Future Electronics Research Articles

Threshold photoproduction of ηc and ηb using holographic QCD

We discuss the possibility that threshold photoproduction of ηc,b may be sensitive to the pseudovector 1+− glueball exchange. We use the holographic construction to identify the pseudovector glueball with the Kalb-Ramond field, minimally coupled to bulk Dirac fermions. We derive the holographic C-odd form factor and its respective charge radius. Using the pertinent Witten diagrams, we derive and analyze the differential photoproduction cross section for ηc,b in the threshold regime, including the interference from the dual bulk photon exchange with manifest vector dominance. The possibility of measuring this process at current and future electron facilities is discussed. Published by the American Physical Society 2024

Triboelectrically active hydrogel drives self-charging zinc-ion battery and human motion sensing

The fast advancement of flexible electronic technology hastens an ever-growing demand for power sources that are adaptable and flexible, and the arrival of innovative energy harvesting technologies such as triboelectric nanogenerator (TENG) further endow the potable electronics with versatility and sustainability. Herein, polyvinyl alcohol/ polyacrylamide/ zinc sulfate (PPZ) hydrogel was synthesized via an one-step UV-initiated polymerization. The hydrogel demonstrates exceptional tensile properties (with a large strain of 915 % and a corresponding tensile strength of 231 KPa), excellent electrical conductivity and light transmittance. A highly flexible and easily adaptable single-electrode TENG was thus fabricated on the base of the as-synthetized PPZ (PPZ-TENG), where the PPZ hydrogel functions as both the charging layer and current collector. While promoting a high electrical output performance of the PPZ-TENG (an open circuit voltage of 176 V and a power density of 328 mW/m2), the PPZ hydrogel also serves as an efficient ion-conductive electrolyte to construct highly flexible self-charging zinc ion batteries (ZIBs). Besides, highly sensitive strain response toward environmental stimuli was also demonstrated, which makes the integration strategy a promising solution for future development self-powered flexible wearable electronics toward the sustainable monitoring of human vital signs such as pulse and limb movement.

MnO/ZnO:Zn Thin-Film Frequency Adaptive Heterostructure for Future Sustainable Memristive Systems.

In recent years, advances in materials engineering based on adaptive electronics have found a new paradigm to optimize drawbacks in signal processing. A two-layer MnO/ZnO:Zn heterostructure envisioned for frequency adaptive electronic signal processing is synthesized by sputtering, where the use of internal states allows reconfigurability to obtain new operating modes at different frequency input signals. X-ray diffraction (XRD) analysis is performed on each layer, revealing a cubic structure for MnO and a hexagonal structure for ZnO:Zn with preferential growth in [111] and [002] directions, respectively. Scanning electron microscope (SEM) micrographs show that the surface of both materials is homogeneous and smooth. The thickness for each layer is determined to be approximately 106.3 nm for MnO, 119.3 nm for ZnO:Zn and 224.1 nm for the MnO/ZnO:Zn structure. An electrical characterisation with an oscilloscope and signal generator was carried out to obtain the time-response signals and current-voltage (I-V) curves, where no degradation is detected when changing frequencies within the range of 100 Hz to 1 MHz. An equivalent circuit is proposed to explain the effects in the interface. Measurements of switching speeds from high resistance state (HRS) to low resistance state (LRS) at approximately 17 ns, highlight the device's rapid adaptability, and an estimated switching ratio of approximately 2 × 104 indicates its efficiency as a memristive component. Finally, the MnO/ZnO:Zn heterojunction delivers states that are stable, repeatable, and reproducible, demonstrating how the interaction of the materials can be utilised in adaptive device applications by applying frequencies and internal states to create new and innovative design schematics, thus reducing the number of components/connections in a system for future sustainable electronics.

2D Conjugated Polymer Thin Films for Organic Electronics: Opportunities and Challenges.

