Mechanisms of InGaAlAs solid solution decomposition stimulated by InAs quantum dots

Mechanisms of InGaAlAs solid solution decomposition stimulated by a purposely deposited layer of InAs quantum dots are studied. Decomposition of the solid solution results in an increase in the effective quantum dot size and the shift of the photoluminescence line to as far as 1.3 μm. When aluminum atoms are added to the solid solution, the effect of In atom “conservation” within the dots is observed, which also causes an increase in the effective dot size. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 34, No. 3, 2000, pp. 330–333. Original Russian Text Copyright ? 2000 by Tsatsul’nikov, Volovik, Bedarev, Zhukov, Kovsh, Ledentsov, Maksimov, Maleev, Musikhin, Ustinov, Bert, Kop’ev, Bimberg, Alferov.     

The Effect of Additives on Amorphous Calcium Carbonate (ACC): Janus Behavior in Solution and the Solid State

Amorphous calcium carbonate (ACC) is an important intermediate in the formation of crystalline CaCO₃ biominerals, where its crystallization is controlled using soluble additives. However, although this transformation often occurs in the solid state, experiments mainly focus on the effect of additives on ACC crystallization in solution. This paper addresses this issue and compares the crystallization, in solution and in the solid state, of ACC precipitated in the presence of a range of additives. Surprisingly, these results show that some additives exhibit a Janus behavior, where they retard crystallization in solution, yet accelerate it in the solid state. This is observed for all of the larger molecules examined, while the small molecules retard crystallization in both solution and the solid state.     

波纹管的失效分析

通过对波纹管故障件的断口检查和制造工艺分析 ,证实了波纹管的失效是由于采用盐炉固溶处理工艺 ,零件表面产生大量氧化微裂纹缺陷 ,使零件疲劳操作损伤所致。改用真空固溶处理工艺后 ,消除了缺陷 ,波纹管的工作寿命由原来的不足 35h提高到 2 0 0h以上。     

Solid solution InxGa1−x AsySbzP1−y−z : A new material for infrared optoelectronics. I. Thermodynamic analysis of the conditions for obtaining solid solutions, isoperiodic to InAs and GaSb substrates, by liquid-phase epitaxy

The diagrams of melt-solid solution (fusibility curves) and solid solution (I)-solid solution (II) (surfaces of spinodal decomposition of solid solutions) phase equilibria in the five-component system In-Ga-As-Sb-P (the solid solutions are isoperiodic to the GaSb and InAs substrates) are calculated. The concentration ranges of the isovalent substitution solid solutions In_xGa_1−x As_ySb_zP_1−y−z , which are accessible for synthesis by liquid-phase epitaxy, are calculated. Fiz. Tekh. Poluprovodn. 31, 410–415 (April 1997)     

Long-wavelength emission in structures with quantum dots formed in the stimulated decomposition of a solid solution at strained islands

When an array of strained InAs nanoislands formed on a GaAs surface is overgrown by a thin (1–10 nm) layer of an indium-containing solid solution, stimulated decomposition of the solid solution is observed. This process causes the formation of zones of elevated indium concentration in the vicinity of the nanoislands. The volume of newly formed InAs quantum dots increases as a result of this phenomenon, producing a substantial long-wavelength shift of the photoluminescence line. This effect is enhanced by lowering the substrate temperature, and it depends weakly on the average width of the band gap of the solid solution. The indicated approach has been used successfully in achieving room-temperature emission at a wavelength of 1.3 μm. Fiz. Tekh. Poluprovodn. 33, 990–995 (August 1999)     

Lattice mismatch and the nature of dissolution in the LPE of Pb-Salt compounds

It is shown experimentally that lattice matching is important in determining the nature of the solid/solution interface behavior during controlled meltback near saturation conditions. We define the lattice matching between a crystalline substrate and a solution via the solid in equilibrium with the solution and in a similar way lattice mismatch conditions can be defined as well. We found that a flat interface is preserved during meltback and regrowth if the solution is lattice matched to the substrate even when they are of different chemical potentials. Meltback and regrowth under matched conditions has been used to form graded-gap heterostructures with flat interfaces. We suggest using undersaturated lattice matched solutions whenever an in situ removal of the top part of a substrate is needed prior to epitaxial growth.     

