Future Electronics Research Articles

Riding the Seesaw: what Higgsstrahlung may reveal about massive neutrinos

We investigate if the projected high-precision measurements of the cross section of the Higgsstrahlung process e^+ e^- rightarrow Zh at a future electron–positron collider can be utilised to indirectly probe the fermionic Seesaw models. We consider the two centre-of-mass energies sqrt{s}=240 GeV and 365 GeV, and compare the collider reaches to constraints from electroweak observables, probes of lepton flavour universality and the existing and prospective bounds from searches for lepton flavour violation. For the analysis we assume the limit of an exactly conserved lepton-number symmetry. We find that while any appreciable correction to the Higgsstrahlung cross section is already strictly constrained in the Type-I Seesaw model, effects of up to {mathcal {O}}(10%) are possible within Type-III Seesaw.

Low-thermal-budget synthesis of monolayer molybdenum disulfide for silicon back-end-of-line integration on a 200 mm platform.

Two-dimensional (2D) materials are promising candidates for future electronics due to their excellent electrical and photonic properties. Although promising results on the wafer-scale synthesis (≤150 mm diameter) of monolayer molybdenum disulfide (MoS2) have already been reported, the high-quality synthesis of 2D materials on wafers of 200 mm or larger, which are typically used in commercial silicon foundries, remains difficult. The back-end-of-line (BEOL) integration of directly grown 2D materials on silicon complementary metal-oxide-semiconductor (CMOS) circuits is also unavailable due to the high thermal budget required, which far exceeds the limits of silicon BEOL integration (<400 °C). This high temperature forces the use of challenging transfer processes, which tend to introduce defects and contamination to both the 2D materials and the BEOL circuits. Here we report a low-thermal-budget synthesis method (growth temperature < 300 °C, growth time ≤ 60 min) for monolayer MoS2 films, which enables the 2D material to be synthesized at a temperature below the precursor decomposition temperature and grown directly on silicon CMOS circuits without requiring any transfer process. We designed a metal-organic chemical vapour deposition reactor to separate the low-temperature growth region from the high-temperature chalcogenide-precursor-decomposition region. We obtain monolayer MoS2 with electrical uniformity on 200 mm wafers, as well as a high material quality with an electron mobility of ~35.9 cm2 V-1 s-1. Finally, we demonstrate a silicon-CMOS-compatible BEOL fabrication process flow for MoS2 transistors; the performance of these silicon devices shows negligible degradation (current variation < 0.5%, threshold voltage shift < 20 mV). We believe that this is an important step towards monolithic 3D integration for future electronics.

Quantum anomalous Hall effect with high Chern numbers in functionalized square-octagon Sb monolayers

The quantum anomalous Hall (QAH) effect has attracted continuous attention due to its intriguing properties and potential applications in future electronics. Here, we present our investigation of the electronic and topological properties of a square-octagon Sb monolayer with Mo atoms adsorbed (Mo@so-Sb) using first-principles calculations. Our studies reveal how a trivial insulator can be first engineered into an unusual bipolar magnetic semiconductor (BMS) and then further tuned by strain into a spintronics-favorable half semiconductor (HS) or half metal. Remarkably, with 3.7% compressive strain applied, we achieve a QAH state in Mo@so-Sb with a high Chern number (C = 4) which is much larger than that (C = ±1 or ±2) of the previously predicted Chern insulators. This QAH state is characterized by the appearance of four gapless chiral edge states within the nontrivial band gap, enabling a robust multi-channel low-power-consumption transport. Its nontrivial topology primarily originates from the band inversion between the non-degenerate Mo 4d and Sb 5p orbitals. Additionally, we demonstrate the interesting BMS, HS, and QAH states can be controlled by the Mo adsorption concentrations. Our findings not only provide a versatile means of transforming trivial insulators into the desired spintronics-favorable and topological states, but also open new possibilities for high-performance electronic devices.

Charge transfer enabled by the p-doping of WSe2 for 2D material-based printable electronics

Here, we report the fabrication of high-performance printable WSe2 transistors via the doping of p-type FeCl3 molecules (hole mobility: ∼1.5 cm2 V−1 s−1; on/off ratio: ∼106). A complementary inverter is demonstrated with p-WSe2 and n-MoS2 transistors, which highlights its potential for application in future two-dimensional material-based printable electronics.

