Applications In Electronic Devices Research Articles

Interface analysis of oxide free MoS2 films fabricated by solution process.

We report a solution-based approach for the synthesis of oxidation-free MoS2 films, focusing on interface analysis. Through a sulfurization-free solution process and single-step annealing, the oxidation-free MoS2 film is successfully prepared on Si3N4 surfaces, showing improved uniformity with a surface roughness below 0.5nm and a thickness of 4nm at a precursor solution concentration of 30 mM, annealed between 700 and 800ºC. The MoS2 films exhibit a hexagonal lattice structure with crystallographic orientations of (1 1 0 0) and (1 2 1 0) with lattice spacings of 0.27nm and 0.16nm respectively. Interfacial analysis by X-ray photoelectron spectroscopy (XPS) on SiO2 reveals migration of oxygen species as evidenced by a shift in the Si 2p spectrum at binding energies between 102.6eV and 102.8eV. MoS2 films on Si3N4 show a complex Si 2p peak evolution at binding energies between 100.9 and 101.8eV, providing valuable insights into the synthesis of oxide-free MoS2 films for potential applications in advanced electronic devices.

Tungsten interior doping engineering induced sulfur vacancies of MoS2 for efficient charge transfer and nonlinear optical performance: Implications for optical limiting devices

Modulating the photoelectric properties of molybdenum disulfide (MoS2) through defect engineering and heterometal doping is crucial for its potential applications in electronic and optoelectronic devices. Herein, a comprehensive overview is provided on the advancements of two-dimensional materials with a ternary structure comprising sulfur (S), molybdenum (Mo), and tungsten (W) in the field of optoelectronic device. A ternary W-P/MoS2 (P: direct current target power) nanomaterial was designed and synthesized using W interior doping engineering induced S vacancies. The experimental results reveal that the introduction of W metal causes lattice distortion in MoS2, leading to the formation of S vacancies within W-P/MoS2. Compared to pure MoS2, W-P/MoS2 with S vacancies demonstrates enhanced reverse saturable absorption and optical limiting. Density functional theory calculations suggest that the S vacancies introduced by W doping in MoS2 introduce defect energy levels, which are believed to be the reason for the improved nonlinear optical (NLO) performance of W-P/MoS2. Furthermore, transient absorption spectroscopy reveals the photophysical model of carrier relaxation and presents an explanation for the optimized NLO properties of W-P/MoS2. This work provides a novel strategy for the design and synthesis of ternary transition metal dichalcogenides and modulating the NLO properties by doping transition metal-mediated vacancies.

Super-Tough, Non-Swelling Zwitterionic Hydrogel Sensor Based on the Hofmeister Effect for Potential Motion Monitoring of Marine Animals.

Hydrogel-based electronic devices in aquatic environments have sparked widespread research interest. Nevertheless, the challenge of developing hydrogel electronics underwater has not been profoundly surmounted because of the fragility and swelling of hydrogels in aquatic environments. In this work, a zwitterionic double network hydrogel comprisedof polyvinyl alcohol (PVA), poly(sulfobetaine methacrylate) (PSBMA), and sulfuric acid (H2SO4) demonstrates super-tough and non-swelling performance. The Hofmeister effect of H2SO4 and PSBMA induces the PVA chains to form numerous nanocrystalline domains, which serve as the primary physical crosslinking points and provide effective energy dissipation. H2SO4 induces a strong salting-out effect to facilitate PVA crystallization and the formation of a dense and stable network structure that inhibits swelling. The resulting hydrogel exhibits an ultra-high toughness of 4.61MJm-3, non-swelling, and long-term stability for up to a month in pure water and seawater. Based on this, a hydrogel-based seawater strain sensor has been developed to monitor the underwater movements of marine animal models. Reliable and stable sensing performance ensures real-time collection of underwater motion signals, despite the impacts of water flow and the interference of ions. This study provides a facile approach to designing super-tough and non-swelling hydrogels and further expands the application of underwater electronic devices.

