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Design strategy for ferroelectric-based polar metals with dimensionality-tunable electronic states
摘要： Since LiOsO3 was discovered, obtaining easy-accessible polar metals for research and applications has been challenging. In this paper, we present a multilayer design strategy, which is configured as ferroelectric layer/carrier reservoir layer/isolation layer/substrate, for obtaining polar metals by electrostatically doping a strained ferroelectric material in a more effective way. In the proposed configuration, both 1 unit-cell thick BaTiO3 and PbTiO3 exhibited considerable Ti off-centering with various strains, which should extend the applicability of ferroelectric-based polar metals in ultra-thin devices. Moreover, engineered by the compressive strain and the BaTiO3 thickness, the design strategy effectively achieved polar metallicity and dimensionality-tunable electronic states associated with the modulation of highly anisotropic properties such as electrical and electronic thermal conductivity, which may be helpful for designing ultra-thin, ultrafast, and low-power switch devices.
关键词： BaTiO3,design strategy,highly anisotropic conductivity,polar metal,electronic thermal conductivity,electrical conductivity
更新于2025-09-10 09:29:36
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Attaining reduced lattice thermal conductivity and enhanced electrical conductivity in as-sintered pure n-type Bi2Te3 alloy
摘要： Undoped n-type Bi2Te3 bulks were prepared via the liquid state manipulation (LSM) with subsequent ball milling and spark plasma sintering processes. The sample with LSM obtains higher carrier concentration and larger effective mass compared with that without LSM, exhibiting favourable electrical transport properties. More importantly, a much reduced lattice thermal conductivity * 0.47 W m-1 K-1 (decreased by 43%) is obtained, due to the enhanced multiscale phonon scattering from hierarchical microstructures, including boundaries, nanograins and lattice dislocations. Additionally, due to the increased carrier concentration and enlarged band gap, the bipolar effect is effectively suppressed in sample BT-LSM. Consequently, zTmax * 0.66 is achieved in the sample with LSM at higher temperature of 475 K, almost 22% improvement compared with that of the contrast.
关键词： spark plasma sintering,thermoelectric,electrical conductivity,thermal conductivity,liquid state manipulation,ball milling,Bi2Te3
更新于2025-09-09 09:28:46
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Decoupling the contributions to the enhancement of electrical conductivity in transparent silver nanowire/zinc oxide composite electrodes
摘要： Electrical properties of silver nanowire (AgNW)-based transparent electrodes have been improved without transmittance loss by forming a composite with zinc oxide (ZnO). Here, we identified the dominant effect responsible for the improvement of electrical conductivity of the transparent AgNW:ZnO composite electrodes by fabricating the AgNW:ZnO composite electrodes with different architectures and theoretically calculating the overall resistance of their equivalent circuits. Specifically, when we compared the overall resistances of the AgNW:ZnO electrodes with various architectures by experiment, the electrode with only the electrical bridge effect showed the lowest electrical resistance. In addition, while the theoretical overall resistances were comparable on changing the interconnect resistances between the silver nanowires in the equivalent circuits of all architectures, they decreased dramatically with the decreasing ZnO bridging resistance. Thus, it was concluded that the electrical bridge effect is more important than the capillary force effect which decreases the interconnect resistance between the silver nanowires for the enhancement of the electrical properties of AgNW:ZnO composite electrodes. It was also found that the AgNW:ZnO electrodes with only the electrical bridge effect showed better device performances when applied to optoelectronic devices such as organic photovoltaics.
