High-quality Interface Research Articles

The Quality Learning System Interface Factor of Success Blended Learning

In order to effectively deliver the learning process to both educators and learners, a high-quality LMS interface design is essential. This research's primary goal is to present a thorough understanding of the quality interface elements that influence a blended learning environment's performance. A quantitative research approach, using a questionnaire, was used. A total of 70 participants were surveyed using the questionnaire. This study shows that the fundamental predictors of quality interface were the most significant positive factor and more critical to the success of blended learning.

Boltzmann Switching MoS2 Metal-Semiconductor Field-Effect Transistors Enabled by Monolithic-Oxide-Gapped Metal Gates at the Schottky-Mott Limit.

A gate stack that facilitates a high-quality interface and tight electrostatic control is crucial for realizing high-performance and low-power field-effect transistors (FETs). However, when constructing conventional metal-oxide-semiconductor structures with two-dimensional (2D) transition metal dichalcogenide channels, achieving these requirements becomes challenging due to inherent difficulties in obtaining high-quality gate dielectrics through native oxidation or film deposition. Here, a gate-dielectric-less device architecture of van der Waals Schottky gated metal-semiconductor FETs (vdW-SG MESFETs) using a molybdenum disulfide (MoS2) channel and surface-oxidized metal gates such as nickel and copper is reported. Benefiting from the strong SG coupling, these MESFETs operate at remarkably low gate voltages, <0.5V. Notably, they also exhibit Boltzmann-limited switching behavior featured by a subthreshold swing of ≈60mVdec-1 and negligible hysteresis. These ideal FET characteristics are attributed to the formation of a Fermi-level (EF) pinning-free gate stack at the Schottky-Mott limit. Furthermore, authors experimentally and theoretically confirm that EF depinning can be achieved by suppressing both metal-induced and disorder-induced gap states at the interface between the monolithic-oxide-gapped metal gate and the MoS2 channel. This work paves a new route for designing high-performance and energy-efficient 2D electronics.

Evolution of microstructure and texture and their influence on the strength of an accumulative roll bonded (ARBed) Al-Sc-Zr-Er-Ti alloy

Accumulative roll bonding (ARB) is an effective approach to improve the strength of metal sheets. This work studied the evolution of microstructure and texture and their influence on the strength of an ARBed Al-Sc-Zr-Er-Ti alloy, produced by multi-microalloying Sc, Zr, Er, and Ti into pure Al. A high-quality interface and a fine microstructure with an average grain size of ∼0.6 μm were achieved as by the ARB process. The Dillamore {4411} <11118> and the Copper {112} <111> components were sharpened in final texture as is common in ARB. However, after the 5th cycle, there was a new texture component along the α-fiber, at (φ1, Φ, φ2) ≡ (60°, 45°, 0°) in Euler space. The yield strength (YS) and tensile strength (UTS) increased with increasing the number of ARB cycles. The 7th ARBed Al-Sc-Zr-Er-Ti alloy had increased YS by 45% and UTS by 57%, respectively, compared to the initial cold rolled sheet. Strengthening was mainly attributed to dislocation strengthening, grain refinement strengthening and precipitation strengthening. There was little texture strengthening because of a strengthening and softening alternation with the change of ARB cycle.

High-κ Dielectric (HfO2)/2D Semiconductor (HfSe2) Gate Stack for Low-Power Steep-Switching Computing Devices.