Van der Waals GeSe with Strain- and Gate-Tunable Linear Dichroism for Wearable Electronics.

The direct detection of light polarization poses a crucial challenge in the field of optoelectronics and photonics. Herein, the tunable linear dichroism (LD) in GeSe-based polarized photodetectors is presented through electronic and structural asymmetry modulation, and demonstrate their application prospects in wearable electronics. An improvement in the dichroic ratio up to 34% is achieved under a gate voltage of 20V, and the improvement reaches 44% by applying a tensile strain along the zigzag direction. Theoretical calculations reveal that the gate regulation of barrier height between GeSe and Au electrodes is responsible for the electrical-tunable LD, while the anisotropic optical absorption in response to strains leads to the strain-tunable LD. Moreover, flexible GeSe transistors are developed for wearable applications including motion sensors and glucose monitors. This study offers viable approaches for modulating the optical anisotropy of low-dimensional materials and emphasizes the versatility of van der Waals materials for practical applications in wearable electronic devices.

Controlled Distribution of MXene on the Pore Walls of Polyarylene Ether Nitrile Porous Films for Absorption-Dominated Electromagnetic Interference Shielding Materials.

With the increasing application of electronic devices, absorption-dominated electromagnetic interference shielding materials (EMISM) have garnered significant attention for preventing secondary electromagnetic pollution. In this study, polyethyleneimine (PEI)-modified MXene (PEI@MXene) is fabricated and achieved its controlled distribution on the pore walls of polyarylene ether nitrile (PEN) porous films via the phase inversion method (PIM) to obtain a closed porous skeleton of MXene on the pore walls (CPS-MPW). The resulting PEI@MXene/PEN composite film (CFx) exhibited absorption-dominated EMIS efficiency (EMISE). Attributing to the strong interaction between PEI and the hydrophilic segment of amphiphilic Pluronic F127, with its hydrophobic segment anchored by the PEN matrix, PEI@MXene is directionally distributed on the pore walls of CFx. In addition, resulting from the cladding of MXene with PEI and isolating it with closed honeycomb pores, the obtained CFx are insulators without forming aconductive network. As a result, these CFx demonstrate absorption-dominated EMISE with the highest SET of 41.2 dB and coefficient A higher than 0.51. Further continuous hot pressing of CFx results in thinner and denser films with an impressive specific EMISE up to 750 dBcm-1. The successful fabrication of these CPS-MPW-type CFx with absorption-dominated EMISE provides a reference for developing and preparing novel EMISM.

Novel insights into PLMN-13PT ceramics: impact of spark plasma sintering on compositional and dielectric properties

AbstractThis study investigates the effects of Spark Plasma Sintering (SPS) on the physical, structural, microstructural, dielectric, and optical properties of on 87[Pb(1−y)Laₓ(Mg1/3Nb2/3)O3]-13PbTiO3, (PLMN-13PT) ceramics. The primary objective was to evaluate how SPS influences the densification, grain growth, and compositional variations of these ceramics, which are critical for electronic device applications. The results demonstrate that SPS effectively achieves high relative density while suppressing grain growth, leading to a more homogeneous microstructure. However, the rapid densification process also induces compositional variations that significantly impact the dielectric properties, including the reduction of undesirable phases like pyrochlore, which are detrimental to performance. These findings highlight the potential of SPS for optimizing PLMN-13PT ceramics, enhancing their suitability for the miniaturization of multifunctional electronic devices.

