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Al₂O₃ used as gate dielectric enables exploitation of higher electric field capacity of SiC, improving capacitive coupling and memory retention in flash memories. Passivation of traps at interface and in bulk which causes serious threat is necessary for better performance. The purpose of this paper is to investigate the effect of post-deposition rapid thermal annealing (PDA) and post-metallization annealing (PMA) on the structural and electrical characteristics of Pd/Al2O3/6H-SiC capacitors.

Al₂O₃ film is deposited by ALD; PDA is performed by rapid thermal annealing (RTA) in N₂ at 900°C for 1 min and PMA in forming gas for 10 and 40 min. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements data are studied in addition to capacitance-voltage (C-V) and current-voltage (I-V) characteristics for the fabricated Pd/Al₂O₃/SiC capacitors. Conduction mechanism contributing to the gate leakage current is extracted for the entire range of gate electric field.

RTA forms aluminum silicide at the interface causing an increase in the density of the interface states and gate leakage current for devices with an annealed film, when compared with an as-deposited film. One order improvement in leakage current has been observed for the devices with RTA, after subjecting to PMA for 40 min, compared with those devices for which PMA was carried out for 10 min. Whereas, no improvement in leakage current has been observed for the devices on as-deposited film, even after subjecting to PMA for 40 min. Conduction mechanisms contributing to gate leakage current are extracted for the investigated Al₂O₃/SiC capacitors and are found to be trapfilled limit process at low-field regions; trapassisted tunneling in the mid-field regions and Fowler–Nordheim (FN) tunneling are dominating in high-field regions.

The effect of PDA and PMA on the structural and electrical characteristics of Pd/Al₂O₃/SiC capacitors suitable for flash memory applications is investigated in this paper.

We first provide an overview of some predominant theoretical methods currently used for predicting thermal conductivity of thin dielectric films: the equation of radiative transfer, the temperature‐dependent thermal conductivity theories based on the Callaway model, and the molecular dynamics simulation. This overview also highlights temporal and spatial scale issues by looking at a unified theory that bridges physical issues presented in the Fourier and Cattaneo models. This newly developed unified theory is the so‐called C‐ and F‐processes constitutive model. This model introduces the notion of a new dimensionless heat conduction model number, which is the ratio of the thermal conductivity of the fast heat carrier F‐processes to the total thermal conductivity comprised of both the fast heat carriers F‐processes and the slow heat carriers C‐processes. Illustrative numerical examples for prediction of thermal conductivity in thin films are primarily presented.

Natural convection in finite enclosures is a common phenomenon in various thermal applications. To provide the thermal design guidelines, this study aims to numerically explore the potential of using internal baffles and nanofluids to either enhance or suppress heat transport in a vertical annulus. Furthermore, the annular-shaped enclosure is filled with aqueous-silver nanofluid and the effects of five distinct nanoparticle shapes are examined. In addition, the influence of baffle design parameters, including baffle position, thickness and length, is thoroughly analyzed.

The finite difference method is used in conjunction with the alternating direction implicit and successive line over relaxation techniques to solve nonlinear and coupled partial differential equations. The single phase model is used for nanofluid which is considered as a homogeneous fluid with improved thermal properties. The independence tests are carried out for assessing the sufficiency of grid size and time step for obtaining results accurately.

The baffle dimension parameters and nanoparticle shape exhibit significant impact on the convective flow and heat transfer characteristics, leading to the following results: sphere- and blade-shaped nanoparticles demonstrate around 30% enhancement in the heat transport capability compared with platelet-shaped nanoparticles, which exhibit the least. When considering the baffle design parameter, either a decrease in the baffle length and thickness or an increase in baffle height leads to an improvement in heat transport rate. Consequently, a threefold increase in baffle height yields a 40% improvement in thermal performance.

Understanding the impact of nanoparticle shapes and baffle design parameters on flow and thermal behavior will enable engineers to provide valuable insight on thermal management and overall system efficiency. Therefore, the current work focuses on exploring buoyant nanofluid flow and thermal mechanism in a baffled annular-shaped enclosure. Specifically, an internal baffle that exhibits conductive heat transfer through it is considered, and the impact of baffle dimensions (thickness, length and position) on the fluid flow behavior and thermal characteristics is investigated. In addition, the current study also addresses the influence of five distinct nanoparticle shapes (e.g. spherical, cylindrical, platelet, blade and brick) on the flow and thermal behavior in the baffled annular geometry. In addition to deepening the understanding of nanofluid behavior in a baffled vertical annulus, the current study contributes to the ongoing advancements in thermal applications by providing certain guidelines to design application-specific enclosures.

