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This study systematically investigated the electrorheological (ER) behavior of four aqueous smectite clay dispersions—fluorinated hectorite (Ht-F), stevensite (Stv), hectorite (Ht), and saponite (Sap)—with emphasis on transparency, rheological responses, and interparticle interactions. Optical observations revealed that the transparency of the aqueous dispersions followed the order Ht-F > Stv > Ht > Sap, which corresponded well to the finer network structures previously observed in Cryo-SEM images. Whereas micrometer-sized poly(methyl methacrylate) (PMMA) dispersions exhibited electrically induced rapid and reversible separation (ERS) due to sedimentation, the nanosized clays, which do not settle, developed ER effects through field-driven flocculation and subsequent network formation. Under low-frequency AC fields, Ht-F showed highly reversible responses similar to Stv, whereas Sap exhibited irreversible stress increases, accompanied by suspected ion release under the field. Dynamic rheological measurements showed that application of electric fields enhanced the loss modulus (G″) more prominently than the storage modulus (G′), clearly indicating a strengthening of viscous behavior. Derjaguin–Landau–Verwey–Overbeek theory (DLVO) potential analysis yielded a barrier-height sequence (Stv < Ht-F < Ht < Sap) that directly paralleled the order of ER responsiveness. These results demonstrate that the ER hierarchy of aqueous smectites can be rationalized by DLVO interactions and provide design guidelines for environmentally compatible ER fluids.

This paper presents a novel nanoscale tunnel FET consisting of an Esaki tunneling diode in the source region. A unique part of the source region is replaced by a heavily doped N-type silicon material establishing a tunneling diode inside the source region. Also, the gate metal is deliberately extended into the source region in order to more couple the created tunneling diode inside the source region. In the result of this new configuration, the band energy bending occurs inside the source region and also the potential barrier will be modified in the channel region thus increasing the ratio of I ON to I OFF (I ON /I OFF ) and reducing the leakage current and ambipolar current for the proposed structure. The proposed structure has been compared with the conventional TFET and PNPN-TFET structure in terms of the I ON /I OFF , Leakage current, ambipolar current, drain-source conductance, short channel effects, source-drain capacitance and minimum noise figure showing a performance superiority with respect to other structures under the study.

Quantum dot solar cells (QDSCs) were fabricated with a 2.8 nm Al 0.3 Ga 0.7 As potential barrier, and photoreflectance (PR) spectroscopy was performed to investigate the potential barrier effect in the localized electric field of QDSCs. PR spectroscopy was used to evaluate localized electric fields of QDSC with/without potential barrier through the FKO analysis. The PR spectra showed the optical transitions from QDs, wetting layer and Franz-Keldysh oscillation (FKO). When the QD embedded in Al 0.3 Ga 0.7 As potential barriers, spectral intensity of each transition was increased drastically due to the modulation efficiency increment caused by enhancement of carrier confinement between potential barrier. From the structural consideration, the electric field of 30.7 kV/cm originated from the p-i-n interface electric filed. On the other hand, the higher electric field of the 130 kV/cm originated from localized electric field from the QD region. The strength of localized electric fields of QDSC with potential barrier is smaller than those of QDSC without barrier because of the carrier confinement-induced field screening effect.

Perspective low-macroscopic field (LMF) emission prototype cathodes based on fullerene C60—doped porous silicon were realized via a two-stage technique comprising the electrochemical etching process of a monocrystalline silicon wafer and functionalization of the acquired porous silicon (PS) matrix with silver-doped fullerene-based carbon structures. The resulting LMF cathode prototypes were studied with SEM and EDS techniques. The formation of an amorphous silver-doped C60-based layer consisting of nanosized aggregates on the matrix surface was established. The emission characteristics of the prototypes were analyzed, crucial parameters including threshold field strength values, emission current density, and effective potential barrier height for electrons were considered. A novel LMF emission model is suggested. It was established that the emitter prototypes realized during this study are on par with or superior to modern and promising field cathodes.

The effective modeling methodology of 4H-SiC trench gate MOSFETs is presented. The potential barrier lowering at the MOS channel region suggested by I-V measurements is implemented to commercial TCAD tool as the net-doping reduction. The proposed model is validated by comparison of TCAD simulations with I-V measurements and SEM image observations.

The nucleophilic substitution reaction of activated aryl dihalide was used to synthesize heat-resistant thermoplastic polymers, that is, cardo co-poly(arylene ether ketone)s (co-PAEK) with different contents of fluorene fragments. Thermomechanical and electronic properties of thin films of the copolymers were studied, taking into account the prospects of their application for the formation of an electrical contact conducting oxide—polymer-metal. Influence of charge carrier concentration and effective mobility in the polymer were revealed depending on the composition of the cardo co-PAEK in the indium—tin oxide (ITO)—co-PAEK—copper structure. The potential barrier height at the co-PAEK—copper and co-PAEK—ITO interfaces was determined, the effect of changes of the electron work function of ITO on these values was studied. Changes in the parameters of charge carriers and changes in potential barriers over time were investigated.