关键词： electrical conductivity,silver nanowire,electrical bridge effect,zinc oxide,capillary force effect
更新于2025-09-09 09:28:46
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Room Temperature Bonding of Wafers Using Si and Ge Films with Extremely Low Electrical Conductivity
摘要： The technical potential of room temperature bonding of wafers in vacuum using amorphous Si (a-Si) and Ge (a-Ge) films was studied. Transmission electron microscopy images revealed no interface corresponding to the original films surfaces for bonded a–Ge–a–Ge films. Analyses of film structure and the surface free energy at the bonded interface revealed higher bonding potential at the connected a–Ge–a–Ge interface than that of a–Si films. The electrical resistivity of a-Ge films is 0.62 ?m, which is lower than that of a-Si film (4.7 ?m), but 7–8 order higher than that of representative material films used for bonding in vacuum. Our results indicate that room temperature bonding using a–Ge films is useful to bond wafers without any marked influence on the electrical properties of devices on wafer surfaces caused by the electrical conductivity of films used for bonding.
关键词： room temperature bonding,electrical conductivity,amorphous Ge,wafer bonding,amorphous Si
更新于2025-09-09 09:28:46
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A Review of Manufacturing Materials and Production Methods for Frequency-Selective Structures [Wireless Corner]
摘要： This article presents a review of frequency-selective structure (FSS) manufacturing materials and production methods ranging from the common printed circuit board (PCB)-based designs to textile, ink, metal, or fluid prototypes. Our work gathers some of the most relevant solutions published by the scientific community and considers several examples depicted for each case. Additionally, the main physical parameters that may have a significant impact on FSS performance have been identified, e.g., electrical conductivity of the FSS conductive element and the relative permittivity and thickness of the FSS dielectric material. Finally, a comparative analysis of the materials and techniques is presented, which highlights the benefits and limitations of each solution.
关键词： printed circuit board,relative permittivity,metal,Frequency-selective structures,fluid prototypes,textile,ink,electrical conductivity,production methods,manufacturing materials
更新于2025-09-09 09:28:46
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Influence of Al/Si atomic ratio on optical and electrical properties of magnetron sputtered Al1-xSixOy coatings
摘要： This work presents a study on the influence of the Al/Si atomic ratio in dc magnetron sputtered Al1-xSixOy amorphous and transparent films upon their chemical composition, films’ structure, optical and electrical properties. Increasing silicon in Al1-xSixOy films, from 0 at. % up to 31.1 at. %, caused an increment of deposition rate and an increment in Al-O-Si energy bonds as confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis. On other hand, the optical constants (refractive index (n) and extinction coefficient (k)), dielectric constant, loss tangent (tan δ) and ac conductivity (σac) decrease when the amount of silicon in films increased. The results show that the refractive index shows small variations from linearity with vol% of Al2O3 (or SiO2). Dielectric constant and dielectric loss evidenced two dipolar contributions, attributed to defects located one at or near the substrate/oxide interface, and the other in the bulk of the oxide.
关键词： Electrical conductivity,Sputtering,Dielectric properties,Aluminum silicon oxide,Optical properties
更新于2025-09-09 09:28:46
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Radiation Resistance of (HgSe)3(In2Se3)<Mn>
摘要： We present the results of studies of the effect of electron irradiation on the electrophysical parameters of (HgSe)3(In2Se3)<Mn> crystals, which are semimagnetic semiconductors with stoichiometric vacancies. It is shown that irradiation of (HgSe)3(In2Se3)<Mn> with high-energy electrons (Ee = 10 MeV, dose D = 1016 cm–2) has little effect on the electrophysical and magnetic properties, which indicates their high radiation resistance.