2D conjugated polymers (2DCPs) possess extended in-plane π-conjugated lattice and out-of-plane π-π stacking, which results in enhanced electronic performance and potentially unique band structures. These properties, along with predesignability, well-defined channels, easy postmodification, and order structure attract extensive attention from material science to organic electronics. In this review, the recent advance in the interfacial synthesis and conductivity tuning strategies of 2DCP thin films, as well as their application in organic electronics is summarized. Furthermore, it is shown that, by combining topology structure design and targeted conductivity adjustment, researchers have fabricated 2DCP thin films with predesigned active groups, highly ordered structures, and enhanced conductivity. These films exhibit great potential for various thin-film organic electronics, such as organic transistors, memristors, electrochromism, chemiresistors, and photodetectors. Finally, the future research directions and perspectives of 2DCPs are discussed in terms of the interfacial synthetic design and structure engineering for the fabrication of fully conjugated 2DCP thin films, as well as the functional manipulation of conductivity to advance their applications in future organic electronics.

A Compact Model for Carbon Nanotube Field Effect Transistors Incorporating Temperature Effects and Application for Operational Amplifier Design

Semiconducting carbon nanotubes (CNTs), characterized by high carrier mobility and atomic thickness, are considered ideal channel materials for building high-performance and ultimate-scale field-effect transistors for future electronics. Here, we present a data-calibrated compact model of CNT field-effect transistors (CNTFETs) that incorporates temperature effects using the virtual source approach. The proposed model also includes the self-heating effect. Temperature effect was characterized by the influence of temperature on devices, achieved through establishing a temperature-dependent semi-empirical model of carrier mobility and carrier velocity. The proposed model can be easily implemented in a simulator. We designed a two-stage operational amplifier (OPAMP) using the proposed model at 32 nm technology. Compared with other studies, the designed CNTFET-based OPAMP demonstrates lower power consumption, which is beneficial for exploring the biological applications of low-power analog circuits in portable electronic devices. Furthermore, the impact of thermal variations on the design of OPAMP, as per the proposed model, was delineated. Investigations revealed that our circuit maintains a high common mode rejection ratio, which diminishes as the temperature increases and exhibits a moderate gain value that escalates with temperature.

Multifunctional AZO/Ag(O)‐Based Transparent Conductor for Flexible and Transparent Optoelectronics

Transparent photovoltaics (TPVs) generate electric power by selectively harvesting ultraviolet and/or near‐infrared light. If integrated with electronic products, TPV can sustainably power the products without affecting the user experience. Future electronics require flexibility and lightweight, hence the integrated TPV should also be flexible. To achieve this, a flexible, transparent conducting platform is desirable. A binary transparent conductor (TC) based on Ag(O) has been studied for flexible TPV. The oxygen‐induced Ag growth provides better Ag wettability, enabling a low sheet resistance of 12.5 Ω sq−1 at an Ag thickness of 6.5 nm. The AZO/Ag(O) binary structure, with an average visible transmittance value of 86%, has a figure of merit of 17.7 (10−3 Ω−1), which surpasses conventional TCs such as fluorine‐doped tin oxide and indium‐doped tin oxide . Furthermore, the multilayer design of Ag(O)‐based TC allows interfacial engineering to enhance the performance of TPV. The optimum photovoltaic performance of NiO/ZnO TPV is achieved with an AZO thickness of 12 nm, providing a performance enhancement of 700%. The NiO/ZnO/AZO/Ag(O) device exhibits a stable photovoltaic effect with a consistent open‐circuit voltage value of 0.4 V after numerous bending cycles with a bending radius of 0.7 cm.

Submicron-Thickness Ultraflexible Organic Light-Emitting Diodes via a Photoregulated Stripping Strategy.

