooled glass substrates by radiofrequency sputtering with Ge-tipped α-Fe2O3 ceramic disks as targets. The addition of Ge caused a reductive phase transition from α-Fe2O3 with a corundum structure to Ge-doped Fe3O4 with an inverse spinel structure, resulting in a crystallite size of &amp;lt;10 nm. We annealed three samples with average sizes of 5, 8, and 10 nm by changing Ge addition concentrations at 673 K in air for up to 323 days until reaching near-thermal equilibrium. All samples maintained their magnetization at almost a constant value over long-term heat treatment. The results of Raman spectroscopy and optical transmittance spectroscopy suggest that there was a phase transition to Ge-doped γ-Fe2O3 at 5 nm, Ge-doped Fe3−δO4 with iron vacancies δ at 8 nm, and Ge-doped Fe3O4 at 10 nm. In other words, we retained Fe3O4 down to a relatively small crystallite size of 10 nm because of the improved oxidation resistance imparted by Ge doping.

Suppressing laves phase and overcoming magnetic properties tradeoff in nanostructured (Ce,La,Y)–Fe–B alloys via Ge substitution

Developing permanent magnets based on full high abundance rare-earth (RE) elements of Ce, La, and Y offers tremendous potential for the balanced utilization of RE resources, but the magnetic properties of these magnets are restricted due to the magnetic dilution caused by the existence of the paramagnetic REFe2 laves phase. Herein, the non-RE element Ge with high efficiency was introduced to enhance the magnetic performance of Ce-, La-, and Y-based RE–Fe–B nanocrystalline alloys, and the highest maximum energy product [(BH)max] of 65.6 kJ/m3 and an enhanced coercivity (Hcj) of 346 kA/m were achieved in the [(Ce0.8La0.2)0.5Y0.5]16Fe77.5B6Ge0.5 alloy. This improvement is attributed to the increased content of the hard magnetic RE2Fe14B phase with refined grain size, which is further confirmed by micromagnetic simulation. First-principles calculations and a microstructure analysis reveal that the laves phase is effectively suppressed by Ge addition due to the formation of the Ce5Ge3 phase with the lowest formation energy. This work clarifies the positive role of Ge in simultaneously enhancing the Hci and (BH)max of nanostructured (Ce,La,Y)–Fe–B alloys.

Effect of Ge addition on the clustering of naturally-aged Al–Mg–Si–Cu alloy

Ge addition effect on the delaying natural aging of Al–Mg–Si–Cu alloy was investigated. Natural aging kinetic and cluster size was suppressed by the Ge addition. Using atom probe tomography, it was found that Ge refines cluster evolution by disturbing Mg-enrichment of Si–Si cluster as well as enhancing vacancy trapping. Segregation of Ge at the interface of cluster was also regarded as potential barrier to growth of the clusters.