关键词： cluster,magnetic susceptibility,crystal,electrical conductivity
更新于2025-09-09 09:28:46
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Electrical Conductivity Modulation of Crosslinked Composite Nanofibers Based on PEO and PEDOT:PSS
摘要： The aim of this work is to investigate the development of nano?ber mats, based on intrinsically conductive polymers (ICPs), which show simultaneously a high electrical conductivity and mandatory insoluble water properties. In particular, the nano?bers, thanks to their properties such as high surface area, porosity, and their ability to o?er a preferential pathway for electron ?ow, play a crucial role to improve the essential characteristics ensured by ICPs. The nano?ber mats are obtained by electrospinning process, starting from a polymeric solution made of polyethylene oxide (PEO) and poly(styrene sulfonate) (PEDOT:PSS). PEO is selected not only as a dopant to increase the electrical/ionic conductivity, as deeply reported in the literature, but also to ensure the proper stability of the polymeric jet, to collect a dried nano?ber mat. Moreover, in the present work, two di?erent treatments are proposed in order to induce crosslinking between PEO chains and PEDOT:PSS, made insoluble into water which is the ?nal sample. The ?rst process is based on a heating treatment, conducted at 130°C under nitrogen atmosphere for 6 h, named the annealing treatment. The second treatment is provided by UV irradiation that is e?ective to induce a ?nal crosslinking, when a photoinitiator, such as benzophenone, is added. Furthermore, we demonstrate that both crosslinking treatments can be used to verify the preservation of nanostructures and their good electrical conductivity after water treatment (i.e., water resistance). In particular, we con?rm that the crosslinking method with UV irradiation results to being more e?ective than the standard annealing treatment. Indeed, we demonstrate that the processing time, required to obtain the ?nal crosslinked nano?ber mats with a high electrical conductance, results to being smaller than the one needed during the heating treatment.
关键词： PEO,PEDOT:PSS,intrinsically conductive polymers,electrical conductivity,nano?ber mats,water resistance,electrospinning,crosslinking
更新于2025-09-09 09:28:46
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Branched Side Chains Govern Counterion Position and Doping Mechanism in Conjugated Polythiophenes
摘要： Predicting the interactions between a semi-conducting polymer and dopant is not straightforward due to the intrinsic structural and energetic disorder in polymeric systems. Although the driving force for e?cient charge transfer depends on a favorable o?set between the electron donor and acceptor, we demonstrate that the e?cacy of doping also relies on structural constraints of incorporating a dopant molecule into the semiconducting polymer ?lm. Here, we report the evolution in spectroscopic and electrical properties of a model conjugated polymer upon exposure to two dopant types: one that directly oxidizes the polymeric backbone and one that protonates the polymer backbone. Through vapor phase in?ltration, the common charge transfer dopant, F4-TCNQ, forms a charge transfer complex (CTC) with the polymer poly(3-(2′-ethyl)hexylthiophene) (P3EHT), a conjugated polymer with the same backbone as the well-characterized polymer P3HT, resulting in a maximum electrical conductivity of 3 × 10?5 S cm?1. We postulate that the branched side chains of P3EHT force F4-TCNQ to reside between the π-faces of the crystallites, resulting in partial charge transfer between the donor and the acceptor. Conversely, protonation of the polymeric backbone using the strong acid, HTFSI, increases the electrical conductivity of P3EHT to a maximum of 4 × 10?3 S cm?1, 2 orders of magnitude higher than when a charge transfer dopant is used. The ability for the backbone of P3EHT to be protonated by an acid dopant, but not oxidized directly by F4-TCNQ, suggests that steric hindrance plays a signi?cant role in the degree of charge transfer between dopant and polymer, even when the driving force for charge transfer is su?cient.
关键词： semiconducting polymer,electrical conductivity,steric hindrance,dopant,charge transfer
更新于2025-09-09 09:28:46
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Surface plasmon induced atom localization in a tripod-type four level atomic system
摘要： We demonstrate the phenomenon of atom localization using surface plasmon polariton absorption/dispersion spectrums. A single and double localized peaks are measured on the absorption/dispersion spectrums of surface plasmon polariton at di?erent parameters and directions of propagation of the control ?elds. We show localized peaks with ～ 80% probability on dispersion spectrum and 50 % probability on the absorption spectrum. The localized peaks observed are shown to depend on strength of the control ?eld and the electrical conductivity.
关键词： surface plasmon polariton,atom localization,electrical conductivity,control ?elds,absorption/dispersion spectrums
更新于2025-09-09 09:28:46