Liquid–Solid Triboelectric Probes for Real-Time Monitoring of Sucrose Fluid Status

Triboelectric probes have rapidly developed as an efficient tool for understanding contact electrification at liquid–solid interfaces. However, the liquid–solid electrification process is susceptible to interference from chemical components in mixed solutions, severely limiting the potential applications of triboelectric probes in various liquid environments. This study for the first time reports a triboelectric probe capable of sucrose solution concentration sensing, finding that the dissolution of sucrose destroys the hydrogen bond network between water molecules and forms sucrose–water hydrogen bonds, which alters the fluid mechanics characteristics of the solution and enhances its conductivity, thereby reducing the droplet size and causing an ion charge shielding effect that significantly affects the electron transfer in liquid–solid contact electrification. Owing to the feedback of the triboelectric probe on the sucrose concentration gradient-type sensing electrical signals, efficient sensing of sucrose solution was achieved (sensitivity of −0.0038%⁻¹, response time of 90 ms). The triboelectric probe is also used as a wireless smart terminal to enable real-time detection of sucrose solution. This work contributes to the understanding of the structure–function relationship between micro hydrogen bonding and macro performance, and provides a promising solution for building sustainable intelligent sensors.     

Ion-Bombardment-Induced Decomposition of Nonequilibrium Solid Solution and the Formation of Periodic Structures

A model of forming periodic structures induced on a solid surface by a uniform ion flow (at high implant concentrations) is put forward. It is shown that these periodic structures are a result of the decomposition of the resulting solid solution.     

Phonon Scattering and Thermal Conductivity in p‐Type Nanostructured PbTe‐BaTe Bulk Thermoelectric Materials

Transmission electron microscopy studies show that a PbTe‐BaTe bulk thermoelectric system represents the coexistence of solid solution and nanoscale BaTe precipitates. The observed significant reduction in the thermal conductivity is attributed to the enhanced phonon scattering by the combination of substitutional point defects in the solid solution and the presence of high spatial density of nanoscale precipitates. In order to differentiate the role of nanoscale precipitates and point defects in reducing lattice thermal conductivity, a modified Callaway model is proposed, which highlights the contribution of point defect scattering due to solid solution in addition to that of other relevant microstructural constituents. Calculations indicate that in addition to a 60% reduction in lattice thermal conductivity by nanostructures, point defects are responsible for about 20% more reduction and the remaining reduction is contributed by the collective of dislocation and strain scattering. These results underscore the need for tailoring integrated length‐scales for enhanced heat‐carrying phonon scattering in high performance thermoelectrics.     

Ti-6Al-4Cr（Mo）合金热处理显微组织的研究

本文采用扫描电镜与透射电镜分析研究了Ti-6Al-4Cr和Ti-6Al-4Mo合金固溶和时效过程中显微组织的变化。结果表明：Ti-6Al-4Cr和Ti-6Al-4Mo合金经过相似的两相区固溶处理后,组织差别较大;两种合金经过β相区固溶后再时效,形成典型的魏氏组织,且硬度值较两相区处理的样品有很大提高;两种合金在相同热处理制度下,硬度值变化趋势相似,但前者的硬度值明显大于后者;Ti-6Al-4Cr合金在各种热处理条件下都有富Cr的固溶体区产生,经过1000℃/45min/空冷＋600℃/2h/空冷处理后,有Laves相和界面相析出。     

Inter-triplet spin–spin interaction effects on inter-conversion between different spin states in intermediate triplet–triplet pairs towards singlet fission

This article reports the experimental studies on the effects of inter-triplet spin interaction on singlet fission by using magnetic field effects of photoluminescence (MFE_PL) based on tetracene. The MFE_PL are compared for three different morphological states based on polycrystalline solid powder, amorphous solid film, and liquid solution. It is observed that the polycrystalline solid powder gives stronger MFE_PL than that of amorphous solid film, while the liquid solution exhibits no detectable MFE_PL. In essence, the MFE_PL are determined by the inter-conversion between different spin states initiated by inter-triplet spin interaction through spin mixing in intermediate triplet–triplet pairs towards the singlet fission. The different MFE_PL amplitudes suggest that the polycrystalline solid powder possesses an enhanced inter-triplet spin interaction in intermediate triplet–triplet pairs as compared to amorphous solid film. As a result, the enhanced inter-triplet spin interaction can cause a larger inter-conversion between different spin states in intermediate triplet–triplet pairs and consequently increases the singlet fission within polycrystalline structures. The absorption spectral characteristics and X-ray diffraction data confirm that the polycrystalline solid powder can indeed exhibits stronger intermolecular electronic interaction relative to amorphous solid film. Here, the stronger intermolecular electronic interaction provides an evidence for the enhanced inter-triplet spin interaction occurring within polycrystalline structures in the solid powder. Our experimental results indicate that increasing the inter-triplet spin interaction can boost the inter-conversion between different spin states in intermediate triplet–triplet pairs and consequently facilitates the singlet fission.     