Design of 2.45 GHz rectenna based on high-gain 2-element array antenna and 7-stage voltage-doubler rectifier for energy harvesting applications

Abstract This paper proposes a new design of a 2.45 GHz compact rectenna for ambient RF energy harvesting, presenting a complete energy harvesting system. The proposed rectenna design features a two-element antenna array with high gain and a novel voltage-doubler configuration. The two-element antenna array is fabricated on Rogers RT/Duroid-5880 substrate, utilizing a rectangular microstrip patch antenna fed by a symmetric 50 Ω coplanar line. The antenna’s performance is tested numerically and experimentally in terms of return loss (S11) and radiation patterns. The results show excellent matching bandwidth at 2.45 GHz with a high gain of 7.03 dBi, providing a reasonable agreement between measurement and simulation results. The rectenna design employs a 7-stage voltage doubler rectifier that generates a dynamic DC voltage and improves the circuit’s reliability and performance. The receiving antenna and the rectifier are connected via a single L-section, comprising a shunt capacitor and a series inductor, for impedance matching, resulting in size reduction. The rectifier exhibits a peak simulated power conversion efficiency (PCE) of 75% and a measured efficiency of 60% at an input power of 20 dBm. The rectenna yields a high output DC voltage of 4.9 V at an input power of 13 dBm with a resistive load of 1 kΩ. These results reveal that the proposed 2.45 GHz rectenna is a suitable candidate for RF energy harvesting applications in low-power sensors and electronic devices.

Deriving 2D in-plane heterostructures in TMDC nanosheets via electron beam irradiation

2D in-plane heterostructures can enhance the electronic performance of hybrid systems, allowing for a variety of electronic device applications. However, precisely achieving uniform in-plane heterostructures with seamless interfaces at the same atomic planes remains a challenge. In this work, 2D in-plane heterostructures were successfully fabricated through electron beam irradiation-induced phase transformation in transition metal dichalcogenides (TMDCs). The transformed phases were seamlessly connected to the pristine TMDCs, forming ultraclean and atomically sharp interfaces of heterostructures. The phases were stable and determined to be novel tetragonal-like atomic structures by experimental and theoretical analyses. In situ transmission electron microscopy revealed that the phase transition involved atomic loss, lattice contraction, and then significant structural reconstruction in the pristine TMDCs. These results demonstrate that electron irradiation can efficiently achieve precise manufacturing of 2D in-plane heterostructures, offering new opportunities for the development of high-quality 2D in-plane heterostructures and novel 2D devices with high performance.

Atomic Fabrication of 2D Materials Using Electron Beams Inside an Electron Microscope.

Two-dimensional (2D) materials have garnered increasing attention due to their unusual properties and significant potential applications in electronic devices. However, the performance of these devices is closely related to the atomic structure of the material, which can be influenced through manipulation and fabrication at the atomic scale. Transmission electron microscopes (TEMs) and scanning TEMs (STEMs) provide an attractive platform for investigating atomic fabrication due to their ability to trigger and monitor structural evolution at the atomic scale using electron beams. Furthermore, the accuracy and consistency of atomic fabrication can be enhanced with an automated approach. In this paper, we briefly introduce the effect of electron beam irradiation and then discuss the atomic structure evolution that it can induced. Subsequently, the use of electron beams for achieving desired structures and patterns in a controllable manner is reviewed. Finally, the challenges and opportunities of atomic fabrication on 2D materials inside an electron microscope are discussed.

Iron phosphides nanoparticles strongly coupled to N-doped carbon for high-efficiency oxygen reduction and evolution

Constructing composite structures is an effective strategy for tailoring the electronic configuration and balances the adsorption/desorption capability of oxygen-containing intermediates for obtaining high-performance bifunctional catalysts. Herein, an in-situ pyrolysis strategy was used to construct Fe2P nanoparticles supported on N-doped carbon (Fe2P/NC) catalyst. The DFT indicated that the catalytic activity of the as-prepared catalyst is significantly increased by the strong electronic interaction between the Fe2P nanoparticles and the nitrogen-doped carbon, which endows the catalyst with fast electron transfer capability and optimizes the free energy between the catalyst and the adsorbed intermediate, as well as the d-band center of the material. The as-synthesized Fe2P/NC has a low potential gap ΔE (ΔE = Ej=10 – E1/2) of ca. 0.75 V, a specific capacity as high as 833 mAh·gZn−1 and cycling stability for 1320 cycles at the current density of 10 mA·cm−2. Such a synthesis strategy provides an effective route to realizing applications for portable electronic Zn-air battery-related devices.