Herein, a high-quality gate stack (native HfO2 formed on 2D HfSe2) fabricated via plasma oxidation is reported, realizing an atomically sharp interface with a suppressed interface trap density (Dit ≈ 5 × 1010 cm-2 eV-1). The chemically converted HfO2 exhibits dielectric constant, κ ≈ 23, resulting in low gate leakage current (≈10-3 A cm-2) at equivalent oxide thickness ≈0.5 nm. Density functional calculations indicate that the atomistic mechanism for achieving a high-quality interface is the possibility of O atoms replacing the Se atoms of the interfacial HfSe2 layer without a substitution energy barrier, allowing layer-by-layer oxidation to proceed. The field-effect-transistor-fabricated HfO2/HfSe2 gate stack demonstrates an almost ideal subthreshold slope (SS) of ≈61 mV dec-1 (over four orders of IDS) at room temperature (300 K), along with a high Ion/Ioff ratio of ≈108 and a small hysteresis of ≈10 mV. Furthermore, by utilizing a device architecture with separately controlled HfO2/HfSe2 gate stack and channel structures, an impact ionization field-effect transistor is fabricated that exhibits n-type steep-switching characteristics with a SS value of 3.43 mV dec-1 at room temperature, overcoming the Boltzmann limit. These results provide a significant step toward the realization of post-Si semiconducting devices for future energy-efficient data-centric computing electronics.

Integration of Ultrathin Hafnium Oxide with a Clean van der Waals Interface for Two-Dimensional Sandwich Heterostructure Electronics.

Integrating high-κ dielectrics with a small equivalent oxide thickness (EOT) with two-dimensional (2D) semiconductors for low-power consumption van der Waals (vdW) heterostructure electronics remains challenging in meeting both interface quality and dielectric property requirements. Here, we demonstrate the integration of ultrathin amorphous HfOx sandwiched within vdW heterostructures by the selective thermal oxidation of HfSe2 precursors. The self-cleaning process ensures a high-quality interface with a low interface state density of 1011-1012 cm-2 eV-1. The synthesized HfOx displays excellent dielectric properties with an EOT of ∼1.5 nm, i.e., a high κ of ∼16, an ultralow leakage current of 10-6 A/cm2, and an impressively high breakdown field of 9.5 MV/cm. This facilitates low-power consumption vdW heterostructure MoS2 transistors, demonstrating steep switching with a low subthreshold swing of 61 mV/decade. This one-step integration of high-κ dielectrics into vdW sandwich heterostructures holds immense potential for developing low-power consumption 2D electronics while meeting comprehensive dielectric requirements.

Innovative Silicon-Ceramic (SiCer) Technology for High-Strength Pressure Sensor Applications Using Different Manufacturing Methods

A variety of manufacturing methods can be used to assemble silicon-based piezoresistive pressure sensors, such as anodic bonding or silicon direct bonding. To achieve highstrength pressure sensors, a high quality interface connection is required. The combination of silicon and ceramic creates a new innovative composite system known as Silicon-on-Ceramics, short SiCer. By using a special developed bondable Low Temperature Co-fired Ceramic tape, which corresponds to the thermal expansion coefficient of Si, the combination of both materials is possible through a sintering process. Advantages of the SiCer technology are high temperature stability, manufacturing at wafer-level and a high bond strength at the interface. Different manufactured SiCer-based pressure sensors were fabricated, electrically and mechanically characterized and compared with anodic bonded and silicon direct bonded pressure sensors.

Evaluating the usability and effectiveness of the Go PainFree telehealth system (beta version) for musculoskeletal pain management in the Philippines

