Journal of Electronic Materials最新文献

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.

Graphical Abstract

In this work, nickel thin film with thickness of 35 nm was grown by radio frequency sputtering on a Si/SiO₂ substrate as a function of growth temperature from 100°C to 350°C. The effect of substrate temperature during film growth was extensively investigated with regard to the structural, morphological, and dynamic magnetic properties of the grown films. The films were polycrystalline with a face-centered cubic (FCC) structure, as evident from the different diffraction peaks. The saturation magnetization (M_S) was greatest and coercivity (H_C) was observed to be lowest for films grown at 250°C. The Gilbert damping (({alpha }_{{rm eff}})) and effective magnetization (({M}_{{rm eff}})) as a function of growth temperature were obtained from microwave-induced ferromagnetic resonance (FMR) spectroscopy measurements. ({alpha }_{{rm eff}}) derived from FMR line widths, which is an important parameter for quantifying ferromagnetic film quality, was lowest at 250°C and increased on either side of this point. The lowest damping at 250°C indicates low strain and defect density at this temperature, which is also evident from x-ray diffraction (XRD) data. ({M}_{{rm eff}}) also increased and reached a maximum at 250°C growth temperature. The decrease in magnetization below and above 250°C indicates diffusion and formation of a magnetic dead layer at the substrate–film interface. These measurements reveal that a narrow growth temperature regime exists for the growth of Ni thin film to obtain films with low defects, and hence low Gilbert damping, which can be utilized in spintronics device applications.

We performed first-principles calculations to investigate the structural, electronic, magnetic, optical, and thermoelectric properties of Mn₃Si₂Te₆ (MST) at various temperatures using the BoltzTraP package. From the experimental analysis, the material exhibited a metallic nature due to zero bandgap. After performing density functional theory calculations by applying strain engineering on the MST compound, we discovered that the material was a half-metal. The thermoelectric characteristics of the MST compound under strain engineering were investigated using WIEN2k code. The results demonstrated that at 5% tensile strain engineering, the material was half-metal, with an indirect bandgap of 0.732 eV at the Γ–K symmetry point of the Brillouin zone with the generalized gradient approximation (GGA). It was discovered that compressive strain reduced the bandgap whereas tensile strain increased the bandgap value of the bulk MST. With the use of the hybrid functional (GGA + modified Becke–Johnson [mBJ] potential) at 4% tensile strain, the highest bandgap of 1.24 eV at Γ–K was obtained. The optical characteristics at 4% tensile strain were calculated with the hybrid functional. Finally, the thermoelectric properties of MST were determined, including the Seebeck coefficient, electrical conductivity, thermal conductivity, power factor, and figure of merit at 4% tensile strain from 300 K to 800 K. It was found that the Seebeck coefficient and electrical conductivity of MST are temperature-sensitive and decrease as the temperature rises. The Seebeck coefficient was measured at a temperature of 300 K for 4% strain, obtaining values of 300 µV/K (p-type) and 310 µV/K (n-type) region. The lattice thermal conductivity (LTC) was calculated with increasing temperature for MST from 8 W/mK at 100 K to 2 W/mK at 600 K, for 0–10 GPa. The calculated dimensionless figure of merit, ZT, at 300 K reached 0.72 for both p- and n-type, which decreased to 0.56 with experimental thermal conductivity. These results indicate that MST could be suitable material for use in future thermoelectric devices.

Potassium calcium sulfate (K₂Ca₂(SO₄)₃:Eu,Cu) co-doped with Eu²⁺ and Cu²⁺ (1000 ppm each) has been prepared by the co-precipitation method. Compound confirmation was carried out by X ray diffraction, and the average crystallite size was 61 nm, calculated by the Williamson–Hall plot method. The presence of dopants was confirmed by the photoluminescence emissions and excitation spectra. This nano-crystalline phosphor has been investigated for its dosimetric applications by studying its thermoluminescence (TL) properties after being irradiated with ion beams (C⁶⁺) at different fluences of different energies (65 MeV, 75 MeV, and 85 MeV). Also, the co-doped phosphor was compared with the singly-doped K₂Ca₂(SO₄)₃:Eu in terms of its TL intensities, and it showed a higher TL sensitivity. Moreover, it showed a good dose response only for a low-energy C⁶⁺ ion beam.

A poly(methylmethacrylate)-based Mg-ion conducting polymer gel electrolyte immobilizing a liquid electrolyte of magnesium perchlorate in tetraethylene glycol dimethyl ether (TEGDME) solvent is presented. In order to enhance the electrolytic properties of the electrolyte, the impact of aluminum oxide (Al₂O₃) nanoparticles on the structural, thermal, and electrochemical properties has been investigated. The optimized composition of the polymer gel electrolyte (PMMA + TEGDME + MgClO₄ + 2.5 wt% Al₂O₃) showed increased ionic conductivity of 4.94 × 10⁻⁵ S cm⁻¹ with a significantly low activation energy of 0.18 eV. Ion dynamics in the polymer gel electrolyte have been quantitatively analyzed by investigating various frequency-dependent parameters such as the real and imaginary components of dielectric permittivity, loss tangent, and the modulus. The possible conformational changes in the electrolyte system on addition of Al₂O₃ nanoparticles have been investigated by x-ray diffraction (XRD), Fourier-transform infrared (FTIR) analysis, and differential scanning calorimetry (DSC). These studies have revealed CH₃-Mg-Al₂O₃ interaction in the electrolyte with significantly affected crystallinity and sufficient gel phase range with variation in temperature.

