Journal of Electronic Materials最新文献

This paper reports a study of composite blends of polysulfone (PS) and polyvinylpyrrolidone (PVP) that were prepared in different wt% composition using carbon nanotubes (CNT), milled carbon fibers (MCF), graphene oxide (GO), and chopped carbon fibers (CCF) as nanofillers. The permeability measurements of the composites showed that the PS/PVP blends with different nanofillers demonstrated higher permeability for hydrogen gas than that of the pristine polymers, either singly or the polymer blend. The gases used for the permeation measurements were H₂, CO₂, N₂, O₂, and CH₄. Selectivity was calculated for H₂/CO₂, H₂/N₂, and H₂/CH₄ gas pairs. The results of the selectivity were plotted to show Robeson's 2008 upper bound and compared with reported data. The permeability of all gases increased for modified composite polymer membranes. We noted that O₂ gas solubility follows a trend similar to other gases, but gives a higher value than H₂ gas. The selectivity measurements showed that the MCF and CCF composite with the PS/PVP blend membranes demonstrated the highest selectivity for hydrogen gas among all different gas pairs. This indicates that PS/PVP composite membranes with MCF and CCF can be used for hydrogen purification and production of green hydrogen. There is a trade-off between permeability and selectivity parameters; GO and CNT nanofillers showed constant selectivity as permeability increased, which can be explained by the nanogap theory. The structural and morphological properties of these prepared composite membranes were characterized by field-emission scanning electron microscopy (FE-SEM), thermal properties by differential scanning calorimetry (DSC), and mechanical properties using a universal testing machine (UTM) for tensile strength, and Fourier transform infrared (FTIR) spectroscopy was carried out to identify the possible bond between polymers and nanofillers of the blend composite membranes. Blends modified with CNT, MCF, and GO exhibited increased viscosity, with an increase in the ∆b value at increasing concentrations, suggesting a favorable interaction between the phases. The water flux studies indicated that the highest pure water flux was obtained by the PS + PVP + CCF membrane. The highest rejection of Na₂SO₄ and of MgSO₄ was for the PS + PVP + CNT membrane.

Molybdenum disulfide (MoS₂) has been found to be a promising material for electronic and optoelectronic device applications due to its unique optical and electrical characteristics. However, the large-scale synthesis of MoS₂ thin films is limited by challenges in achieving reproducible and uniform device fabrication. In the present study, we utilized a sputtering technique and post-treatment by ion beam irradiation for large-scale fabrication of uniform MoS₂ thin films. The effects of the low-energy ion beam on the optical, structural, electrical transport, and morphological characteristics of the MoS₂ thin films were studied by Raman spectroscopy, atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, and electrical transport analysis. Tuning the electrical and optical characteristics of few- and monolayer MoS₂ through regulation of defects provides an excellent approach for fabricating two-dimensional (2D) MoS₂ thin films for electronic device applications. Thin film transistors (TFTs) have been widely studied for driving active-matrix displays given their promising electrical characteristics including significant on/off current ratio and mobility. In the present work, we report a back-gate MoS₂ TFT fabricated by sputtering. TFTs based on MoS₂ thin films were fabricated, and the current–voltage characteristics were studied at room temperature, which confirmed that the transport behavior differed between the pristine and ion-irradiated samples. Pristine MoS₂-based TFTs displayed significant Schottky barrier effects, resulting in lower mobility than ion-irradiated samples. Our comprehensive study focuses on the fundamental transport characteristics via the metal–MoS₂interface, which represents a substantial step towards achieving highly efficient electronic devices based on 2D semiconductors.

Channel thickness is a key parameter in determining the electrical characteristics of double-gate ZnO thin film transistors (DGTFTs). In thicker channels, the accumulation region is confined to the ZnO/SiO₂ (semiconductor/gate dielectric) interface. However, in such devices with ultrathin channels, the accumulation region extends the entire depth of the channel. This work investigates the impact of channel thickness on the electrical characteristics of a double-gate ZnO TFT in the grounded top gate (GTG) and common mode gate (CMG) biasing modes. Gaussian distributed traps are assumed to be present at the ZnO/SiO₂ interface with a peak concentration of 10¹² cm⁻² eV⁻¹ to accurately represent the interface. From technology computer-aided design simulations, it is concluded that in CMG mode, a bulk-accumulated 5-nm-thick DGTFT shows a 15- fold improvement in ON current as compared to its GTG counterpart. However, a 500-nm-thick DGTFT CMG mode shows merely twofold improvement in ON current compared to GTG mode.