Biomechanical Taping has been shown to effectively reduce pain and enhance function in patients with musculoskeletal pain. When used as an adjunct to physiotherapy, BMT may contribute to increased stability, leading to improved pain management and functionality. Telehealth has emerged as an effective and cost-efficient alternative to traditional physiotherapy. The Go PainFree Telehealth System, employs BMT to alleviate pain and improve functionality, enhancing the overall effectiveness of online therapy services for patients with musculoskeletal conditions.The study determined the usability of the system in managing musculoskeletal conditions for patients accessing healthcare online, focusing on its usefulness, ease of use and learnability, interface quality, interaction quality, reliability, satisfaction, and future use. Also, the study examined the effectiveness of BMT on pain and function in individuals with musculoskeletal conditions when integrated into the system after a single session.This retrospective study reviewed the records of the system between November 2022 and February 2023. Evaluating the system's usability involved the integration of the Telehealth Usability Questionnaire within the system survey, serving as a reliable instrument for assessing the quality of telehealth applications from the users' perspective. Participants rated various parts, including usefulness, ease of use and learnability, interface quality, interaction quality, reliability, and satisfaction and future use. To determine the effectiveness of BMT, the 100-mm Visual Analogue Scale (VAS) was used before and after a single session. Data analysis was conducted using descriptive statistics, allowing for the summarization of demographic information and the reporting of average mean (95 % (CI)) for each usability category of the TUQ. The effectiveness of BMT on pain and function was determined using the Wilcoxon test for paired samples after one session. P < 0.05 indicates significant improvement in pain and function. This study involved 33 participants, with a mean (SD) age of 34.94 ± 2.04, who used the system between November 2022 and February 2023. The majority of reported musculoskeletal conditions pertained to the upper extremity (n = 19), followed by the lower extremity (n = 8), and spine (6). The findings revealed that participants generally considered the system useful, easy to use and learn, and had good interface and interaction quality, as shown by average scores of five in these categories, indicating "somewhat agree." Conversely, participants expressed reservations about the system's reliability, with an average score of 3 reflecting "somewhat disagree." As for their satisfaction with the system and the likelihood of future use, participants showed mixed opinions, with an average score of 4 representing "neither agree nor disagree." The study showed BMT significantly reduced pain scores (Z = −4.80, p < 0.001, two-tailed) and enhanced function scores (Z = −4.87, p < 0.0001, two-tailed) for participants with musculoskeletal conditions.The system was generally regarded by the participants as useful, user-friendly, and characterized by high-quality interface and interaction. Despite these positive perceptions, concerns about the platform's reliability emerged, and opinions about satisfaction and future use were mixed. Still, the integration of BMT into the system yielded significant reductions in pain and improvement in function for the participants with musculoskeletal conditions.

Exploring How LPBF process parameters impact the interface characteristics of LPBF Inconel 718 deposited on Inconel 718 wrought substrates

This work investigates the interface properties of LPBF Inconel 718 deposited on Inconel 718 wrought substrates fabricated using the laser powder bed fusion (LPBF) technique. The as-printed (S1, S2, S3, and S4) samples were characterized using optical microscopy (OM),scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and micro-hardness techniques.The samples showed the development of a melted interface zone (MIZ) at the wrought substrate-deposition interface for all processing conditions. The developed interface showed a dendritic grain structure, signifying the remelting of the wrought substrate followed by rapid solidification. The MIZ thickness increased with an increase in laser power and scan speed (28.5 % increase in the MIZ thickness with a ∼ 12 % increase in normalized enthalpy). The assessment of the MIZ showed a high-quality interface. However, with an increase in scanning speed, the density of the MIZ decreases owing to increased porosity and lack-of-fusion (LOF) defects. The S1 condition (250 W and 850 mm/s) resulted in a highly dense part with no visible porosity, LOF defects, and a high relative density (∼99.9 %) in the MIZ region. The S4 condition showed the presence of large porosities and LOF defects at the deposition-MIZ interface, signifying an inferior bond between the deposition and substrate. The microstructural characterization of the LPBF-processed and MIZ region showed an increase in the primary dendritic arm spacing (PDAS) with increasing laser power due to a reduced cooling rate. The micro-hardness characterization of the sample shows a decrease in the hardness of the MIZ attributed to the dissolution of strengthening phases due to remelting. The present work outcome demonstrates the effectiveness of the proposed methodology for manufacturing high-quality parts using LPBF technology.

Phase-separated stretchable conductive nanocomposite to reduce contact resistance of skin electronics

Skin electronics, facilitating a high-quality interface between external devices and human skin for recording physiological and/or electrophysiological signals as well as delivering external electrical and/or mechanical energy into the human body, has shown significant progress. However, achieving mechanically conformal contact and electrically low contact resistance at the device-skin interface remains challenging. Here, we propose a material strategy to potentially address such an issue by using phase separation of silver nanowires and silver nanoparticles (Ag NWs and Ag NPs) within a stretchable conductive nanocomposite (NC). This phase-separated NC ensures low contact resistance and high conductivity, which are key requirements in skin electronics, while maintaining excellent mechanical contact with the skin. To achieve phase separation, we hydrophobically treated the surfaces of Ag NWs and Ag NPs. Then, as the NC solidified, the solvent contained in the NC was slowly evaporated to sufficiently precipitate Ag NPs within the NC. As a result, the phase-separated NC exhibited high conductivity (~ 18,535 S cm−1), excellent stretchability (~ 80%), and low contact resistance on both the top and bottom NC surfaces (average ~ 0.132 Ω). The phase-separated NC has enabled implementation of high performance skin-mounted devices, including strain sensors, electrophysiological sensors, and a wearable heater.