With the rapid advances in imperceptible and epidermal electronics, the research on ultraflexible organic light-emitting diodes (OLEDs) has become increasingly significant, owing to their excellent flexibility and conformability to the human body. It is highly desirable to develop submicrometer-thick ultraflexible OLEDs to enable the devices to seamlessly conform to the surface of arbitrary-shaped objects and still function properly. However, it remains a huge challenge for currently reported OLEDs due to the lack of an appropriate stripping strategy. Here, for the first time, we develop a facile photoregulated stripping strategy for the fabrication of high-performance ultraflexible OLEDs with submicron thickness. Under ultraviolet (UV) irradiation, the surface adhesion force of the ultrathin photopolymer membrane can be adjusted from 16.9 to 5.1 N/m, thereby effectively controlling the laminating and detaching process. Based on this strategy, the resultant device thickness is as low as 0.821 μm, which is the lowest record among flexible OLEDs reported to date. More remarkably, excellent electrical properties with a maximum current efficiency (CE) of 62.5 cd/A, an external quantum efficiency (EQE) of 17.8%, and a low turn-on voltage of 2.5 V are realized, which are superior to almost all of the reported ultraflexible OLEDs with thicknesses below 10 μm. Based on versatile ultraflexible OLEDs, all-organic and skin-mounted displays are successfully realized by employing a conformable organic thin-film transistor (OTFT) as the driver. This work offers a feasible strategy for advancing OLEDs from flexible to ultraflexible, showing significant application potential in future epidermal electronics and conformal displays.

Performance analysis of OTFT with varying semiconductor film thickness for future flexible electronics

The goal of this study was to get a deeper understanding of the intricate impact of organic semiconductor thickness on the performance of devices, using a thorough and meticulous investigation at the microscopic level incorporating the density of defect model using using Silvaco ATLAS TCAD Simulator. The present work thoroughly investigates the relationship between the thickness of semiconductors and important performance parameters, such as hole concentration, electric potential, electric field, and Hole QFL. The comprehensive insights derived from this research not only enhance the comprehension of device physics but also provide a framework for the systematic enhancement of electronic devices. The widespread use of organic thin film transistors (OTFT) in future Flexible electronics, particularly in display and memory circuits, necessitates the incorporation of low voltage, high speed, and low cost characteristics.

Study on schottky barrier of Cu/Graphene/4H-SiC interface based on first principles

High stability 4H-SiC ohmic contact is currently a key technical challenge that silicon carbide devices urgently need to overcome. In the paper, the interfacial structures, atomic interactions and Schottky barrier height (SBH) of Cu/Graphene/4H-SiC were studied using the first-principles method. According to research, the SBH for Cu/G/4H-SiC is lower than the SBH for Cu/4H-SiC. The reasons for this phenomenon mainly include the following: 1. The graphene C atoms saturate the dangling bonds on the 4H-SiC surface and the influence of the metal-induced-gap-states (MIGS) at the interface is decreased. 2. A new phase is formed by inserting graphene between the Cu and 4H-SiC have low work functions. 3. An interfacial-electric-dipole layer (IEDL) formed at the interface of 4H-SiC and graphene may also reduce the SBH. These results make them to be promising candidates for future radiation resistant electronics.

First Principle Study on Schottky Barrier at Ni/Graphene/4H-SiC Interface

High stability 4H-SiC ohmic contact is currently a key technical challenge that silicon carbide devices urgently need to overcome. It is important to reduce the Schottky barrier height (SBH) at the Ni/4H-SiC interface to optimize ohmic contact. In this paper, the mechanisms of graphene layer changing Ni/4H-SiC interface Schottky barrier height (SBH) are studied based on the first-principles method within the local density approximation. Theoretical studies have shown that graphene intercalation can reduce the SBH of Ni and 4H-SiC interfaces. The reason of SBH reduction may be that the graphene C atoms saturate the dangling bonds on the 4H-SiC surface and the influence of the metal-induced energy gap state at the interface is reduced. In addition, the new phase formed at the interface of graphene and silicon carbide has a lower work function. Furthermore, an interfacial electric dipole layer may be formed at the 4H-SiC/graphene interface which may also reduce the SBH. These results make them to be promising candidates for future radiation resistant electronics.

