The selective capture of trace Cs + from high‐salinity water remains challenging because of intense ionic competition and limited accessibility of internal ion‐exchange sites. Here, a mild ethanol–water hydrothermal treatment was employed to regulate the pore structure and defect environment of a Cu‐based Prussian blue analog (Cu‐PBA). The sample treated at 100 °C (CHF‐100) retained the original framework while exhibiting a more open porous structure and showing a possible increase in [Fe(CN) 6 ] vacancies, with its brunauer–emmett–teller (BET) specific surface area increasing from 92.1 to 137.3 m 2 g −1 . CHF‐100 reached near‐equilibrium within approximately 10 min, compared with approximately 30 min for pristine CHF, and its pseudo‐second‐order rate constant increased from 0.0534 to 0.1143 g mg −1 min −1 . In simulated seawater, the Cs + removal efficiency increased from 3.8% for pristine CHF to 73.7% for CHF‐100. In addition, CHF‐100 maintained a Cs + removal efficiency above 90% at Na + or Mg 2+ concentrations of up to 0.4 mol L −1 and at K + concentrations of up to 0.1 mol L −1 . The enhanced performance is associated with improved pore accessibility, defect‐related local structural changes, and facilitated Cs + mass transfer and K + /Cs + ion exchange.
Wide‐bandgap perovskites (WBGPVSK), as key top‐cell materials for tandem solar cells, are often limited by poor film crystallinity and interfacial defects. Herein, an ultrathin MACl interfacial layer is introduced between the hole transport layer and the perovskite in an inverted architecture to regulate the buried interface. The MACl interlayer effectively improves substrate wettability, facilitating uniform precursor spreading and enabling controlled nucleation, which promotes ordered crystal growth. As a result, the perovskite films exhibit enlarged grain size, reduced surface roughness, and suppressed void formation, along with enhanced optical absorption and improved crystallinity. Photoluminescence results reveal reduced carrier recombination and enhanced charge extraction. Consequently, the optimized device with 0.5 mg mL −1 MACl achieves a power conversion efficiency (PCE) of 22.79%, with the fill factor (FF) increased from 79.14% to 81.38%. This work demonstrates that buried interface engineering is an effective strategy to simultaneously regulate perovskite crystallization and interfacial charge transport for high‐performance WBGPVSK solar cells.
Exploring the spatial dependence of mediated exchange interactions is very useful to understand the mechanism of magnetic ordering and coupling of spin states. The confined structure and low spin‐decoherence channel of 7‐armchair graphene nanoribbon (7‐AGNR) offer a suitable platform to partially isolate the effect of substrate and visualize the competition between exchange interactions and Kondo screening. Herein, we use scanning tunneling methods to map the spatial dependence of local density of states between two unpassivated sites across the terminus of 7‐AGNR. A well‐pronounced pair of delocalized Kondo resonances was observed which gradually decay away from the scattering centers but still visible at any point along the line profile. This ubiquitous presence of the Kondo effect indicates mediated exchange interactions that may lead to magnetic ordering or exotic coupling between spin states. Although thermal decoherence weakens the signal intensity, temperature dependence shows that the interaction effects remain detectable at a relatively high temperature of 14 K. As the coupling strength of the two delocalized moments could be tuned by an electric field, this system offers great potential for applications in devices employing quantum information processing.
The global transition toward carbon‐neutral energy systems has intensified research on safe, efficient, and high‐density hydrogen storage materials. Among solid‐state systems, hydride perovskites have recently emerged as promising candidates due to their tunable crystal chemistry, structural versatility, and potential for reversible hydrogen absorption. However, experimental progress on hydride perovskites remains limited, and much of the current understanding is driven by first‐principles density functional theory (DFT) investigations. This review provides a comprehensive assessment of DFT studies on hydride perovskites, highlighting their structural stability, electronic behavior, mechanical properties, thermodynamic properties, and hydrogen storage performance. Moreover, practical applicability and synthesizability of DFT‐predicted hydride perovskites can be evaluated through several key computational indicators, which are discussed in detail. We critically examine the predictive capabilities of DFT in modeling these materials, discuss trends across different compositional families, and identify key descriptors that influence hydrogen uptake and release. Furthermore, we outline experimentally relevant insights derived from first‐principles calculations and propose directions for future synthesis and characterization. By consolidating theoretical advances and mapping existing knowledge gaps, this review aims to guide both computational and experimental efforts toward the practical development of perovskite‐based hydrogen storage materials.