The mechanism of charge carrier transport in the indium tin oxide (ITO)/polymer/Cu structure is studied, where thin films of copoly(arylene ether ketone) with cardo fluorene moieties are used. This copoly(arylene ether ketone) is non-conjugated polymer which has the properties of electronic switching from the insulating to the highly conductive state. The dependence on the polymer film thickness of such parameters as the potential barrier at the ITO/polymer interface, the concentration of charge carriers, and their mobility in the polymer is studied for the first time. The study of this system is of interest due to the proven potential of using the synthesized polymer in the contact system of a silicon solar cell with an ITO top layer. The parameters of charge carriers and ITO/polymer barrier are evaluated based on the analysis of current–voltage characteristics of ITO/polymer/Cu structure within the injection current models and the Schottky model. The thickness of the polymer layer varies from 50 nm to 2.1 µm. The concentration of intrinsic charge carriers increases when decreasing the polymer film thickness. The charge carrier mobility depends irregularly on the thickness, showing a maximum of 9.3 × 10−4 cm2/V s at 210 nm and a minimum of 4.7 × 10−11 cm2/V s at 50 nm. The conductivity of polymer films first increases with a decrease in thickness from 2.1 µm to 210 nm, but then begins to decrease upon transition to the globular structure of the films at smaller thicknesses. The dependence of the barrier height on polymer thickness has a minimum of 0.28 eV for films 100–210 nm thick. The influence of the supramolecular structure and surface charge field of thin polymer films on the transport of charge carriers is discussed.

This paper reports low temperature solution processed ZnO thin film transistors (TFTs), and the effects of interfacial passivation of a 4-chlorobenzoic acid (PCBA) layer on device performance. It was found that the ZnO TFTs with PCBA interfacial modification layers exhibited a higher electron mobility of 4.50 cm2 V−1 s−1 compared to the pristine ZnO TFTs with a charge carrier mobility of 2.70 cm2 V−1 s−1. Moreover, the ZnO TFTs with interfacial modification layers could significantly improve device shelf-life stability and bias stress stability compared to the pristine ZnO TFTs. Most importantly, interfacial modification layers could also decrease the contact potential barrier between the source/drain electrodes and the ZnO films when using high work-function metals such as Ag and Au. These results indicate that high performance TFTs can be obtained with a low temperature solution process with interfacial modification layers, which strongly implies further potential for their applications.

A mechanically induced artificial potential barrier (MIAPB) in piezoelectric semiconductor devices is set up under the action of a pair of tensile/compressive mechanical loadings. Three factors, namely, the barrier height, width and position, affect the nature and extent of interaction between the MIAPB and the contact barrier, and the tuning characteristics (generated under conditions of the artificial barrier) of the piezoelectric PN junctions were studied. The influence of these factors resulted in variations in the interaction intensities, superposition effects, carrier inversion degrees and carrier redistribution ranges. Subsequently, the limit tuning effects exerted by the tensile/compressive-mode MIAPB on the PN junctions were studied. The inconsistency between the left and right end of the tensile-mode MIAPB under conditions of the offset loading state proves that the maximum tuning effect is generated when both sides of the interface are symmetrically loaded. The range of carrier redistribution and the over-inversion of local carriers, affected by the width and height of MIAPB, result in a second competitive mechanism. The carrier redistribution range and the carrier inversion degree require that the compressive-mode MIAPB be sufficiently wide. The interaction intensities and the superposition effects, affected by the position and height of the MIAPB, contribute to the second competing mechanism. We logically clarify the relationship between multiple competition and find that the emergence of multiple competitive mechanisms proves the existence of the limit tuning effect of MIAPB on the I–V properties of PN junctions. The results reported herein provide a platform for understanding the mechanical tuning laws governing the functions of piezoelectric PN junctions and piezoelectric devices.

In this paper, an analytical expression of the electron spin-dependent tunneling current through a potential barrier by applying a bias voltage was investigated. An Airy wavefunction was applied to derive the transmittance through the barrier by considering a zinc-blende material, which depends on the spin states indicated as ‘up’ and ‘down’. The obtained transmittance was employed to compute the polarization and spin-dependent tunneling current. The spin-dependent tunneling current was then observed at various bias voltages and temperatures. It was shown that the spin-polarized current increases as the bias voltage increases. It was also shown that the increase of temperature enhances the spin-dependent tunneling current.