Journal of Electronic Materials最新文献

The structural, elastic, electronic, and thermodynamic properties of a LiScSi_1−xC_x alloy in the α-phase were investigated using density functional theory with the plane-wave pseudopotential method and the alchemical mixing approximation in ABINIT code. We computed ground-state properties including lattice constants, bulk modulus, energy gap, refractive index, and optical dielectric constant for the LiScSi_1−xC_x compounds. Our results align well with existing theoretical data for the parent compounds LiScSi and LiScC. We found that the fundamental bandgap for the α-LiScSi_1−xC_x alloy varied from 0.865 eV to 1.143 eV using the B3LYP approach, indicating potential applications in optoelectronic devices such as photodetectors and light-emitting diodes (LEDs), where precise control over electronic and optical properties is crucial. Additionally, we calculated the electron and hole effective masses, which showed a decrease with increasing carbon concentration; the electron effective mass ranged from 0.042m* for LiScSi to 0.035m* for LiSiC. The LiScSi_1−xC_x alloy in the α-phase consistently exhibited direct semiconductor behavior (X → X) across all concentrations. We also predicted the variation in thermodynamic properties, including unit cell volume, bulk modulus, heat capacity, and thermal expansion coefficient, with temperature for various carbon concentrations. These findings contribute to a deeper understanding of the material’s potential applications in electronic and thermoelectric devices.

Thermoelectric materials possess the capability to convert electricity into heat and vice versa. The utilization of chlorofluorocarbons and hydrochlorofluorocarbons as thermal carrier agents in traditional cooling and air conditioning systems has sparked a surge in exploration toward pioneering refrigeration and spatial conditioning technologies. Chalcogenides, known for their capacity to amplify the thermoelectric efficiency of materials and their adaptability across a broad spectrum of temperatures, stand out as pivotal components in thermoelectric materials. Despite their existing suboptimal performance, these materials hold substantial promise as power generators and as solid-state Peltier coolers, attracting significant attention and positioning them as subjects ripe for further investigation. Categorized into alkali or alkaline earth, transition metal, and main-group chalcogenides, these materials and their respective subclasses are meticulously scrutinized to pinpoint the most suitable thermoelectric materials for specific applications with an optimal operational temperature span. In the quest for energy-efficient technologies characterized by simple designs, absence of moving components, and superior stability, thermoelectric materials play a crucial role. This review highlights the advancements in theoretical parameters as well as the figure of merit (ZT) of chalcogenide materials, emphasizing their device applications. These insights are intended to provide viable future approaches to mainstream thermoelectric materials. This review reveals that Cu₂Se achieves a maximum ZT value of 2.66 at 1039 K, marking it as the top performer among transition metal chalcogenides. Conversely, SnSe, a main-group metal monochalcogenide, exhibits a ZT value of 2.8 at 773 K, whereas nanowires of the main group of bismuth chalcogenides exhibit a ZT value of 2.5 at 350 K.

As the global lithium-ion batteries (LIBs) market continues to expand, the necessity for dependable and secure LIBs has reached an all-time high. However, the use of batteries is associated with a number of significant risks, including the potential for thermal runaway and explosions. The meticulous inspection of LIBs is not only essential for guaranteeing their quality and functionality, but also for ensuring their safety. This underscores the criticality of advanced inspection technologies. In contrast to traditional inspection technologies, industrial x-ray computed tomography (CT) scanning technology affords a non-destructive comprehensive, three-dimensional insight into the interior structure of a battery without the need for disassembly. It can make the inner LIBs structures visible through the housing and even batteries already installed in devices can be examined safely and accurately without being removed or opened. This capability is of critical importance for the identification of defects that could lead to battery failure or safety issues, and guide the optimization of LIBs with better safety and performance. This perspective review briefly summarize the comprehensive application of industrial CT in LIBs including battery materials, cells and modules. Finally, we further discuss the challenges and prospects of industrial CT for energy storage.