In this paper, a method to optimize the gate‐induced drain leakage (GIDL) and negative differential resistance (NDR) in a negative capacitance (NC) silicon on insulator (SOI) FinFET is proposed. Optimization is achieved by tuning the energy band to reduce the Miller capacitance. A four‐order improvement in GIDL is observed with the proposed method. The NDR of the device is optimized for the considered channel length of 20 nm, which is reflected as a 4% improvement in the voltage gain of the common‐source (CS) amplifier. The ferroelectric polarization is improved at the drain end of the channel. The improvements in GIDL and NDR are achieved with subthreshold swing (SS) intact around 57 mV/decade and a change in negative DIBL (N‐DIBL) of 3 mV/V. The switching performance comparison of the device is estimated with a CMOS Inverter for the considered drain‐doping profiles. It shows improvements in the rise and fall times and a two‐order‐of‐magnitude reduction in off‐state leakage. Analog/RF efficiency metrics, transconductance efficiency, and energy‐speed product are retained and improved, respectively.
Ga‐doped continuously Czochralski silicon (CCz‐Si) is promising for p‐type silicon solar cells due to its superior axial resistivity uniformity, high productivity, and immunity to light‐induced degradation (LID). However, multiple crucibles designing and prolonged operation duration lead to more severe erosion of crucibles, resulting in higher concentration of oxygen and metal impurities (particularly iron). This study elucidates the role of iron contamination in promoting oxygen precipitation and modifying the electrical activity of oxygen precipitates (OPs). By combining electron beam‐induced current (EBIC), deep‐level transient spectroscopy (DLTS), and Fourier‐transform infrared spectroscopy (FTIR), it is demonstrated that iron significantly enhances the nucleation of oxygen precipitates. Critically, we identify an evolutionary pathway where FeGa pairs dissociate upon annealing to form intermediate FeO complexes ( E v + 0.33 eV, σ p = 3.2 × 10 −16 cm −2 ). These FeO complexes are likely to serve as highly effective heterogeneous nucleation centers, accelerating oxygen precipitation and leading to a higher density of OPs with deeper energy level and increased carrier capture cross section. These findings provide a mechanistic understanding of iron–oxygen‐dopant interactions in Ga‐doped CCz‐Si, offering crucial insights for defect engineering to mitigate the detrimental effects of metal impurities in cost‐effective photovoltaic silicon.
The structural, electronic, magnetic, elastic, thermodynamic, optical, and thermoelectric properties of Heusler alloy were studied in the XA and ordered phases within the framework of density functional theory. The calculated total energies reveal that the ordered phase is the most stable configuration in the ferromagnetic state under the GGA + U approximation. The total magnetic moments of in both the XA and structures are consistent with the Slater–Pauling relation . Analysis of the density of states and band structure reveals that the phase of the compound exhibits metallic nature in spin‐up and spin‐down orientations, whereas the XA phase is half‐metallic. The results of the elastic‐property analysis indicate that both studied phases exhibit elastic anisotropy and satisfy Born's mechanical stability criteria. Furthermore, the thermodynamic properties were evaluated using the quasi‐harmonic Debye model implemented in the Gibbs code. The optical properties were investigated in detail through a systematic calculation of the relevant optical parameters. Regarding the thermoelectric behavior of the two phases, the transport coefficients were analyzed over the temperature range of 50–800 K.