Pioneering non-thermal plasma as a defect passivator: a new Frontier in ambient metal halide perovskite synthesis.

Growing energy demands make cost-effective, high-performance perovskite solar cells (PSCs) desirable. However, their commercial applications are limited due to defect formation and instability. Passivation technologies help enhance their favorable traits. Herein, we propose a pioneering technique utilizing non-thermal plasma (NTP) synthesis for passivating inherent defects and optimizing the energy levels of perovskites. AC-NTP utilizes ionic charges and uniform electric fields to effectively neutralize defect-induced charge traps, acting as a field-effect passivator. This approach not only mitigates energetic defects, but also facilitates the transformation of NH4PbI3 into a CH3NH3PbI3 perovskite through a self-degassing mechanism. The perovskites synthesized using this method demonstrate notable advancements in their properties, as evidenced by X-ray diffraction, UV-vis spectroscopy, and scanning electron microscopy. These improvements include enhanced crystalline quality, superior optical characteristics, and precise nanoparticle size control, with an average size of 54 nm. In situ Rietveld refinement analysis reveals minimal PbI2 formation, resulting in fewer lead iodide inversion defects. Accordingly, the PSC fabricated by AC-NTP shows a PCE of 15.25%, significantly higher than that fabricated by the DC one (13.29%), which demonstrates improved stability under ambient conditions for over 160 hours. Hysteresis assessment, SCLC analysis, and Shockley diode modeling show our PSCs' low defect densities and high interface quality. Moreover, DFT was applied to indirectly analyze the effects of NTP on the perovskites, focusing on quantum confinement effects and lattice arrangement's influence on the optoelectronic characteristics of MAPbI3 nanoparticles. The findings confirm that NTP synthesis leads to more optimal PSCs, showing notable improvement in photovoltaics.

High-performance flexible photodetectors based on CdTe/MoS2 heterojunction.

Flexible photodetectors have attracted escalating attention due to their pivotal role in next-generation wearable optoelectronic devices. This work presents high-performance photodetector devices based on CdTe/MoS2 heterojunctions, showcasing outstanding photodetecting and distinctive mechanical properties. The MoS2 film was exfoliated from bulk layered MoS2 and covered by a sputtered ultrathin CdTe film (∼8.4 nm) to form a heterojunction. Benefitting from the photovoltaic effect induced by the built-in electrical field near the high-quality interface, the fabricated CdTe/MoS2 heterojunction photodetector can operate as a self-powered photodetector without any external bias voltage, especially showing a high photodetectivity of 5.84 × 1011 Jones, remarkable photoresponsivity of 270.3 mA W-1, fast photoresponse with a rise/fall time of ∼44.8/134.2 μs and excellent bending durability. These results demonstrate that the CdTe/MoS2 heterojunctions could have significant potential for future applications in optoelectronic devices.

Spintronic devices based on topological and two-dimensional materials

Novel quantum materials such as topological materials, two-dimensional materials, create new opportunities for the spintronic devices. These materials can improve the charge-spin conversion efficiency, provide high-quality interface, and enhance the energy efficiency for spintronic devices. In addition, they have rich interactions and coupling effects, which provides a perfect platform for finding new physics and novel methods to control the spintronic properties. Many inspiring results have been reported regarding the research on topological materials and two-dimensional materials, especially the layered topological and two-dimensional magnetic materials, and their heterostructures. This paper reviews the recent achievements of these novel quantum materials on spintronic applications. Firstly the breakthroughs that topological materials have been made in spin-orbit torque devices is introduced, then two-dimensional magnetic materials and their performances in spintronic devices are presented, finally the research progress of topological materials/two-dimensional magnetic materials heterostructures is discussed. This review can help to get a comprehensive understanding of the development of these novel quantum materials in the field of spintronics and inspire new ideas of research on these novel materials.