Carbon nanostructures for high-frequency line-filtering supercapacitors

Supercapacitors (SCs) are considered one of the front-runner energy storage devices for future electronic and automobile device applications. Even though their high-power densities, fast charge/discharge, and long cycling stabilities make them promising for future applications, their charge-discharge takes place below 1 Hz, a major issue for using them as capacitors for line filtering applications. Therefore, developing ultrafast electrochemical supercapacitors with alternating current (AC) line filtering functions has gained research attention to replace conventional aluminum electrolytic capacitors (AEC). Most available SCs possess resistive features rather than capacitive at 120 Hz because of the electrode geometry and configurations, which is a bottleneck in the research of line-filtering SCs. Addressing this challenge could be possible by developing novel electrode materials using hybrid nanostructures to meet the critical requirements for line filtering functions. This mini-review focuses on the advancement and challenges of carbon nanostructure-based electrode materials for AC line filtering applications and the future directions of this growing research area.

One-pot preparation of strong, tough, frost-resistant and recyclable organohydrogels via Hofmeister effect and its application for electronic devices

Conductive hydrogels have shown a great potential in the field of flexible electronics. However, it is difficult to combine high strength and high toughness in conductive hydrogels prepared by conventional methods, which limits their applications in various fields. In this work, we pioneered a facile and cost-effective strategy to prepare soy protein isolate/poly(vinyl alcohol) (SPI/PVA) conductive hydrogels with high strength, toughness, low-temperature resistance, and recyclability by introducing all the salts into the prescuor solution directly. To solve the problem of unable to directly introducing high concentration Na3Cit into the soy protein isolate/PVA solution, MgCl2 was used to alleviate the strong salting-out effect of Na3Cit. Thus the stable SPI/PVA/EG/MgCl2/Na3Cit complex solution was obtained and the SPI/PVA/EG/MgCl2/Na3Cit (SPEMS) organohydrogel was prepared by the freezing/thawing process. The optimum tensile strength of the SPEMS organohydrogel was 1.1±0.07 MPa, and the elongation at break was 701.3±23.67 %, respectively. Meanwhile, the ionic conductivity of the organohydrogel was as high as 1.7±0.01 S/m. Finally, the EG/H2O binary solvent system endowed the organohydrogel with excellent low-temperature resistance (freezing point of −19.4 °C). The strain sensors assembled with SPEMS organohydrogels were characterized by high sensitivity (GF = 3.2, strain range from 20 %–500 %) and long-term stability. The flexible all-solid-state supercapacitor assembled with SPEMS organohydrogel as the electrolyte and activated carbon as the electrodes has a high area specific capacitance (113.76 mF/cm2) and good cycling stability (capacitance retention of 81.62 % after 1,000 charging and discharging cycles) at room temperature.

Supercritical CO2-Guided Passivation Strategies for Oxygen Vacancy Modulation in LaMnO3.

The development of 2D magnetic materials and the modulation of intrinsic magnetism are essential for the exploration of new materials in the field of information storage. Despite its strong ferromagnetic properties, LaMnO3 is hindered by a high number of oxygen defects, which result in a relatively short lifetime when employed in electronic memory devices. Here the successful transformation of bulk LaMnO3 into a 2D structure using supercritical carbon dioxide.is reported. This technique enables the successful modulation of the magnetic properties of the material. Interestingly, it is found that the oxygen defect is repaired, which is in sharp contrast to conventional perovskites. These promising results demonstrate the potential of using the magnetic properties of LaMnO3, which is of great importance in the context of expanding its application in electronic devices.

Charged Impurity Scattering and Electron-Electron Interactions in Large-Area Hydrogen Intercalated Bilayer Graphene.