Half-metals are promising candidates for spintronic applications due to the complete spin polarization at the Fermi level. Recently, ferromagnetic half-metallic NiMnSb has regained considerable research attention owing to its nontrivial topological properties. For example, Singh et al. found that the Weyl node in NiMnSb produces anomalous Hall conductivity [Adv. Sci. 11, no.31 (2024): 2 404 495]. In this work, we design an AlAs/NiMnSb heterostructure and a magnetic tunnel junction (MTJ) NiMnSb/AlAs/NiMnSb to explore the potential spintronic applications of half-metallic NiMnSb. Density functional theory combined with non-equilibrium Green's function method reveals that the heterostructure exhibits an ideal thermal spin filtering effect and a spin diode effect. In addition, the MTJ has a large tunnel magnetoresistance ratio up to 3.7 & times; 105% at room temperature. These phenomena can be understood from the spin-dependent band structure and transmission spectrum. These results highlight the promising potential of NiMnSb for spintronic devices.
In this study, molybdenum disulfide (MoS 2 ) was doped into a solution of indium oxide (In 2 O 3 ) precursor to fabricate thin‐film transistors (TFTs) by a solution‐based process. Although solution‐based metal oxide TFTs have the advantages of low‐cost fabrication, large‐area preparation, and easy processing, they still suffer from relatively poor film quality and poor electrical properties compared with vacuum deposition TFTs. To address these issues, we have introduced a ultraviolet (UV)/ozone annealing post‐treatment process to improve film quality and device performance. The In 2 O 3 /MoS 2 TFTs treated under 1 min UV/ozone showed the best performance with I on / I off reaching 1.0 × 10 7 from 1.4 × 10 5 . This study highlights the synergistic effect of MoS 2 doping and UV/ozone treatment process in optimizing the low‐temperature solution‐prepared In 2 O 3 /MoS 2 TFTs.
This study investigates the behavior of a Threshold-Changeable Memory (TCM) device based on an amorphous GeSbSeN (GSSN) alloy. A dedicated programming protocol is optimized to induce polarity-dependent threshold voltage modulation. Building on this programming protocol, the influence of elemental composition, particularly variations in Sb and N content, is examined to determine its effect on the achievable MW and the efficiency of the programming process. In addition, a systematic time-dependent drift analysis is performed as a function of Sb content to investigate the impact of Sb incorporation on threshold voltage stability. Activation energy extraction and temperature-dependent measurements are performed to provide further insight into the mechanisms responsible for polarity-induced threshold voltage modulation. These results offer key insights about the origin of the TCM mechanism in GSSN alloys and establish a solid foundation for the future development of this emerging memory technology.
The fabrication of group-IV superconducting semiconductors has received considerable attention owing to their potential for integration with hybrid semiconductor-superconductor circuits. In this context, superconducting germanium-on-insulator (GeOI) is particularly promising, as it can fully exploit the advantages of the GeOI technologies for advanced electronic devices. In this study, we demonstrate superconductivity in GeOI via Ga ion implantation and millisecond-range flash-lamp annealing (FLA). Electrical measurements showed an activated hole concentration of approximately 8 & times; 1020 cm-3, with a superconducting transition temperature of around 150 mK. Additionally, the critical magnetic field aligns well with the behavior expected for diluted superconducting semiconductors. The superconducting GeOI provides a foundational platform for potential applications in future quantum devices.
Amorphous germanium sulfide(a-GeS) holds significant promise as a threshold-switching selector material for three-dimensional crossbar memory applications. In this study, we employ ab initio molecular dynamics simulations to investigate the effects of silicon (Si) doping on the structural and electronic properties of a-GeS, aiming to enhance its ovonic threshold switching (OTS) performance. Our results reveal that Si doping leads to the formation of strong Si-Si and Si-S bonds within the amorphous network. Si-centered clusters predominantly adopt tetrahedral configurations, and the fraction of Ge-centered tetrahedra also increases, contributing to enhanced structural stability. Furthermore, the mobility gap narrows in Si-doped a-GeS (a-SiGeS), while the mid-gap states increase, enabling it to still maintain a relatively high threshold voltage. Importantly, atomic mobility is significantly suppressed in a-SiGeS, which is expected to improve cycling endurance. These findings highlight Si doping as an effective strategy for tailoring the performance of amorphous chalcogenide selectors, positioning a-SiGeS as a promising material candidate for high-density nonvolatile memory.