In this study, radio frequency (RF) magnetron sputtering was used to deposit ZnO nanofilms and CuO nanorods. Firstly, the sputtering power was adjusted to study the structural porosity changes of ZnO. The oxygen flux and etching power were then adjusted to roughen the surface of the films to induce the optimal distribution of the CuO nanorods on the surface to increase its surface area for gas reaction. The ZnO film packaging process for gas sensing was also completed, mainly by a self-designed gas sensing circuit, at a lower work temperature of 100°C, to conduct sensitivity and response value analysis of CO gas sensing. In addition, X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) were used to analyze the crystallinity and morphology of ZnO, and high-resolution transmission electron microscopy (HRTEM) was used to analyze the interface microstructure of the ZnO/CuO nanorods. The absorbance of ZnO was measured by UV–Vis spectroscopy to indirectly verify the porosity. The results show that after depositing the ZnO film at 200 W, followed by roughening the surface with oxygen flux of 15 sccm and 100 W etching power for 10 min and then depositing the CuO nanorods for 10 s, the completed thin film structure had better CO sensing characteristics, and the highest response value was enhanced about 5% from 0.983 to 1.031. By optimizing the process parameters and incorporating the CuO nanorods, the sensing characteristics of the ZnO thin film were improved and a lower work temperature of 100°C for CO gas reaction was possible.

Four dyes with substitutions of carbazole and phenothiazine in position C4 of naphthalimide were designed in conjugation as a donor–acceptor architecture (D–A). The absorption and emission characteristics of the prepared dyes were investigated in H₂O, dimethylformamide (DMF), and their mixture (DMF:H₂O = 1:1). The prepared dyes exhibited a pink and yellow color, with strong emission at λ_em = 526–590 nm due to charge transfer, with a positive solvatochromic effect. The feasibility of electron transfer in the dye-sensitized solar cell (DSSC) structure and energy levels were evaluated using electrochemical and density functional theory (DFT), which confirmed the use of dyes in the DSSC structure. The DSSCs were prepared using an individual strategy, and their optical properties were investigated under light of AM 1.5. The DSSCs based on dyes 1–4 achieved efficiency of 4.37%, 4.59%, 4.11%, and 4.27%, respectively. Therefore, the power efficiency increased by about 39% in the presence of the phenothiazine group.

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Graphene has a large surface area, an open interconnect structure, and superior electrical conductivity, making it a promising material for high-performance supercapacitors. The appropriate choice of aqueous electrolyte is essential for its application as an electrode in a supercapacitor. The present study explores the supercapacitive behavior of graphene nanoplatelets in aqueous electrolytes that are acidic (H₂SO₄), alkaline (NaOH), and neutral (Na₂SO₄). Among these, H₂SO₄ delivers the maximum capacitance of 292 F/g, followed by NaOH and Na₂SO₄, with specific capacitance of 276 F g⁻¹ and 240 F g⁻¹, respectively, from cyclic charge–discharge at a current density of 0.3 A g^-1. Additionally, this electrode has maximum energy density and power density of 28 Wh kg⁻¹ and 270 W kg⁻¹, and it retains 90% of its capacity over 5000 cycles in H₂SO₄ electrolytes. An in-depth examination of supercapacitance is provided, along with an equivalent circuit simulation to deduce the behavior of the electrode–electrolyte interface.

Due to numerous characteristics (chemical stability, optical transparency, etc.), tissue equivalency, and other factors, lithium borates are an appropriate material for radiation dosimetry. This work explores the optical stimulated luminescence (OSL) dosimetry of lithium triborate (LiB₃O₅) doped with Ag. Here, we have used thermally-assisted OSL (TA-OSL), where OSL is recorded following thermal stimulation of the sample, to assess the presence of primary dosimetric and deep defects. The optimized elevated temperature for LiB₃O₅:Ag was found to be 100°C corresponding to maximum TA-OSL intensity due to depletion of its filled traps (indicating deep defects). X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), and ultraviolet–visible (UV-Vis) spectrophotometry were all used to characterized the structural and chemical properties of the sample. Along with other OSL characteristics like fading and repeatability, response of the obtained nanophosphor under CW-OSL with x-ray photons and electrons of a range of energies including cobalt-60 in radiotherapy has also been examined.