Intercalation is a promising technique to modify the structural and electronic properties of 2D materials on the wafer scale for future electronic device applications. Yet, few reports to date demonstrate 2D intercalation as a viable technique on this scale. Spurred by recent demonstrations of mm-scale sensors, we use hydrogen intercalated quasi-freestanding bilayer graphene (hQBG) grown on 6H-SiC(0001), to understand the electronic properties of a large-area (16 mm2) device. To do this, we first analyze Shubnikov-de Haas (SdH) oscillations and weak localization, permitting determination of the Fermi level, cyclotron effective mass, and quantum scattering time. Our transport results indicate that at low temperature, scattering in hQBG is dominated by charged impurities and electron-electron interactions. Using low- temperature scanning tunneling microscopy and spectroscopy (STS), we investigate the source of the charged impurities on the nm-scale via observation of Friedel oscillations. Comparison to theory suggests that the Friedel oscillations we observe are caused by hydrogen vacancies underneath the hQBG. Furthermore, STS measurements demonstrate that hydrogen vacancies in the hQBG have an extremely localized effect on the local density of states, such that the Fermi level of the hQBG is only affected directly above the location of the defect. Hence, we find that the calculated Fermi level from SdH oscillations on the millimeter scale agrees with the value measured locally on the nanometer scale with STS measurements.

Noncoordinating Anions as Key Modulators of Supramolecular Structures, Optical and Electrical Properties in Nickel(II) Complexes.

This study explores the synthesis, structural characterization, and examination of two nickel(II) complexes, [Ni(N 3 L 1 )2](NO3)2 (complex 1) and [Ni(N 3 L 1 )2](ClO4)2 (complex 2), using the newly synthesized organic heterocyclic chelating ligand N 3 L 1 [4-imidazole-2,6-di(pyrazinyl)pyridine]. Through single-crystal X-ray diffraction, we have detailed the crystal structures of these complexes, highlighting their distorted octahedral geometries and diverse supramolecular interactions including π···π stacking, anion···π, and hydrogen bonding. These interactions crucially influence the formation of distinct one- and two-dimensional supramolecular architectures. Density functional theory (DFT) calculations were utilized to probe these noncovalent interactions, revealing insights into their stereoelectronic influence and stability in the solid state. Additionally, the electronic properties of the complexes were explored through their electrical characterizations in Schottky diodes, which suggest the potential of these complexes in Schottky diode based electronic devices applications. Notably, complex 2, incorporating perchlorate anions, exhibited better electrical properties than complex 1. This work aims to elucidate the role of noncoordinating counteranions in the structural integrity and photophysical behavior of these complexes, while also providing a structure-function correlation through detailed theoretical analysis.

Atomic and electronic structures of the [formula omitted]-FeSi2/Si(001) interface

The atomistic interface structure between β-FeSi2 and Si substrate was investigated by cross-sectional scanning transmission electron microscopy and density functional theory calculations (DFT). A high quality single crystalline β-FeSi2 film was epitaxially grown on Si(001) substrate. We demonstrate that the β-FeSi2(100) plane is bonded to the Si(001) plane with two Si dimers per unit cell. With such interface structure, DFT band calculations reveal that metallic electronic states are localized at the interface. This finding implies the presence of two dimensional electronic states at the interface of β-FeSi2/Si(001), which may have potential applications in silicon-based electronic devices.

Vertical stacking approach for tailoring electronic and optical properties of ultrathin two-dimensional vdW heterostructures of P-MAB (M=Ti, Zr, Hf; A=S, B=Se)

The vertical stacking in the form of heterostructures, is an effective way to enhance the performance of corresponding isolated monolayers. Strong interactions between Janus monolayers (MAB) and Phosphorus (P) monolayers result in significant improvements in both physical and chemical properties compared to single layer configurations. Using first-principle (hybrid) calculations, we explore electronic structure and optical properties of P–MAB (M = Ti, Zr, Hf; A = S, B=Se) van der Waals heterostructures, for potential applications in electronic and optoelectronic devices. Ab initio molecular dynamic (AIMD) simulations confirm the thermal stability, while phonon spectra confirm the dynamical stabilities of these systems. Our analysis reveals that all configurations maintain semiconducting nature with an indirect bandgap. The type-II band alignment in the P–MAB heterostructures is demonstrated through calculations of the partial density of states (PDOS). Bader charge analysis and planar-averaged charge density differences indicate an electron transfer from the P monolayers to the MAB monolayer. Furthermore, our investigation of the dielectric function ϵ2(ω) shows that the lowest energy shift are primarily influenced by excitonic effects.