Constructing high-capacity and flexible aqueous zinc-ion batteries with air-recharging capability using organic cathodes

Flexible aqueous zinc-ion batteries (AZIBs) with air-recharging capability are a promising self-powered system applied in future wearable electronics. It is desired to develop high-capacity air-rechargeable AZIBs. Herein, we developed a flexible AZIB with air-recharging capability based on trinitrohexaazatrinaphthylene (TNHATN) cathode and a ZnSO4 electrolyte. The flexible Zn//TNHATN battery exhibits high volumetric energy density (21.36 mWh/cm3) and excellent mechanical flexibility. Impressing, the discharged flexible Zn//TNHATN battery can be chemical self-charged via the redox reaction between TNHATN cathode and O2 from the air. After oxidation in air for 15 h, such flexible Zn//TNHATN battery can deliver a high specific capacity of 320 mAh/g at 0.5 A/g, displaying excellent air-recharging capability. Notably, this flexible Zn//TNHATN battery also works well in chemical or/and galvanostatic charging mixed modes, showing reusability. This work provides a new insight for designing flexible aqueous self-powered systems.

Hydrogen bonding-induced high-performance stretchable organic semiconductors: a Review.

Semiconductors are widely used in electron devices. With the development of wearable soft-electron devices, conventional inorganic semiconductors are unable to meet the demand because of their high rigidity and high cost. Thus, scientists construct organic semiconductors with high charge mobility, low cost, eco-friendly, stretchable, etc. Due to the excellent performance of stretchable organic semiconductors, they can be widely used as wearable soft-electron devices, such as stretchable organic field-effect transistors (OFETs), organic solar cells (OSCs), etc. Contains flexible display devices and flexible power sources, which are of great interest for applications of future electron devices. However, there are still some challenges that need to be solved. Commonly, enhancing the stretchability may cause the degradation of charge mobility, because of the destruction of the conjugated system. Currently, scientists find that hydrogen bonding can enhance the stretchability of organic semiconductors with high charge mobility. Thus in this review, based on the structure and design strategies of hydrogen bonding, various hydrogen bonding induced stretchable organic semiconductors are introduced. In addition, the applications of the hydrogen bonding induced stretchable organic semiconductors are reviewed. Finally, the stretchable organic semiconductors design concept and potential evolution trends are discussed. The final goal is to outline a theoretical scaffold for the design of high-performance wearable soft-electron devices, which can also further advance the development of stretchable organic semiconductors for applications.

Low-voltage, solution-processed InZnO thin-film transistors with enhanced performance achieved by bilayer gate dielectrics

Fully solution-processed oxide thin-film transistors (TFTs) have shown a great potential in future printable electronics. However, high defect densities at the dielectric/channel interface have limited the simultaneous achievement of low operating voltage and high device performance. In this Letter, we study the effects of bilayer gate dielectrics in potential performance enhancement of solution-processed indium zinc oxide (IZO) TFTs. Several single and bilayer gate dielectrics are studied in terms of their physical and electrical properties. Compared with IZO TFTs using single-layer ZrOx gate dielectrics, optimized TFTs with ZrOx/AlOx gate dielectrics show an increase in carrier mobility and current on/off ratio by a factor of 3.5 and 27, respectively. The inner mechanisms of the performance enhancement are systematically studied, showing that the significantly improved TFT performance originates from the passivation effects of AlOx, which reduce the trap/defect states at the dielectric/channel interface by approximately an order of magnitude. With a low operating voltage of 2 V, a high mobility of over 10 cm2/V s, a subthreshold swing as low as 89 mV/dec, and a high current on/off ratio of &amp;gt;105, the reported devices might have a great potential in future low-cost, low-power printable electronics.

Transparent-flexible thermoelectric module from In/Ga co-doped ZnO thin films

Transparent-flexible thermoelectric thin films have immense potential as power supplies for future small-sized consumer electronics, the internet of things, and wearable devices. Here, we report the thermoelectric properties of dual Ga and In doped ZnO films (IGZO) deposited on a polyimide substrate with post-thermal treatment in vacuum along with fabricating 4-unileg flexible IGZO thermoelectric devices. All the as-deposited and annealed IGZO films are the preferred (002) orientation and under tensile stress. The post-thermal treatment controls the dopant substitution/diffusion in the host ZnO lattice affecting the film crystallinity, residual stress, and thermoelectric properties. Among the films, the IGZO film annealed at 250 °C has the best power factor of 16.9 μWm−1K−2 with the largest crystal size, lowest tensile stress, highest carrier concentration, and lowest density-of-state effective mass. The practical application of flexible IGZO films was also reported via a 4-unileg-IGZO films thermoelectric module, which achieved an output power about 3.2 nW at ΔT = 120 K.

