To understand the role of chlorine in the stability and the observed fragmentation of Ag dendritic nanostructures, we have studied computationally two model systems using density functional theory. The first one relates to diffusion of \documentclass[12pt]{minimal}\begin{document}$\textrm {Ag}_n$\end{document} Ag n and \documentclass[12pt]{minimal}\begin{document}$\textrm {Ag}_n\textrm {Cl}_m$\end{document} Ag n Cl m (n = 1–4) clusters on an \documentclass[12pt]{minimal}\begin{document}$\textrm {Ag}(111)$\end{document} Ag (111) surface, and the second demonstrates interaction strength of \documentclass[12pt]{minimal}\begin{document}$(\textrm {Ag}_{55})_2$\end{document}( Ag 55)2 dimers with and without chloridation. Based on our calculated energy barriers, \documentclass[12pt]{minimal}\begin{document}$\textrm {Ag}_n\textrm {Cl}_m$\end{document} Ag n Cl m clusters are more mobile than \documentclass[12pt]{minimal}\begin{document}$\textrm {Ag}_n$\end{document} Ag n clusters for n = 1–4. The binding energy between two \documentclass[12pt]{minimal}\begin{document}$\textrm {Ag}_{55}$\end{document} Ag 55 clusters is significantly reduced by surface chloridation. Bond weakening and enhanced mobility are two important mechanisms underlying corrosion and fragmentation processes.
The inherent advantages of 2D/2D S-scheme heterojunction contribute well to the photocatalysis due to efficient carriers’separation kinetics and maintained redox ability. However, single 2D/2D S-scheme heterostructure cannot produce a perfect energy band alignment effect since the material contact interface is not perfectly contacted in real circumstance because of surface roughness. Herein, the Schottky junction synergies with S-scheme (S-S strategy) is proposed to overcome the difficulty above. CNQDs are utilized to construct Schottky junction in S-scheme TCN/ZnIn 2S4 to optimize the carriers’ separation kinetics in some area without intimate contact of TCN/ZnIn2S4 . SI-XPS, UPS, and KPFM etc confirms such electron state in material. The CNQDs/TCN/ZnIn2S4 photocatalysts exhibits high degree of dissociation efficiency of photoinduced excitons due to S-S strategy. The results testify construction of S-S heterostructure would be an effective strategy for carriers’modulation, and it will be a promising candidate for “green” elimination of oil spill on water surface.
Different isotopes may exhibit different resistance against the displacement damage induced by neutron radiations. To examine the difference in silicon isotopes, we calculate the damage functions of 28Si, 29Si, 30Si and the natural silicon under intermediate neutron (10−6–0.1 MeV) and fast neutron (>0.1 MeV) radiations based on radiation damage theory and the Neutron Nuclear Reaction Evaluation Database (ENDF/B-VIII.0). Their accumulative displacement per atom (DPA) values under the neutron radiation of nuclear accident emergency response or cosmic space are also investigated. The calculated radiation damage functions and DPAs indicate that 30Si endures at least 10–15% less displacement damage compared with 28Si, 29Si and the natural silicon under intermediate and fast neutron radiations. Therefore, we propose to use 30Si-enriched silicon in semiconductor devices to enhance the neutron radiation resistance and extend the service life in radiative circumstances.
The gate-all-around (GAA) field-effect transistor (FET) holds great potential to support next-generation integrated circuits. Nanowires such as carbon nanotubes (CNTs) are one important category of channel materials in GAA FETs. Based on first-principles investigations, we propose that SiX2 (X = S, Se) nanowires are promising channel materials that can significantly elevate the performance of GAA FETs. The sub-5 nm SiX2 (X = S, Se) nanowire GAA FETs exhibit excellent ballistic transport properties that meet the requirements of the 2013 International Technology Roadmap for Semiconductors (ITRS). Compared to CNTs, they are also advantageous or at least comparable in terms of gate controllability, device dimensions, etc. Importantly, SiSe2 GAA FETs show superb gate controllability due to the ultralow minimum subthreshold swing (SSmin) that breaks "Boltzmann's tyranny". Moreover, the energy-delay product (EDP) of SiX2 GAA FETs is significantly lower than that of the CNT FETs. These features make SiX2 nanowires ideal channel material in the sub-5 nm GAA FET devices.
Abstract Intriguing “slidetronics” has been reported in van der Waals (vdW) layered non-centrosymmetric materials and newly-emerging artificially-tuned twisted moiré superlattices, but correlative experiments that spatially track the interlayer sliding dynamics at atomic-level remain elusive. Here, we address the decisive challenge to in-situ trace the atomic-level interlayer sliding and the induced polarization reversal in vdW-layered yttrium-doped γ-InSe, step by step and atom by atom. We directly observe the real-time interlayer sliding by a 1/3-unit cell along the armchair direction, corresponding to vertical polarization reversal. The sliding driven only by low energetic electron-beam illumination suggests rather low switching barriers. Additionally, we propose a new sliding mechanism that supports the observed reversal pathway, i.e., two bilayer units slide towards each other simultaneously. Our insights into the polarization reversal via the atomic-scale interlayer sliding provide a momentous initial progress for the ongoing and future research on sliding ferroelectrics towards non-volatile storages or ferroelectric field-effect transistors.
Abstract Two-dimensional (2D) van-der-Waals (vdW) layered ferroelectric semiconductors are highly desired for in-memory computing and ferroelectric photovoltaics or detectors. Beneficial from the weak interlayer vdW-force, controlling the structure by interlayer twist/translation or doping is an effective strategy to manipulate the fundamental properties of 2D-vdW semiconductors, which has contributed to the newly-emerging sliding ferroelectricity. Here, we report unconventional room-temperature ferroelectricity, both out-of-plane and in-plane, in vdW-layered γ-InSe semiconductor triggered by yttrium-doping (InSe:Y). We determine an effective piezoelectric constant of ∼7.5 pm/V for InSe:Y flakes with thickness of ∼50 nm, about one order of magnitude larger than earlier reports. We directly visualize the enhanced sliding switchable polarization originating from the fantastic microstructure modifications including the stacking-faults elimination and a subtle rhombohedral distortion due to the intralayer compression and continuous interlayer pre-sliding. Our investigations provide new freedom degrees of structure manipulation for intrinsic properties in 2D-vdW-layered semiconductors to expand ferroelectric candidates for next-generation nanoelectronics.
Elemental doping and surface modification are commonly used strategies for improving the electrochemical performance of LiMn2O4, such as the rated capacity and cycling stability. In this study, in situ formed core–shell LiZnxMn2–xO4@ZnMn2O4 cathodes are prepared by tuning the Zn-doping content. Through comprehensive microstructural analyses by the spherical aberration-corrected scanning transmission microscopy (Cs-STEM) technique, we shed light on the correlation between the microstructural configuration and the electrochemical performance of Zn-doped LiMn2O4. We demonstrate that part of Zn2+ ions dope into the spinel to form LiZnxMn2–xO4 in bulk and other Zn2+ ions occupy the 8a sites of the spinel to form the ZnMn2O4 shell on the outermost surface. This in situ formed core–shell LiZnxMn2–xO4@ZnMn2O4 contributes to better structural stabilization, presenting a superior capacity retention ratio of 95.8% after 700 cycles at 5 C at 25 °C for the optimized sample (LiZn0.02Mn1.98O4), with an initial value of 80 mAh g–1. Our investigations not only provide an effective way toward high-performance LIBs but also shed light on the fundamental interplay between the microstructural configuration and the electrochemical performance of Zn-doped spinel LiMn2O4.
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