Investigation of high-detectivity self-powered photodetectors of Rubrene/Bi2Se3 hybrid Van der Waals heterojunction

This paper investigates the Vander Waals heterostructure of organic rubrene and topological insulator Bi2Se3 with an atomically abrupt interface with exciting applications in electronic and optoelectronic devices. This organic/inorganic heterostructure (OIH) was prepared using a simple two-step physical vapor deposition process; based on this hybrid structure, a self-powered photodetector was then constructed. The Dirac surface state at the heterointerface enhances the splitting and transferring of photo-generated carriers, resulting in improved device characteristics. Under 1064 nm, the prepared photodetectors demonstrated a maximum responsivity (6.37 A/W), a high detectivity (3.42 × 1010 Jones), and ultrafast photoresponse speeds with rise time (1.17 µs) and decay time (1.59 µs), respectively. These promising results suggest that these PDs can be used in various photodetection applications and may lead to developing new devices.

Modelling of Cut-off Frequency of Armchair Graphene Nanoribbon Tunnel Field Effect Transistor Using Transfer Matrix Method

Graphene is considered as a promising two-dimensional material for electronic device applications due to its high charge carrier mobility and it is extremely thin in size. As a material, graphene has great potential for the development of high-speed nano electric devices. Graphene can be used as a channel material in Tunnel Field Effect Transistor (TFET). In this study, the cut-off frequency of the armchair graphene nanoribbon tunnel field effect transistor (AGNR-TFET) device was modelled quantum mechanically. The solution of the Dirac-like Hamiltonian and Poisson equations self-consistently is used to determine the potential profile of device and the transmittance is calculated using the transfer matrix method (TMM). The Landauer formulation with the help of Gauss Legendre Quadrature Method (GLQM) is used to calculate the tunnelling current and the cut-off frequency of AGNR-TFET. The calculation results showed that the cut-off frequency increased as the drain voltage increased, while the increase in channel length and the N-index graphene made the cut-off frequency decreased. Moreover, the thicker the oxide layer could increase the cut-off frequency and the higher the temperature on the device would reduce the cut-off frequency.

Manipulation of Supramolecular Chirality in Bicontinuous Networks of Bent-Shaped Polycatenar Dimers.

Bicontinuous cubic liquid crystalline (LC) phases are of particular interest due their possible applications in electronic devices and special supramolecular chirality. Herein, we report the design and synthesis of first examples of achiral bent-shaped polycatenar dimers, capable of displaying mirror symmetry breaking in their cubic and isotropic liquid phases. The molecules have a taper-shaped 3,4,5-trialkoxybenzoate segment connected to rod-like building unit terminated with one terminal flexible chain. The two segments were connected using an aliphatic spacer with seven methylene units to induce bending of the whole structure. Investigated by the small-angle X-ray scattering (SAXS), a double network achiral cubic phase Cub/Ia d, which is a meso-structure, and a chiral triple network cubic phase Cub/I23[*] are formed. The molecules self-assemble into molecular helices and progress along the networks. Interestingly, different linking groups such as ester or azo linkages and core fluorination lead to distinct local helicity, resulting in an alkyl chain volume dependent phase transition sequence Ia d(L) - I23* - Ia d(S). The re-entry of Ia d phase and loss of supramolecular chirality is attributed to the delicate influence of steric effect at the mono-substitute end and interhelix interaction. Besides, aromatic core fluorination was proved to be a successful tool stabilizing the cubic phases in these dimers.