Electrostatic capacitors based on hafnium–zirconium oxide (HZO) have attracted considerable attention as scalable, CMOS‐compatible candidates for next‐generation energy storage. Despite their fast charge–discharge capability and high power density, their application remains limited by low energy storage density (ESD) and efficiency, mainly constrained by polarization saturation and hysteresis losses. Although compositional engineering has been explored to enhance the antiferroelectric (AFE) or negative capacitance (NC) behavior of HZO, understanding how the Hf:Zr ratio governs NC onset voltage and its correlation with energy storage remains incomplete. Here, we systematically investigate the role of Hf:Zr composition in bilayer HZO capacitors to identify the optimal ratio balancing performance and reliability. Increasing the Zr fraction from 1:1 to 1:3 in both layers improves recoverable ESD from 62.7 to 82.1 J cm −3 and efficiency from 88% to 91%, enabled by delayed NC onset and enhanced charge amplification. This enhancement originates from a higher tetragonal‐phase fraction, elevating the NC onset voltage and widening the stable NC window while suppressing charge injection and hysteresis losses. These findings establish a compositional design rule for HZO‐based NC supercapacitors, providing a pathway toward high‐efficiency, fatigue‐resistant, and energy‐autonomous electronic systems.
In this study, we investigate the electronic and optical properties of silicon‐doped β‐Ga 2 O 3 using first‐principles calculations. Four key defect configurations were analyzed: substitutional Si on a tetrahedral Ga site (Si GaI ), interstitial Si (Si i9 ), and the interstitial Si–Ga vacancy complexes Si i9 –1V GaI and Si i9 –2V GaI . We confirm that the substitutional Si GaI acts as a shallow donor, raising the Fermi level into the conduction band, which is consistent with experimental data. In contrast, the interstitial Si i9 introduces a midgap level and exhibits a smaller Bader charge compared to the substitutional case, deviating from the +4‐oxidation state typically observed experimentally. Crucially, complex formation with Ga vacancies stabilizes the interstitial species. The Si i9 –1V GaI complex retains n‐type behavior with a redshifted absorption edge. The Si i9 –2V GaI complex, however, introduces deeper states and a further reduced optical absorption edge below 4 eV. The comparable Bader charge and negative formation energy of these two complexes indicate that they can coexist with substitutional donors under implantation conditions. Our results provide novel insight into the mechanism behind the experimentally observed dual nature of Si in β‐Ga 2 O 3 .
Phase Change Memory is a leading emerging nonvolatile memory technology based on the reversible switching between amorphous and crystalline states in Ge‐Sb‐Te alloys. Repeated phase transitions induce elemental redistribution, generating local stoichiometry variations that critically influence device performance. Accessing different compositions within a single specimen is therefore essential for understanding phase change memory (PCM) behavior. We present a deposition methodology enabling the simultaneous formation of phase‐change alloys with nanoscale compositional gradients. The approach uses three Knudsen cells supplying Ge, Sb, and Te, each oriented at 45° relative to the substrate normal. The substrate includes cylindrical nanopillar arrays produced by electron beam lithography, which generate controlled shadowing effects and spatial modulation of the elemental flux. Local composition was characterized using scanning transmission electron microscopy and electron energy loss spectroscopy. The elemental profiles were compared with a ballistic transport model describing trajectories around nanopillars. The experimental and simulated data show agreement. Simulations performed with an alternative configuration, where the three cells are spaced 120°, predict predefined Ge, Sb, and Te‐deficient regions around the pillars. This methodology enables controlled nanoscale stoichiometry engineering and provides a powerful platform for studying composition‐dependent phase‐change mechanisms, supporting the optimization of PCM device performance.
The tribological performance of additively manufactured Ti6Al4V alloy is strongly influenced by its metastable microstructure and surface condition. This work investigates the effect of shot peening with ceramic beads and CrNi steel shots on the friction and wear behavior of DMLS‐fabricated Ti6Al4V under technically dry sliding conditions using a ball‐on‐disc configuration with an Al 2 O 3 counterbody. Shot peening led to a significant increase in surface hardness (up to ∼42%) and a reduction in surface roughness, resulting in lower friction coefficient and wear rate compared to the as‐built condition. Despite similar hardness and roughness levels, distinct tribological responses were observed depending on the peening media. SEM and EDS analyses revealed phase‐dependent wear mechanisms, indicating that shot‐induced redistribution of the metastable α′ and β phases plays a key role in governing wear behavior.
