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This study investigates the quantum size effect on the energy spectrum of the exciton as a charge carriers confined in a core–shell of spherical and cubic GaAs/Al x Ga 1-x As quantum dots with finite potential barrier specified as a function of the doping material. The calculations indicated the inverse relationship between the confinement energy values of the first three energy levels and the dot volumes. In comparing the energy levels of the two shapes, results indicated that the energy values for the first two levels of the spherical dot are lower than those for the cubic one, however for the third level the energy of the spherical dot is larger than that for the cubic dot. Tunneling effects are studied by calculating the transmission coefficient related to each energy level. The results exhibited that larger values correspond to the excitons in the second excited state and small dot volumes. Additionally, increasing the doping values enhanced decreases in the transmission coefficient values. Finally, calculation to the wavelength of the emitted light from the ground state energy level illustrated that the emitted wavelengths more precisely affected by the dot compositions. The emitted light wavelength from the ground state energy level is also examined. For x = 0.2, the emitted wavelengths range from 658.7 to 721.8 nm for spherical Quantum dots and 649.5 to 720.3 nm for cubic Quantum dots across all volumes. For x = 0.4, the emitted wavelengths fall within the yellow light range (571–586.6 nm) for small Quantum dots (125–216 nm 3 ), the orange light range (597.9–624.8 nm) for medium-sized Quantum dots (343–1728 nm 3 ), and the red-light range (627.4–631.2 nm) for larger Quantum dots (2197–3375 nm 3 ). These findings contribute to the development of more efficient optoelectronic devices and quantum computing components by providing insight into quantum confinement and light emission properties in nanostructured materials.

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.

Using a one-dimensional minisuperspace model with a dimensionless ratio EEPl , we study the initial singularity problem at the quantum level for the closed rainbow cosmology with a homogeneous, isotropic classical space-time background. We derive the classical Hamiltonian within the framework of Schutz’s formalism for an ideal fluid with a cosmological constant. We characterize the behavior of the system at the early stages of the universe evolution through analyzing the relevant shapes for the potential sector of the classical Hamiltonian for various matter sources, each separately modified by two rainbow functions. We show that for both rainbow universe models presented here, there is the possibility of eliminating the initial singularity by forming a potential barrier and static universe for a non-zero value of the scale factor. We investigate their quantum stability and show that for an energy-dependent space-time geometry with energies comparable with the Planck energy, the non-zero value of the scale factor may be stable. It is shown that under certain constraints the rainbow universe model filled with an exotic matter as a domain wall fluid plus a cosmological constant can result in a non-singular harmonic universe. In addition, we demonstrate that the harmonically oscillating universe with respect to the scale factor is sensitive to EEPl and that at high energies it may become stable quantum mechanically. Through a Schrödinger–Wheeler–De Witt equation obtained from the quantization of the classical Hamiltonian, we also extract the wave packet of the universe with a focus on the early stages of the evolution. The resulting wave packet supports the existence of a bouncing non-singular universe within the context of gravity’s rainbow proposal.

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.

We report on the results of investigations of the millimeter-wave field-effect transistors with a 0.14‑μm T -shaped gate with pseudomorphic Al 0.3 Ga 0.7 As–In 0.22 Ga 0.78 As–Al 0.3 Ga 0.7 As heterostructures with additional potential barriers based on a two-sided donor–acceptor channel doping. At a frequency of 40 GHz in a wide gate voltage range, the maximum stable gain of more than 15 dB has been obtained. The maximum oscillation frequency of the device is about 250 GHz, the open-channel specific current density is about 0.7 A/mm, and the gate–drain breakdown voltage is 22–31 V for different versions.

The performance of a piecewise-stressed ZnO piezoelectric semiconductor nanofiber is studied with the multi-field coupling theory. The fields produced by equal and opposite forces as well as sinusoidally distributed forces are examined. Specific distributions of potential barriers, wells, and regions with effective polarization charges are found. The results are fundamental for the mechanical tuning on piezoelectric semiconductor devices and piezotronics.

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.