Zinc Gallogermanate Solid Solution: A Novel Photocatalyst for Efficiently Converting CO2 into Solar Fuels

As global energy demand continues to grow, the need to find a carbon‐neutral and sustainable energy source for future generations has become imperative. An especially attractive solution is to store solar energy in the form of chemical fuel via artificial photosynthesis to convert carbon dioxide into hydrocarbons. An artificial photosynthesis system is introduced based on a zinc gallogermanate solid solution photocatalyst that can convert the carbon dioxide and water into methane. The solid solution of cubic spinel ZnGa₂O₄ and pseudocubic inverse spinel Zn₂GeO₄ is successfully synthesized by hydrothermal ion exchange reaction. Introducing Zn₂GeO₄ into ZnGa₂O₄ can effectively narrow band gap by the upshift of valence band edge from the enhanced p‐d (O2p‐Zn3d) repulsion effect by incorporating s and p orbitals of Ge, and the downshift of conduction band edge by introducing the low‐energy s orbital of Ge. The zinc gallogermanate solid solution has a light‐hole effective mass, which is beneficial to improving hole mobility, and thus enhancing the ability of photocatalyst in water oxidation to provide protons for CO₂ photoreduction. As a result of band gap narrowing and high hole mobility, the zinc gallogermanate solid solution exhibits high activity in converting CO₂ and H₂O into CH₄ and O₂.     

固溶温度对铝基复合材料组织结构和力学性能影响

以2009/SiC/15p颗粒增强铝基复合材料锻件作为研究对象,选取不同的固溶温度进行固溶时效处理,对试样的显微组织结构及力学性能进行观察分析。结果表明:在固溶时效状态下,2009/SiC/15p复合材料主要由Al、SiC(6H,3C)相和少量的Al2Cu、Mg2Si、Al7Cu2Fe第二相构成,其中Al2Cu能够在高温下发生溶解,而Al7Cu2Fe难以溶解。随着固溶温度的升高,材料的室温拉伸性能和轴向疲劳性能均明显提高,一方面高温促进Al2Cu相中的Cu溶入基体,引起晶格畸变,形成固溶强化,提高了材料的强度;另一方面高温增加了合金元素的固溶度,提高了材料的塑性。     

Spray pyrolysis deposition of Cu–Zn–In–S solid-solution thin films with tunable compositions and band gaps

Cu–Zn–In–S solid solution thin films with tunable compositions and band gaps were deposited on glass substrates using a chemical spray pyrolysis approach. XRD results reveal the cubic-structured Cu–Zn–In–S films without detectable impurities. The successive shift of XRD patterns toward high-angle side of ZnS with increasing ZnS molar fraction in products proves a formation of Cu–Zn–In–S solid solutions. SEM images and EDAX analyses demonstrate homogeneous surface morphologies and adjustable compositions of Cu–Zn–In–S films, which results in film band gaps broadly tunable from 1.54 eV to 3.61 eV. These sprayed Cu–Zn–In–S solid solution thin films may find potential uses in photovoltaics and photocatalysis.     

Pseudobinary Solid‐Solution: An Alternative Way for the Bandgap Engineering of Semiconductor Nanowires in the Case of GaP–ZnSe

Bandgap engineering of semiconductor nanostructures is of significant importance either for the optical property tailoring or for the integration of functional optoelectronic devices. Here, an efficient way to control the bandgap and emission wavelength is reported for a binary compound semiconductor through alloying with another binary compound. Taking GaP‐ZnSe system as an example, the bandgap of quaternary GaP‐ZnSe solid‐solution nano­wires can be selectively tailored in the range of 1.95–2.2 eV by controlling the solubility of ZnSe dopants in GaP host. High‐resolution transmission electron microscopy measurement and chemical analyses using an X‐ray energy dispersive spectrometer (EDS) demonstrate the solid‐solution feature of GaP‐ZnSe semiconductor alloy, while X‐ray photoelectron spectroscopy (XPS) characterization verifies the formation of some new chemical bonds corresponding to Zn‐P and Ga‐S bonds in GaP‐ZnSe nanowires. The strategy to tailor the optoelectronic property of semiconductor nanostructures through the solid‐solution of two different binary compounds represents a general routine to the property modification of all pseudobinary systems and will open more opportunity for their applications in electronics, optics and optoelectronics.     