Improving Cathode Testing with a High-Gradient Cryogenic Normal Conducting RF Photogun

Future electron accelerator applications such as X-ray free electron lasers and colliders are dependent on significantly increasing beam brightness. With the observation that linac beam manipulation’s best preservation of max brightness is at the cathode, we are incentivized to create an environment where we can study how to achieve the highest possible photogun brightness. In order to do so, we intend to extract beams from high-brightness photocathodes with the highest achievable accelerating gradients we can manage in a klystron-powered radiofrequency (RF) photogun. We utilize here cryogenic normal conducting cavities to achieve ultra-high gradients via limitation of breakdown rates (BDR). The low temperatures should also reduce cathode emittance by reducing the mean transverse energy (MTE) of electrons near the photoemission threshold. To this end, we have designed and produced a new CrYogenic Brightness-Optimized Radiofrequency Gun (CYBORG) for use in a new beamline at UCLA. We will introduce the enabling RF and photoemission physics as a primer for the new regime of high field low temperature cathodes we intend to enter. We further report the current status of the beamline commissioning, including the cooling of the photogun to 100 K, and producing 0.5 MW of RF feed power, which corresponds to cathode accelerating fields in the range of 80–90 MV/m. We further plan iterative improvements to both to 77 K and 1 MW corresponding to our ultimate goal >120 MV/m. Our discussion will include future beamline tests and the consideration of the initial realization of an ultra-high-gradient photoinjector concept.

The role of isotope mass on neutral fueling and density pedestal structure in the DIII-D tokamak

Experimental measurements on DIII-D of hydrogen neutral penetration lengths ( λn0 ) on the high field side (HFS) are longer by a factor of 2 than for deuterium consistent with the thermal velocity ratio for neutrals at the same temperature (vthH/vthD=2) . This ratio is constant for both low and high pedestal electron density. At low pedestal density (ne∼4×1019 m −3) , the neutral penetration length is greater than the density pedestal width for both isotopes, and the additional 40% increase of neutral penetration in hydrogen widens the pedestal by the same amount. As the density pedestal height increases (ne∼6×1019 m −3) , the neutral penetration lengths drop below the density pedestal widths for both isotopes, and the increased penetration of hydrogen has no increased effect on the pedestal width compared to deuterium. Extrapolating to future reactor-relevant high electron density pedestals, the isotope-mass change in neutral fueling on the HFS from the deepest neutral penetration of hydrogen, to the shortest neutral penetration of tritium will be negligible (0.2–0.4 cm) in comparison to estimates of the density pedestal width (6–8.5 cm).

Probing valence quark width of the proton in deeply virtual Compton scattering at high energies* *Supported by the National Natural Science Foundation of China (12165004), the Basic and Applied Basic Research Project of Guangzhou Science and Technology Bureau (202201011324), the Education Department of Guizhou Province, China (QJJ[2022]016) and the National Key Research and Development Program of China (2018YFE0104700, CCNU18ZDPY04)

We use the refined hot spot model to study the valence quark shape of the proton with the deeply virtual Compton scattering at high energies in the color glass condensate framework. To investigate the individual valence quark shape, a novel treatment of the valence quark width is employed. We calculate the cross-sections for coherent and incoherent deeply virtual Compton scattering using, for the first time, different widths ( and ) for the profile density distributions of the up and down quarks instead of using the same width as in the literature. We find that the cross-sections calculated with at each collision energy are consistent with each other, which is in agreement with theoretical expectations, whereas those computed with show some discrepancies. This outcome implies that the up quark might emit more gluons than the down quark, leading to at high energy. The impact of energy on the outcome is estimated. Our results show that as the collision energy increases, the aforementioned discrepancies are not only significantly broadened, but also shift to a relatively smaller momentum transfer range at the future Electron-Ion Collider (EIC) and Large Hadron Electron Collider (LHeC) energies, which indicates that the EIC and LHeC can provide an unprecedented chance to access the shape of the valence quark of the proton.