Sn-Ag-Cu (SAC) has emerged as one of the most widely accepted lead-free solders used as interconnecting material in electronic packaging. However, these systems still have major reliability problems. During manufacturing, the interfacial reaction of Cu with molten Sn-based solder results in the formation of brittle intermetallic compounds (IMC) that accelerate the degradation of these systems. The evolution of IMC follows during operation due to electromigration (EM), which in addition is responsible for Cu depletion. Both mechanisms are strongly affected by the anisotropic diffusion of Sn resulting in large variability of solders life time prediction. We developed a model to study the formation and evolution of IMC and the diffusion of copper due to EM that includes the impact of Sn crystal orientation on solder failure during fabrication and operation. Our findings show that IMC growth is polarized during electromigration, accelerating at the anode and slowing at the cathode. Similarly, copper depletion is more pronounced at the cathode. The anisotropy of Sn strongly affects the rates of IMC growth and copper depletion during electromigration, shaping solder failure during operation.

The well-known Rule07 is a simple thus efficient way to compare available technologies for IR imaging detectors in terms of dark current. The noise is then often estimated using a shot noise approximation on the dark current. Both II–VI and III–V communities use this rule of thumb as a reference for well-performing IR photodiodes. For HOT applications, a dark current close to this rule07 is considered a necessary condition but not a sufficient one to obtain a high-performance IR imager. Indeed, when limited by shot noise, rule07 describes well the noise behavior of the considered device. However, when considering low-frequency noise, it fails to describe the expected performances. In this paper, we focus on another figure-of-merit, dedicated to detector low-frequency noise rather than dark current. Systemic 1/f noise investigation in an IR detector was first reported by Tobin et al. in 1980. There is today a relative consensus on the fact that measured 1/f noise is proportional to the dark current. The ratio between the amplitude of the 1/f noise and the dark current of the same devices may therefore be used as a figure-of-merit for a given technology. This ratio (called the Tobin factor ({alpha }_{text{T}})) therefore appears adequate to compare different technologies as a figure-of-merit qualifying 1/f noise properties. This dimensionless ratio can also be very useful for optimizing a particular technology or process. However, in order to be relevant, this figure-of-merit must be estimated carefully as it appears, for instance, pixel pitch-dependent. Different examples of Tobin coefficient extraction are presented in this paper. We show that, depending on the technologies, the values of the Tobin coefficient can spread over several orders of magnitude. However, only low values result in high-quality IR imagers. Today, the best results we obtained show that ({alpha }_{text{T}}={10}^{-5}) is a state-of-art value to be compared with.

A popular class of efficient energy harvesting technologies is the triboelectric nanogenerator (TENG). There has been considerable research demonstrating the feasibility of converting mechanical motions into electrical energy by using these devices. In the design of TENGs, the power generated and its optimization are the most important aspects. However, not all factors affecting TENG performance are well understood. The main criteria for choosing materials is surface charge density, flexibility, and mechanical resistance. In some types of TENGs that are time-varying capacitors, the dielectric constant of the material can be a significant factor affecting the performance of these nanogenerators. In this research, using simulation, we investigate the effect of increasing the dielectric constant on the performance of the TENG in the contact-separation model (CSTENG). We find that increasing the dielectric constant is very effective in thick structures; it boosts the charge transferred under short-circuit conditions (Q_SC), current, maximum power, and figure of merit. However, there is little effect of the dielectric constant on thin CSTENG performance. Hence, the high-K material utilization effect is relaxed by thin dielectric layers. We then analyze the conditions of frequency matching and we obtain the optimal condition to achieve maximum power. To achieve optimal power output, thin CSTENGs require materials with a low dielectric constant. In contrast, thick structures can be optimized by utilizing high-K materials. Based on these findings, design rules for TENGs can be derived.