Multiscale Dot‐Wire‐Sheet Heterostructured Nitrogen‐Doped Carbon Dots‐Ti3C2Tx/Silk Nanofibers for High‐Performance Fiber‐Shaped Supercapacitors

AbstractFiber‐shaped supercapacitors (FSCs) have become one of the significantly strategical flexible energy‐storage materials towards future wearable textile electronics and metaverse technologies. Here, we develop the high‐performance FSCs based on multiscale dot‐wire‐sheet heterostructure microfiber of nitrogen‐doped carbon dots‐Ti3C2Tx/silk nanofibers (NCDs‐Ti3C2Tx/SNFs) hybrids via microfluidic fabrication. Due to the enlarged interlayer spacing, plentiful porous channels, accelerated H+ ion transport dynamics, large electrical conductivity and excellent mechanical strength/flexibility, the NCDs‐Ti3C2Tx/SNFs possesses high volumetric capacitance (2218.7 F cm−3) and reversible charge–discharge stability in 1 M H2SO4 electrolyte. Furthermore, the solid‐state FSCs present high energy density (57.9 mWh cm−3), good capacitance (1157 F cm−3), long‐life cycles (82.3 % capacitance retention after 40000 cycles), which realize the actual energy‐supply applications (powering lamp, watch and toy car).

Multiscale Dot-Wire-Sheet Heterostructured Nitrogen-Doped Carbon Dots-Ti3 C2 Tx /Silk Nanofibers for High-Performance Fiber-Shaped Supercapacitors.

Fiber-shaped supercapacitors (FSCs) have become one of the significantly strategical flexible energy-storage materials towards future wearable textile electronics and metaverse technologies. Here, we develop the high-performance FSCs based on multiscale dot-wire-sheet heterostructure microfiber of nitrogen-doped carbon dots-Ti3 C2 Tx /silk nanofibers (NCDs-Ti3 C2 Tx /SNFs) hybrids via microfluidic fabrication. Due to the enlarged interlayer spacing, plentiful porous channels, accelerated H+ ion transport dynamics, large electrical conductivity and excellent mechanical strength/flexibility, the NCDs-Ti3 C2 Tx /SNFs possesses high volumetric capacitance (2218.7 F cm-3 ) and reversible charge-discharge stability in 1 M H2 SO4 electrolyte. Furthermore, the solid-state FSCs present high energy density (57.9 mWh cm-3 ), good capacitance (1157 F cm-3 ), long-life cycles (82.3 % capacitance retention after 40000 cycles), which realize the actual energy-supply applications (powering lamp, watch and toy car).

Effect of Annealing on Graphene/PVDF Nanocomposites.

In this study, the process for tuning the electrical properties of graphene/polyvinylidene fluoride (Gr/PVDF) nanocomposite films by a thermal annealing process is explored. The surface morphology and microstructure of the nanocomposite were characterized. The effect of temperature on the electrical conductivity was investigated by heating and cooling the sample from the room temperature up to 150 °C. The effect of annealing on the electrical conductivity was recorded as a function of annealing temperature. A Hall effect measurement was conducted as a function of annealing temperatures to obtain Hall voltage (V H), carrier mobility (μH), carrier concentration (n H), Hall coefficient (R H), resistivity, and carrier conductivity type (n or p). It was found that the films annealed at 150 °C exhibited the best electrical conductivity of Gr/PVDF films. This study may provide an insight into the development and utilization of Gr/PVDF films in future electronics and the potential applications in various sectors such as aerospace, automotive, and biomedical industries.

A first-principles study of hydrostatic strain engineering on the electronic properties of β-Ga2O3

β-Ga2O3 has some prominent advantages over other wide band gap semiconductors for application in electronics and optoelectronics. Through density functional theory, the effects of hydrostatic strain on the electronic properties of β-Ga2O3 are investigated. It is found that the band gap of β-Ga2O3 increases and subsequently decreases almost linearly with the hydrostatic strain from −8% to 7%, thus, resulting in the band gap within 3.45–6.28eV. As the strain exceeds −8% or 7%, the phase transition emerges, and its electronic properties exhibit abnormal variation trends as compared to primitive β-Ga2O3. In addition, properties, such as electron effective mass, elastic constants, relaxation time and mobility, show remarkable anisotropy. For the β-Ga2O3 phase with strains, electron mobility along a, b and c directions can be modulated about 2–3 times. The significant range of electronic parameters indicates that strain engineering may be an important approach to meet the different requirements of future electronics.