The aim of the present work was the characterization of a group of compounds with the perovskite‐type structure in respect of their applicability as thermistor materials.

Four compositions: La_0.7Sr_0.3Zr_0.5Co_0.2²⁺Co_0.3³⁺O₃, La_0.8Sr_0.2Ti_0.5Co_0.3²⁺Co_0.2³⁺O₃, La_0.4Sr_0.6Ti_0.3Fe_0.7O₃ and CaTi_0.8Co_0.2O₃ were synthesized by solid‐state reaction. Ceramic thermistor materials were sintered in the temperature range 1,300‐1,400°C. The synthesized powders were used for fabrication of thick film pastes and thermistors fired at 1,100‐1,250°C. Resistance‐temperature characteristics of the ceramic samples were studied in the range −55 to 800°C for the ceramic samples and 20‐600°C for thick films. Endurance tests at 300°C for 500 h were performed.

The developed NTC materials exhibited high temperature coefficients of resistivity, dense microstructure and good stability. The most advantageous characteristics have been shown by La_0.7Sr_0.3Zr_0.5Co_0.2²⁺Co_0.3³⁺O₃ and La_0.8Sr_0.2Ti_0.5Co_0.3²⁺Co_0.2³⁺O₃ thermistors. The highest Temperature coefficient of resistances for the ceramics were found in the temperature range from −55 to 180°C (−10.7 to −2.9 per cent/°C) and for the thick films in the temperature range 40‐300°C (−5.6 to −1.5 per cent/°C).

This work has been focused on preliminary choice of compositions appropriate for practical thermistor thick film applications. Elucidation of conduction mechanism of the investigated materials needs further complex studies of conductivity, nonstoichiometry, thermoelectric power, etc. as a function of temperature and oxygen partial pressure.

In this work, an attempt has been made to extend the typical range of NTC compositions and to fulfil the demand for improved stability of bulk and thick film thermistors at elevated temperatures.

To give a new method to calculate the thermal conductivity of thin films which thickness is less than micro‐nanometer when non‐Fourier effect will appear in heat conduction and Fourier law is not applicable for calculating the thermal conductivity.

The Cattaneo equation based on the heat flow relaxation time approximation is used to calculate the thermal conductivity.

The results show that the thermal conductivity is not the thermophysical properties of material, but is the non‐linear function of temperature and film thickness when the dimension of film is less than micro‐nanometer.

The application of this method is limited by little experimental data of heat flow relaxation time for materials other than Ar crystals.

The paper demonstrates how the thermal conductivity of Ar crystals film can be calculated by NEMD algorithm and considers the non‐Fourier effect in the simulation.

The purpose of this paper is to study the effects of multi-walled carbon nanotubes (MWCNTs) loading on the thermal conductivity of nanocomposites.

In this paper, the polymer nanocomposite of MWCNT nanoparticles incorporated with PLA and LNR as compatibilizer were prepared via melt blending method.

The result has shown that the sample with 3.5 wt.% of MWCNT content provided higher thermal conductivity which is believed to be the optimum loading that formed the suitable percolated network for phonon conduction facilitation because of better dispersion in the PLA/LNR matrix as confirmed by SEM micrograph.

Thermal conductivity of polylactic acid (PLA)/liquid natural rubber (LNR) matrix improved with MWCNT.

This paper aims to consider numerical analysis of laminar double-diffusive natural convection inside a non-homogeneous closed medium composed of a saturated porous matrix and a clear binary fluid under spatial sinusoidal heating/cooling on one side wall and uniform salting.