Topological electronic states in holey graphyne

We unveil that the holey graphyne (HGY), a two-dimensional carbon allotrope where benzene rings are connected by two −C≡C− bonds fabricated recently in a bottom-up way, exhibits topological electronic states. Using first-principles calculations and Wannier tight-binding modeling, we discover a higher-order topological invariant associated with C 2 symmetry of the material, and show that the resultant corner modes appear in nanoflakes matching to the structure of precursor reported previously, which are ready for direct experimental observations. In addition, we find that a band inversion between emergent g-like and h-like orbitals gives rise to a nontrivial topology characterized by Z2 invariant protected by an energy gap as large as 0.52 eV, manifesting helical edge states mimicking those in the prominent quantum spin Hall effect, which can be accessed experimentally after hydrogenation in HGY. We hope these findings trigger interests towards exploring the topological electronic states in HGY and related future electronics applications.

Artificial Optoelectronic Synapses Based on Light‐Controllable Ferroelectric Semiconductor Memristor

AbstractNumerous synaptic devices have been explored for the next generation of energy‐efficient computing techniques. Among them, optoelectronic synaptic devices based on semiconductor/ferroelectric heterostructures have received a lot of attention lately due to their amazing parallelism, efficiency, and fault tolerance properties. However, polarizing the ferroelectric layer or gating the dielectric layer is necessary to achieve tunable synaptic functions, which generally causes an increase in energy consumption and complex manufacturing processes. Here, a simple and efficient method is demonstrated to develop a tunable optoelectronic synaptic device based on a single ferroelectric semiconductor, BiFeO3‐BaTiO3 (BF‐BT). Multi‐essential synaptic functions including short‐term plasticity, paired‐pulse facilitation, and long‐term plasticity are all satisfactorily replicated by the memristor device. More significantly, light‐controllable synaptic behaviors are realized by altering the ferroelectric polarization state of BF‐BT. Synaptic devices’ relaxation characteristics enable simulation of the effects of positive/negative emotions on learning and forgetting processes. This study highlights the potential of the ferroelectric semiconductor memristor in constructing the efficient optoelectronic synapses for future neuromorphic electronics with the ability to learn and sense optical information.

CMS HGCAL electronics vertical integration system tests

In preparation for the High-Luminosity phase of the CERN Large Hadron Collider, the Compact Muon Solenoid collaboration will replace the existing endcap calorimeters with the High Granularity Calorimeter. Considering both endcaps, this novel sub-detector will have around six million readout channels, pushing approximately 108 Tbit s-1 of usable data between the detector front-end (on-detector) electronics and the back-end (off-detector) electronics. Given the scale and complexity of the endcap calorimeter upgrade project, the electronics testing must be carefully planned. The strategy has been to split the efforts between vertical (start-to-end) and horizontal (parallelisation) test systems wherever possible. An important milestone was the development and operation of a test system that prototypes a complete vertical slice of the future endcap electronics system. For the first time, a version of a test system consisting of the full vertical electronics readout chain was successfully operated in a beam test, where it was used to acquire real physics data.

Enhancement-Mode Ambipolar Thin-Film Transistors and CMOS Logic Circuits using Bilayer Ga2O3/NiO Semiconductors.

Recent advancements in power electronics have been driven by Ga2O3-based ultrawide bandgap (UWBG) semiconductor devices, enabling efficient high-current switching. However, integrating Ga2O3 power devices with essential silicon CMOS logic circuits for advanced control poses fabrication challenges. Researchers have introduced Ga2O3-based NMOS and pseudo-CMOS circuits for integration, but these circuits may either consume more power or increase the design complexity. Hence, this article proposes Ga2O3-based CMOS realized using heterogeneous 3D-stacked bilayer ambipolar transistors. These ambipolar transistors consist of HfO2/NiO/Ga2O3/NiO/HfO2 heterostructures that are wrapped around by the Ti/Au gate electrode, resulting in record high electron and hole current on/off ratios of 109 and 107. The threshold voltage, subthreshold swing, and current density measured from 100 ambipolar devices (across 5 batches) are around -7.99 ± 0.92 V (p-channel) and 7.81 ± 0.81 V (n-channel), 0.59 ± 0.07 V/dec (p-channel) and 0.61 ± 0.06 V/dec (n-channel), and 0.99 ± 0.26 mA/mm (p-channel) and 58.23 ± 12.99 mA/mm (n-channel), respectively. All the 100 ambipolar devices showed decent long-term stability over a period of 200 days, exhibiting reliable electrical performance. The threshold voltage shift (ΔVTH) after negative bias stressing for a period of 3500 s is around 11.52 V (p-channel) and 10.21 V (n-channel), respectively. Notably, the n-channels exhibit ∼2 orders higher on/off ratio than the best Ga2O3 unipolar transistors at 300 °C. Moreover, the polarities of ambipolar transistors are reconfigurable into p- or n-MOS, which are integrated to demonstrate CMOS inverter, NOR, and NAND logic gates. The switching periods from "0" to "1" and from "1" to "0" of NOR are 0.12 and 0.17 μs, and those of NAND are 0.16 and 0.13 μs. This work lays the foundation of oxide-semiconductor-based CMOS for future integrated electronics.