Graphical Abstract

In this study, La_0.63Sr_0.2Nd_0.17MnO₃ was synthesized by the sol-gel method, and its structural, morphological, magnetic, and magnetocaloric effects were investigated. The structural properties were analyzed by x-ray diffraction (XRD), and scanning electron microscopy (SEM) was used to characterize the morphology. An integrated magnetic measurement system was used to determine the magnetic properties. La_0.63Sr_0.2Nd_0.17MnO₃ crystallized in a hexagonal crystal system with space group R-3c. This was also confirmed by Rietveld refinement of the x-ray data from La_0.63Sr_0.2Nd_0.17MnO₃. With the doping of Nd³⁺, the cell volume decreases, which can be explained by the angles and bond lengths of the bonds between the Mn and O ions and the distortion of the lattice. Near the Curie temperature, La_0.63Sr_0.2Nd_0.17MnO₃ exhibits significant magnetocaloric effects. The magnetic study of La_0.63Sr_0.2Nd_0.17MnO₃ suggests that the transition from the paramagnetic to ferromagnetic phase can occur near the Curie temperature. The maximum magnetic entropy change and relative cooling power (RCP) of La_0.63Sr_0.2Nd_0.17MnO₃ (298 K, 3 T) are 2.70 J/(kg K) and 135 (J/kg), respectively. The effect of f-orbitals on the magnetic properties of La_0.8Sr_0.2MnO₃ was investigated by first-principles calculations in density functional theory. Thus, it can be concluded that the magnetocaloric effects of the material after doping with f-orbital ions (Nd³⁺) is enhanced compared to La_0.8Sr_0.2MnO₃.

This study is the first to explore the effect of selenium doping on the electronic properties of β-Ga₂O₃ through first-principles calculations. Selenium doping in β-Ga₂O₃ is a significant choice, as it has the potential to improve the material’s electronic properties. Previous work on β-Ga₂O₃ has focused primarily on other dopants, and the effect of selenium doping is not well understood. Therefore, this study fills an important gap in the current understanding of β-Ga₂O₃ doping. Selenium doping in β-Ga₂O₃ was studied by first-principles calculations with a hybrid functional, as this functional can offer a more accurate description of electronic properties, resulting in accurate electronic bandgap and defect level calculations. Our first-principles calculations reveal that selenium can be incorporated on both Ga and O sites under specific conditions. Specifically, under O-rich conditions, selenium atoms are more likely to substitute the Ga sites, whereas under Ga-rich conditions, they are more likely to substitute the O sites. With the formation energy analysis, our findings indicate that selenium doping on Ga sites can lead to n-type conductivity, with it acting as shallow donor. On the other hand, Se dopants at the O sites exhibit deep donor characteristics, rendering it ineffective in regulating the conductivity of β-Ga₂O₃ materials. Our findings suggest that Se can be used as a dopant to tune the β-Ga₂O₃ conductivity for electronic and photonic applications, provided that the atomic substitution on Ga sites can be effectively controlled. Our results will provide valuable theoretical insights for the refined use of selenium dopants in β-Ga₂O₃, as well as guidance and theoretical support for subsequent researchers in the selection of Ga₂O₃ dopants.

Composites of polyvinyl alcohol and polyvinyl pyrrolidone (PVA/PVP) reinforced with different silicon dioxide (SiO₂) loadings (0, 2, 4, and 6) wt.% were obtained via the solution casting method. The electrical and optical properties have been investigated. Fourier-transform infrared ray (FTIR) analysis revealed that the incorporation of SiO₂ NPs resulted in an interaction with the polymer matrix. Physical interactions between the (PVA/PVP) polymer matrix and SiO₂ NPs have been shown by FTIR analysis. The increase in SiO₂ nanoparticle ratio in the PVA/PVP/SiO₂ nanocomposite results in a corresponding increase in absorbance and decrease in transmittance. The PVA/PVP/SiO₂ nanocomposite exhibited a reduction in energy gap, decreasing from 4.2 eV observed in pure PVA/PVP to 2.6 eV for allowed indirect transition and 4 eV to 2.6 eV for forbidden indirect transition, upon the incorporation of SiO₂ nanoparticles at a concentration of 6 wt.%. This result is deemed a key for various optical fields and optoelectronics nanodevices. The weight percentages of SiO₂ nanoparticles exhibit a positive correlation with their absorbing coefficient, extinction coefficient, index of refractive, real and imaginary components of dielectric constants, and optical conductivity. The investigation of the nanocomposites has revealed that an increase in the concentration of SiO₂ nanoparticles leads to an elevation in both the dielectric constant and dielectric loss, while an increase in the frequency of the applied electric field results in a decrease in these properties. The increase in frequency and weight content of SiO₂ NPs results in a corresponding increase in AC electrical conductivity. The results confirm that PVA/PVP/SiO₂ films nanocomposites have excellent optical and electrical properties, which could encourage the nanocomposites' application in different electric and optoelectric uses.