Recently, SnO 2 has emerged as a promising core material for low‐cost, high‐performance photodetectors due to its excellent comprehensive properties. However, its narrow spectral response range limits its application in broadband detection. In this study, Bi 2 S 3 nanorods were fabricated for the first time via a sol‐gel method on a SnO 2 thin film, constructing a Bi 2 S 3 /SnO 2 /p‐Si (BSS) heterojunction photodetector. The structural and morphological characteristics of the BSS heterojunction were examined using X‐ray diffraction and scanning electron microscopy. Optical and electronic spectral analyses (absorption spectroscopy and ultraviolet photoelectron spectroscopy) confirmed that the BSS formed a well‐defined vertical heterostructure, enabling the device to detect UV‐Vis‐NIR light spanning 365‐1305 nm. At a 5 V bias under 780 nm light, the BSS heterojunction photodetector exhibited a high switching ratio of 2.19 × 10 4 , a rapid decay time of 28.86 ms, a responsivity of 2.21 A/W, and a specific detectivity of 3.92 × 10 12 Jones. Band alignment analysis shows a type‐II (Bi 2 S 3 /SnO 2 ) and a type‐I (SnO 2 /p‐Si) alignment, respectively, thus providing an effective band structure for efficient carrier separation and recombination suppression. This work demonstrates the significant potential of the high‐performance SnO 2 ‐based heterojunction photodetector for broadband detection applications.
The application of 3D crosspoint memory for low‐power and high‐density data storage relies critically on ovonic threshold switching (OTS) selector devices. To address the requirements of low leakage current and high thermal stability, Ge 20 As 28 Se 48 Te 4 (GAST) chalcogenide alloys are investigated as OTS selector materials by synergistically integrating the excellent switching characteristics of GeTe, the enhanced thermal stability of GeSe–GeTe systems and As incorporation. The GAST‐based OTS devices exhibit outstanding thermal stability (retaining functionality after annealing at 400°C for 30 min), ultralow off‐state current, fast switching speeds, and robust endurance exceeding 10 8 switching cycles. Raman spectroscopy and X‐ray photoelectron spectroscopy reveal annealing‐induced local structural rearrangements and bonding evolution without macroscopic crystallization. First‐principles calculations further corroborate these observations, showing enhanced short‐range order in the radial distribution functions and a stable electronic density of states upon annealing. These experimental and theoretical results elucidate the excellent thermal stability and reliable switching behavior, providing valuable insights for the design of highly reliable OTS selectors for advanced 3D crosspoint memory applications.
CsPbBr 3 nanocrystals (CPB NCs), an all‐inorganic halide perovskite, have demonstrated high efficiency and significant commercialization potential in fields such as light‐emitting diodes, solar cells, photodetectors, lasers, and bioimaging. However, the instability of CPB NCs in ambient environments remains a major challenge that must be addressed before their widespread commercial applications. Core–shell structural engineering of CPB NCs has been widely employed to mitigate the impacts of external environmental factors, significantly enhancing long‐term stability against moisture, thermal, and oxygen. A protective shell layer covering CPB NCs prevents direct exposure to these environmental factors, providing excellent stability. This review summarizes recent advancements and challenges in CPB NCs‐based core–shell materials, systematically analyzing how shell material types and bandgap structures influence luminescence stability. The energy band structure and configuration of CPB NCs‐shell are discussed in detail, and the classification of shell types, such as perovskite and its derivatives, oxide shells, and polymer shells in single‐layer configurations, is reviewed. Special attention is given to the applications of the CPB NCs‐based core–shell materials with enhanced stability. Finally, the main challenges and further research directions for the core–shell structure of CPB NCs are discussed, with the aim of promoting the development of stable metal halide perovskite materials in the future.