Programmable Ferroelectricity in Hf0.5Zr0.5O2 Enabled by Oxygen Defect Engineering.

Ferroelectricity, especially the Si-compatible type recently observed in hafnia-based materials, is technologically useful for modern memory and logic applications, but it is challenging to differentiate intrinsic ferroelectric polarization from the polar phase and oxygen vacancy. Here, we report electrically controllable ferroelectricity in a Hf0.5Zr0.5O2-based heterostructure with Sr-doped LaMnO3, a mixed ionic-electronic conductor, as an electrode. Electrically reversible extraction and insertion of an oxygen vacancy into Hf0.5Zr0.5O2 are macroscopically characterized and atomically imaged in situ. Utilizing this reversible process, we achieved multilevel polarization states modulated by the electric field. Our study demonstrates the usefulness of the mixed conductor to repair, create, manipulate, and utilize advanced ferroelectric functionality. Furthermore, the programmed ferroelectric heterostructures with Si-compatible doped hafnia are desirable for the development of future ferroelectric electronics.

Interface engineering driven molybdenum disulfide coupled polyaniline functionalized carbon fabric with high mass loading anode for fiber lithium-ion batteries

Carbon fiber (CF) cloth presents a preeminent substrate for growing numerous active materials, emerging as a promising electrode design in fiber lithium-ion batteries (F-LiBs) for powering future wearable electronics. Nevertheless, the hydrophobic nature of CF affects the interaction between the active materials and CF, leading to inferior battery performance. Herein, we report a polyaniline (PANi) driven interface-engineering approach to address the recurring issue associated with CF. To demonstrate the concept, molybdenum disulfide (MoS2), a two-dimensional layered anode was grown on PANi-functionalized CF (MoS2/PANi/CF). The nitrogen functionalities of the PANi backbone enriched the surface functionality and facilitated the coupling adhesion between MoS2 and CF. This key feature influenced the charge transport kinetics across the MoS2/CF interface and preserved the structural integrity. More importantly, the strong coordination interaction between MoS2 and PANi improved the growth density of MoS2, resulting in high mass loading. Given these merits, the interfacially coupled MoS2/PANi/CF anode delivered a high specific capacity and enhanced rate and cycling performances. This study verifies the significance of the interface engineering approach, which can be extended to developing wide arrays of flexible electrodes for other wearable battery chemistries.

Recent Progress in Electric‐field Enhanced 3D Graphene Electrodes using Laser Scribing for In‐plane Microsupercapacitors

AbstractThe increasing demand for miniature, flexible electronic devices have fueled the need for compact and high‐performing energy storage solutions. Microsupercapacitors (mSCs) with reduced dimension and novel electrode design have gained prominence. This concept paper summarizes and views the recent advancements in mSCs with a focus on 3D graphene electrodes and their novel electrode design to increase energy performance of the devices. Especially, we focus on these 3D graphene structures fabricated using a laser‐scribing method which offer an efficient, cost‐effective approach for enhanced mSC performance. Further, this work delves into the vital link between the electrical field effect and geometrically engineered interdigitated electrodes, which is pivotal for maximizing the ion transport and mSC energy storage performance. The insights presented here are promising for meeting the power requirements of future miniature electronics.