Recent advances in ultrasensitive electrical biosensors using graphene nanostructures such as nanowalls and nanopores have increased the surface area-to-volume ratio. These structures provide signals at low biomolecule concentrations that are generally insufficient for vital measurements, especially in complex physiological analytes, making practical deployment difficult. A new, reproducible, and scalable chemical technique for constructing smooth graphene nanogrids enables molar biomolecule detection in field-effect transistor (FET) mode. We examine how pore morphology affects the sensing capability of label-free graphene nanoporous FET biosensors, aiming for sub-femtomolar detection limits with a good signal-to-noise ratio (SNR) in blood or urine serum. Despite problems including drain–source current sensitivity overlap due to high quantities of nonspecific antigens, our improved graphene nanogrid sensor detected hepatitis B (Hep-B) surface antigen in serum at sub-femtomolar levels. In serum containing 3 nM hepatitis C (Hep-C) as a nonspecific antigen, a pore diameter of 30 nm and length of 120 nm had the highest SNR and detected 0.25 fM Hep-B. We used a graphene nanogrid FET biosensor in heterodyne mode (80 kHz to 2 MHz) to quantify Hep-B down to 0.3 fM in blood using a probabilistic neural network (PNN) to reduce Debye screening effects. The performance of the PNN exceeded that of the polynomial fit and static neural network models by limiting quantification errors to 10%. Electrical resistance was linearly related to the Hep-C virus core antigen (HCVcAg) concentration (80–550 pg/mL) in real-time tests. After improvement of functionalization parameters, the SNR increased 70%, detecting 0.20 fM Hep-B virus molecules with 60% sensitivity and 6% standard deviation.

In this work, based on first-principles calculations and Boltzmann transport theory, we have investigated the structural, electronic, mechanical, and thermoelectric properties of (hbox {CdSbS}_{3}) and (hbox {CdSbSe}_{3}) compounds, which are two novel members of the (hbox {MAX}_{3}) family. We found that these compounds are semiconductors with a narrow band gap. In addition, they are both mechanically, dynamically, and thermodynamically stable. The results show that their interlayer distances are wider than almost all transition metal dichalcogenide compounds. Furthermore, we report that the lattice thermal conductivity,(kappa _{text{l}}), at room temperature for (hbox {CdSbS}_{3}) is 0.53 W m⁻¹ K⁻¹ and 0.13 W m⁻¹ K⁻¹ for (hbox {CdSbSe}_{3}). This latter value is similar to that of (hbox {ZnPSe}_{3}), which was found to be lower than all other 2D materials. More remarkably, the thermoelectric figure of merit of (hbox {CdSbS}_{3}) reaches as high as 2.34 at 1400 K and 2.68 for (hbox {CdSbSe}_{3}) at 850 K, which is a record high value at this temperature.

Thin films of polyaniline/polyvinyl chloride (PANI/PVC) composites synthesized and irradiated with a nickel ion (Ni⁷⁺) beam using flux of 3.125(times)10⁹ particles/cm²/s and fluence ranging between 3(times)10¹¹ and 1(times)10¹³ particles/cm² were investigated with respect to their optical, structural, and electrical properties. The photoluminescence (PL) analysis showed that swift heavy ion (SHI) irradiation caused the creation of new color centers, which were diminished at greater fluence. With irradiation, both the direct and indirect band gaps decreased, making the materials more conducive to conduction. However, the direct band gap was smaller than the indirect band gap. Fourier transform infrared (FTIR) analysis showed that the aromatic nature of PANI was not disturbed by SHI irradiation. The variation in capacitance with frequency indicated that the material can be used for electromagnetic interference (EMI) shielding, and the shielding properties are modified by ion irradiation. Scanning electron microscopy (SEM) analysis revealed that irradiation of the polymer with Ni⁷⁺ leads to chain scissoring and cluster formation, whereas at higher fluence, smaller parts are rearranged to form micro-clusters.

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Developing affordable thermoelectric (TE) materials is critical for efficient waste heat recovery in industries. With the goal of developing novel, affordable TE materials, the present experimental–theoretical investigation, for the first time, presents a rigorous analysis of the electrical and thermal transport properties of a multi-principal-component AlCuFeMn alloy (MPCA). TE properties related to electronic transport, including the Seebeck coefficient, electrical conductivity, and thermal conductivity, were measured on a vacuum-cast sample and were computed using semi-classical Boltzmann transport theory. Additionally, ab initio calculations were performed to calculate the lattice thermal conductivity. The alloy demonstrated overall thermal conductivity of < 4 W/mK, comparable to conventional thermoelectric materials, while the computed lattice thermal conductivity was < 1 W/mK. Such low thermal conductivity may be attributed to the complex microstructure as well as the uniform distribution of aluminium in the matrix. The power factor of the alloy, however, was small (< 0.1 mW/mK²), translating to a low figure of merit (ZT ~ 0.01). Our study indicates that composition engineering can potentially improve the power factor and thus the overall TE response in an AlCuFeMn alloy.

Graphical Abstract