Distinct Contact Scaling Effects in MoS2 Transistors Revealed with Asymmetrical Contact Measurements.

2D semiconducting materials have immense potential for future electronics due to their atomically thin nature, whichenables better scalability. While the channel scalability of 2D materials has been extensively studied, the current understanding of contact scaling in 2D devices is inconsistent andoversimplified. Here physically scaled contacts and asymmetrical contact measurements (ACMs) are combined to investigate the contact scaling behavior in 2D field-effect transistors. The ACMs directly compare electron injection at different contact lengths while using the exact same MoS2 channel, eliminating channel-to-channel variations.Theresults show that scaled source contacts can limit the drain current, whereas scaled drain contacts do not. Compared to devices with long contact lengths, devices with short contact lengths (scaled contacts) exhibit larger variations, 15% lower drain currents at high drain-source voltages, and a higher chance ofearly saturation and negative differential resistance. Quantum transport simulations reveal that the transfer length of Ni-MoS2 contacts can be as short as 5nm. Furthermore,it isclearly identified that the actual transfer length depends on the quality of the metal-2D interface. The ACMs demonstrated here will enable further understanding of contact scaling behavior at various interfaces.

A 2.6 V Flexible Supercapacitor Based on Al-MnO2-Na2SO4//AC-KOH with High Specific Energy

In this work, we have synthesized Al-doped MnO2 nanoparticles (Al-MnO2) by rapid coprecipitation followed by hydrothermal and heat treatment. Al-MnO2 shows a specific capacitance of 301.8 F g–1 at 1 A g–1 in a sample of 14% Al-MnO2-260 °C. The specific capacitance still remains at 206 F g–1 at 20 A g–1. It also shows a good cycling stability with no capacitance degradation after 5000 cycles. More importantly, a new type of supercapacitor, Al-MnO2|PVA-Na2SO4//PVA-KOH|AC, has been designed using a Na2SO4-poly(vinyl alcohol)//cation exchange membrane//KOH-poly(vinyl alcohol)-based decoupled electrolyte. This device exhibits a specific capacitance of 68.9 F g–1 at 1 A g–1, corresponding to 64.7 Wh kg–1 at 1300 W kg–1. It also delivers a good capacitance retention of ∼84% after 5000 cycles. The cell voltage is up to 2.6 V, which could light up a green light-emitting diode. The PVA-based decoupled gel electrolyte offers good processability to assemble flexible and foldable devices, which is important for mass production in manufacturing. These results clearly indicate that such high-voltage flexible supercapacitors with high specific energy are very promising in future wearable electronics.

Joint‐Inspired Liquid and Thermal Conductive Interface for Designing Thermal Interface Materials with High Solid Filling yet Excellent Thixotropy (Adv. Funct. Mater. 14/2023)

Contact Thermal Resistance In article number 2214071, Kai Wu, Qiang Fu, and co-workers report a joint-inspired interfacial engineering strategy by employing liquid metal to the surface of rigid alumina, which improves material's thermal conductivity and thixotropy. This method will inspire development of high-performance polymer-based thermal interface materials for future advanced electronics.

Van der Waals-Interface-Dominated All-2D Electronics.

The interface is the device. As the feature size rapidly shrinks, silicon-based electronic devices are facing multiple challenges of material performance decrease and interface quality degradation. Ultrathin 2D materials are considered as potential candidates in future electronics by their atomically flat surfaces and excellent immunity to short-channel effects. Moreover, due to naturally terminated surfaces and weak van der Waals (vdW) interactions between layers, 2D materials can be freely stacked without the lattice matching limit to form high-quality heterostructure interfaces with arbitrary components and twist angles. Controlled interlayer band alignment and optimized interfacial carrier behavior allow all-2D electronics based on 2D vdW interfaces to exhibit more comprehensive functionality and better performance. Especially, achieving the same computing capacity of multiple conventional devices with small footprint all-2D devices is considered to be the key development direction of future electronics. Herein, the unique properties of all-2D vdW interfaces and their construction methods are systematically reviewed and the main performance contributions of different vdW interfaces in 2D electronics are summarized, respectively. Finally, the recent progress and challenges for all-2D vdW electronics are discussed, and how to improve the compatibility of 2D material devices with silicon-based industrial technology is pointed out as a critical challenge.