钛酸锌微波介电陶瓷的改性研究现状

对钛酸锌介电陶瓷的改性研究进行了综述,分析了形成固溶体、生成新的化合物和添加助熔剂对钛酸锌陶瓷的烧结性、相结构和微波介电性能的影响。结果表明,形成无限固溶体的陶瓷主晶相为六方相,微波介电性能优良,但烧结温度偏高;添加助熔剂虽改善了烧结性,但主晶相与加入量及烧结温度有关,微波介电性能随主晶相变化。据此提出了复合改性的设想。     

矩形管中对空间立体角积分的计算方法

根据任意闭合曲面对曲面外任一点所张立体角等于零这一特点，我们提出了积分面转换的计算方法，即把对矩形管侧面的积分转变为对矩形管横截面的积分，同时，在轴向采用线性插值函数的条件下，将矩形管横截面的积分表示成解析形式，从而实现了矩形管侧面对空间任一点所张立体角积分的完全解析表示。     

H13钢表面激光选区熔覆Ni-Al金属间化合物涂层的组织与性能

通过控制Ni 基自熔性合金粉末中Al 的含量,在H13 热作模具钢表面分别原位制备了Ni3Al和NiAl 金属间化合物复合熔覆涂层。借助光学显微镜和X 射线衍射仪对不同熔覆涂层的化学组成和物相结构进行了分析。结果表明,四种不同Al 含量的熔覆层均显现出平整致密、无明显缺陷的宏观特征。随着Al 含量的增加,熔覆层显微形貌呈现出底部枝晶区域增加及枝晶逐渐粗化,甚至出现胞状晶的现象。熔覆层在未加入Al 时,其主要物相为Ni3Fe 及（Ni, Cr）固溶体。随着Al 含量的增加,主要物相则由最初的Ni3Al 金属间化合物、（Ni, Cr）固溶体到Ni3Al、NiAl 金属间化合物和（Fe,Cr）固溶体,再到最终Al 含量达到13.9%时的NiAl 金属间化合物和（Fe,Cr）固溶体。同时,Al 含量的提高使得涂层中杂质相减少。熔覆层摩擦系数均低于基体,最高显微硬度为基体的3.5 倍,耐磨性较基体提高了5.8 倍。     

Comparative photoelectric characteristics of nanostructured Pb1 − x Sn x Se films obtained by the codeposition and layer-by-layer deposition of PbSe and SnSe

Comparative analysis of the photoelectric characteristics of films of the Pb_0.975Sn_0.025Se solid solution obtained by the hydrochemical codeposition of PbSe and SnSe and the Pb_0.902Sn_0.098Se solid solution obtained by the layer-by-layer hydrochemical deposition of individual metal selenides (SnSe-PbSe-SnSe-PbSe) with their subsequent heat treatment on air at 523–700 K is performed. It is shown that the films synthesized by layer-by-layer deposition have advantages in terms of their photoelectric characteristics compared with films obtained by codeposition.     

Solid Additive Delicately Controls Morphology Formation and Enables High-Performance in Organic Solar Cells

Volatile solid additives are an effective strategy for optimizing morphology and improving the power conversion efficiencies (PCEs) of organic solar cells (OSCs). Much research has been conducted to understand the role of solid additives in active layer morphology. However, it is crucial to delve deeper and understand how solid additives affect the entire morphology evolution process, from the solution state to the film state and the thermal annealing stage, which remains unclear. Herein, the use of a highly crystalline solid additive, phenoxathiin (Ph), in D18-Cl:N3-based OSCs and study its impact on morphology formation and photovoltaic performance is presented. Owing to its good miscibility with the acceptor N3, Ph additive can not only extend the time for the active layer to form from the solution state to the film state, but also provide sufficient time for acceptor aggregation. After thermal annealing, Ph solid additive volatilizes better aligned the N3 molecules and formed a favorable hybrid morphology. Consequently, the D18-Cl:N3–based OSC exhibited an outstanding PCE of 18.47%, with an enhanced short-circuit current of 27.50 mA cm⁻² and a fill factor of 77.82%. This research is spurring the development of high-performance OSCs using solid additives that allow fine control during morphology development.