The domain of interest is a partially square porous enclosure with sinusoidal wall heating and cooling. The fluid flow, heat and mass transfer dimensionless governing equations associated with the corresponding boundary conditions are discretized using the finite volume method. The resulting algebraic equations are solved by an in-house FORTRAN code and the SIMPLE algorithm to handle the non-linear character of conservation equations. The validity of the in-house FORTRAN code is checked by comparing the current results with previously published experimental and numerical works. The effect of the porous layer thickness, the spatial frequency of heating and cooling, the Darcy number, the Rayleigh number and the porous to fluid thermal conductivity ratio is analyzed.

The results demonstrate that for high values of the spatial frequency of heating and cooling (f = 7), temperature contours show periodic variations with positive and negative values providing higher temperature gradient near the thermally active wall. In this case, the temperature variation is mainly in the porous layer, while the temperature of the clear fluid region is practically the same as that imposed on the left vertical wall. This aspect can have a beneficial impact on thermal insulation. Besides, the porous to fluid thermal conductivity ratio, Rk, has practically no effect on Shhot wall, contrary to Nuinterface where a strong increase is observed as Rk is increased from 0.1 to 100, and much heat transfer from the hot wall to the clear fluid via the porous media is obtained.

The findings are useful for devices working on double-diffusive natural convection inside non-homogenous cavities.

The authors believe that the presented results are original and have not been published elsewhere.

Indium tin oxide (ITO) is a material belonging to the group of transparent conductive oxides, which are widely used in many fields of technology including optoelectronics and photovoltaics. However, the properties of ITO thin films depend on many factors. Therefore, the aim of the study was thorough investigation of the properties of sputtered ITO thin films of various thicknesses.

ITO coatings were deposited by magnetron sputtering in pure argon atmosphere using ceramic ITO target. Various deposition times resulted in obtaining thin films with different thickness, which had significant influence on the optoelectronic properties of deposited coatings. In this work the results of investigation of structural, surface, optical and electrical properties were presented.

Increase of the coating thickness caused change of the microstructure from amorphous to nanocrystalline and occurrence of grains with a size of 40 to 60 nm on their surface. Moreover, the fundamental absorption edge was red-shifted, whereas the average transmission in the visible wavelength range remained similar. Increase of the thickness caused considerable decrease of the sheet resistance and resistivity. It was found that even thin films with a thickness of 10 nm had antistatic properties.

The novelty and originality of presented work consists in, among other, determination of antistatic properties of ITO thin films with various sheet resistances that are in the range typical for dielectric and semiconducting material. To date, there are no reports on such investigations in the literature. Reported findings might be very helpful in the case of, for example, construction of transparent antireflective and antistatic multilayers.

The purpose of this paper is to investigate the effect of Mg²⁺substitution on the magnetic and electrical properties of Li_0.35−x Mg_2x Zn_0.3 Fe_2.35−xO₄ thick films synthesized with polyvinyl alcohol (PVA) matrix.

The nanoferrites Li_0.35−x Mg_2x Zn_0.3 Fe_2.35−xO₄ (x=0, 0.07, 0.14, 0.21, 0.28 and 0.35) were synthesized by chemical technique using aqueous solution of PVA (the matrix) and thick films were fabricated by screen printing technique. The DC magnetic hysteresis measurements, AC magnetic susceptibility and DC electrical resistivity were measured as a function of temperature.

The lattice parameter of thick film Li_0.35−x Mg_2x Zn_0.3 Fe_2.35−xO₄ (x=0, 0.07, 0.14, 0.21, 0.28 and 0.35) increases with the substitution of Mg²⁺ions for Li¹⁺and Fe³⁺. The surface morphology of the thick films showed the grain size increasing with Mg²⁺substitution till x=0.21 and then decreasing for the higher concentrations of magnesium. The magnetic moment n_B (μ_B) computed from the M_s obtained by extrapolation of the magnetization curve showed a gradual decrease with the composition till x=0.21, beyond which a sudden decrease was observed. The resistivity of the films at room temperature had variation with composition x, similar to that of magnetic moment. The activation energies ΔE_F and ΔE_P were found to vary with composition x of the ferrite system.

The paper reports, for the first time, the magnetic and electrical properties of fritless Li_0.35−xMg_2xZn_0.3Fe_2.35−xO₄ thick films using PVA polymer matrix. Up to x=0.21 (Mg²⁺), grain size increases and Curie temperature decreases beyond which reverse effect takes place.