An exploration was undertaken to examine the physical and optical traits of a quaternary glass system utilizing tellurium dioxide as its primary component. The glasses were prepared with 60TeO₂-15B₂O₃-(25−x)Bi₂O₃-xSrCl₂ molar composition, where x = 5 mol.%, 10 mol.%, 15 mol.%, and 20 mol.%. The utilization of x-ray diffraction interpretation verified the amorphous nature of the glasses. Several physical properties were measured, including density (ρ), molar volume (V_m), and oxygen packing density (OPD). It was observed that the density decreased (from 5.301 g/cm³ to 3.542 g/cm³) as the heavier molar mass of bismuth(III) oxide was replaced with the lighter molar mass of strontium chloride. Consequently, the glass matrix became less dense. The molar volume increased (from 40.129 cm³/mol to 51.612 cm³/mol) with higher strontium chloride content. Adding strontium chloride decreased the OPD (from 56.069 to 34.875), reducing the number of oxygen atoms in the glass sample. The optical properties were analyzed via the ultraviolet absorption spectrum. The cutoff wavelength (λ_c) decreased (from 442 nm to 359 nm) as the strontium chloride content increased. With increased strontium chloride content, the prepared glasses showed indirect transitions in their energy band gaps. Additionally, the values of the indirect band gap energy (E_opt) increased from 2.02 eV to 2.95 eV. The Urbach energy (ΔE), which characterizes the disorder in the glass structure, decreased (from 0.288 eV to 0.270 eV) with increasing strontium chloride concentration, indicating a lower defect concentration. The molar refractivity values ranged from 26.82 to 31.79, reflecting the polarizability of the constituent ions. The glasses demonstrated a metallization criterion within the range of 0.332 to 0.384, indicating their promise for applications in the area of nonlinear optical devices.

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Spectra of optical absorption for the TBSr glasses.

For practical uses, there has been a lot of interest in simple, inexpensive, and efficient synthesis of materials for supercapacitor applications. Pure and cobalt-doped zinc sulfide (Co-doped ZnS) powder samples were synthesized in this study using a straightforward co-precipitation process, and their electrochemical performance was examined. It was observed that, at a scan rate of 10 mV s⁻¹, pure ZnS has a specific capacitance of only 460.7 F g⁻¹; however, the Co-doping in ZnS increases it to 947.8 F g⁻¹ for the 5% Co-doped sample, Co (0.05): ZnS. The results suggest that Co-doping in ZnS increases the kinetics and rate of redox processes. The increase in electrochemical active sites brought about by integrating Co into ZnS increases the surface area and results in the sample's capacity for storage. The encouraging findings increase the likelihood of elemental doping with other transition metal elements to increase the energy storage capability of earth-abundant ZnS samples.

Nitrogen dioxide (NO₂) emissions from numerous sources pose a significant threat to health, necessitating the development of highly sensitive electronic sensors. In response to this issue, this study investigates the influence of NO₂ molecules on a hydrogen (H)-passivated doped/undoped armchair graphene nanoribbon (ArGNR). The electronic properties are examined using density functional theory (DFT) within the framework of a linear combination of atomic orbitals (LCAO) calculator, combined with the nonequilibrium Green’s function (NEGF). The modeling focuses on the impact of doping with manganese (Mn) and co-doping of Mn with group V elements [nitrogen (N), phosphorus (P), and arsenic (As) atoms] on the electronic properties of the ArGNR. The introduction of the Mn element introduces spin–polarization that can influence the adsorption behavior of the target molecule, enhancing the sensitivity and selectivity of ArGNR. Moreover, the results show that the co-doping in ArGNR significantly enhances the bandgap opening compared to individual doping, resulting in improved sensitivity towards the NO₂ molecules. Subsequently, compared to Mn-P- and Mn-As-co-doped ArGNR, the Mn-N-co-doped ArGNR exhibits binding energy (E_B) of 308.47 eV, high chemisorption of −2.92 eV, desorption of 39.69%, notable variations in bandgap (E_G) of 16.5%, and a large current variation by a factor of 2.64 times following NO₂ adsorption, indicating improved conductivity. These findings highlight the potential of the Mn-N-co-doped ArGNR as a leading material for NO₂ sensing.

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