Deep learning searches for vector-like leptons at the LHC and electron/muon colliders

The discovery potential of both singlet and doublet vector-like leptons (VLLs) at the Large Hadron Collider (LHC) as well as at the not-so-far future muon and electron machines is explored. The focus is on a single production channel for LHC direct searches while double production signatures are proposed for the leptonic colliders. A Deep Learning algorithm to determine the discovery (or exclusion) statistical significance at the LHC is employed. While doublet VLLs can be probed up to masses of 1 TeV, their singlet counterparts have very low cross sections and can hardly be tested beyond a few hundreds of GeV at the LHC. This motivates a physics-case analysis in the context of leptonic colliders where one obtains larger cross sections in VLL double production channels, allowing to probe higher mass regimes otherwise inaccessible even to the LHC high-luminosity upgrade.

Carbon dots integrated into nickel-cobalt hydroxide as superior electrode for supercapattery

Nickel hydroxide (Ni(OH)2) is one of the most valuable electrode materials for supercapacitors. Owing to the low stability and conductivity of Ni(OH)2 electrode, the preparation of a fast and high-stability Ni(OH)2 electrode is a significant challenge. Nickel hydroxide integrated with cobalt and carbon dots (CDs-Co/Ni(OH)2) as a high performance electrode has been prepared by cathodic electrodeposition for supercapattery in this work. Compared with unintegrated Ni(OH)2 electrode or carbon dots integrated Ni(OH)2 electrode, the introduction of Co greatly improves the stability of the Ni(OH)2 electrode, particularly at high current density. The as-obtained CDs-Co/Ni(OH)2 electrode presents a high specific capacitance of 338.6 mAh/g at 5 A/g and an extraordinary cycling stability with 1000 cycles even under a high current density of 40 A/g (retaining 84.6%). Besides, the CDs-Co/Ni(OH)2 electrode exhibits an energy density of 281.2 Wh/kg at a power density of 57.2 kW/kg. Such a glorious stable CDs-Co/Ni(OH)2 electrode may provide significant insight into future multifarious electronics and electrified vehicle applications.

Moisture-Enabled Germination of Heat-Activated Bacillus Endospores for Rapid and Practical Bioelectricity Generation: Toward Portable, Storable Bacteria-Powered Biobatteries.

Small-scale battery-like microbial fuel cells (MFCs) are a promising alternative power source for future low-power electronics. Controllable microbial electrocatalytic activity in a miniaturized MFC with unlimited biodegradable energy resources would enable simple power generation in various environmental settings. However, the short shelf-life of living biocatalysts, few ways to activate the stored biocatalysts, and extremely low electrocatalytic capabilities render the miniature MFCs unsuitable for practical use. Here, heat-activated Bacillus subtilis spores are revolutionarily used as a dormant biocatalyst that can survive storage and rapidly germinate when exposed to special nutrients that are preloaded in the device. A microporous, graphene hydrogel allows the adsorption of moisture from the air, moves the nutrients to the spores, and triggers their germination for power generation. In particular, forming a CuO-hydrogel anode and an Ag2 O-hydrogel cathode promotes superior electrocatalytic activities leading to an exceptionally high electrical performance in the MFC. The battery-type MFC device is readily activated by moisture harvesting, producing a maximum power density of 0.4mW cm-2 and a maximum current density of 2.2mA cm-2 . The MFC configuration is readily stackable in series and a three-MFC pack produces enough power for several low-power applications, demonstrating its practical feasibility as a sole power source.

Dysprosium Incorporation for Phase Stabilization of Atomic-Layer-Deposited HfO2 Thin Films

The relatively low thermal stability of HfO2 films severely affects the performance of semiconductor devices. For instance, the low crystallization temperature of HfO2 (∼500 °C) leads to the formation of grain boundaries, which increases the leakage current. In this study, Dy incorporation leads to the phase transformation of HfO2 films from various directional planes to a main m(−111) plane by the crystallographic stabilization of HfO2 films, increasing the size of grains. Dy-doped HfO2 thin films with modulated doping content, prepared by plasma-enhanced atomic layer deposition (PE-ALD), are characterized by analysis of their chemical composition combined with electron microscopy and synchrotron X-ray techniques. The transformation from m(110), m(−111), m(111), m(020), and m(120) to a main m(−111) plane is observed through X-ray diffraction, which indicates that Dy plays a role for the phase stabilization of HfO2 films. The atomic-scale images of the cross section and top view obtained using an electron microscope demonstrate that the in-plane average grain size is increased by approximately 4 times due to Dy incorporation compared with that of single HfO2 films. The reduction in the area of the grain boundary of HfO2 due to Dy incorporation decreases the leakage current density of HfO2 by 1000 times and increased the breakdown strength. This result can aid future electronics by determining the effect of a dopant on the crystallographic structure of host thin-film materials.