Перспективы разработки фотоприемных устройств SWIR-диапазона с коллоидными квантовыми точками

Modern infrared (IR) photodetectors based on semiconductor colloidal quantum dots (CQDs), including PbS CQDs deposited on silicon, are considered. The mechanism of photocurrent generation associated with exciton generation in PbS and Si CQDs and their subsequent dissociation at the CQD/Si interface with charge carrier transfer to the electrodes is demonstrated. In order to ensure a high-quality interface of the PbS/Si heterojunction and increased efficiency of photocurrent carrier collection, silicon surface passivation was shown to be necessary. Methods for silicon passivation leading to the highest external quantum efficiency are discussed. An evaluative modeling of the Si/PbS CQD heterojunction with an excitonic peak at 1550 nm is conducted.

Exfoliation of graphite to turbostratic graphene

Here, we exfoliated high-quality turbostratic graphene with a clean interface at a high production rate (10 g h−1) directly from graphite using an industrial-friendly technique i.e. plasma spraying, catching note of its growing global interest. The reduction of the (002) x-ray diffraction peak and the transparent scanning electron microscope image are used to characterize the exfoliation. The thickness of exfoliated graphene layers is measured using an atomic force microscope. Turbostratic nature (twist) in graphene is identified based on the appearance of three Raman combination bands (TS1, TS2, and TS3) between 1800 cm−1 and 2300 cm−1. The twist between the layers is precisely measured using selected area electron diffraction (SAED), and the turbostratic nature is confirmed by observing a moiré pattern utilizing a high-resolution transmission electron microscope. The produced turbostratic graphene exhibited large variability in twist angles (2°–30°) with a visible moiré pattern. The high crystalline quality and clean interface between single layers of graphene were confirmed by the moiré pattern and SAED. Later, we demonstrated the mechanism underlying the twist in our exfoliated graphene, which could open the way for the production of high-quality turbostratic graphene with clean interfaces.

Confined VLS Growth of Single-Layer 2D Tungsten Nitrides.

Two-dimensional (2D) metal nitrides have garnered significant interest due to their potential applications in future electronics and quantum systems. However, the synthesis of such materials with sufficient uniformity and at relevant scales remains an unaddressed challenge. This study demonstrates the potential of confined growth to control and enhance the morphology of 2D metal nitrides. By restricting the reaction volume of vapor-liquid-solid reactions, an enhanced precursor concentration was achieved that reduces the nucleation density, resulting in larger grain sizes and suppression of multilayer growth. Detailed characterization reveals the importance of balancing the energetic and kinetic aspects of tungsten nitride formation toward this ability. The introduction of a promoter enabled the realization of large-scale, single-layer tungsten nitride with a uniform and high interfacial quality. Finally, our advance in morphology control was applied to the production of edge-enriched 2D tungsten nitrides with significantly enhanced hydrogen evolution ability, as indicated by an unprecedented Tafel slope of 55 mV/dec.

(Invited) Metal Halide Perovskite Heterostructures: Synthesis and Fundamental Charge Transfer Studies

Metal halide perovskites are inexpensive semiconductor materials promising for high performance solar cells and light emitting diodes (LEDs) because they are easy to synthesize and tolerant of defects. Fundamental understanding of the factors controlling the carrier transfer mechanisms in heterostructures of halide perovskites is crucial for guiding the synthetic strategies to improve properties and device applications. We developed new methods for synthesizing nanostructures of both three-dimensional (3D) perovskites and two-dimensional (2D) Ruddlesden–Popper (RP) layered perovskites, and using them to create novel and arbitrary heterostructures, such as 2D/3D perovskite, vertical and lateral 2D heterostructures, with high quality interface and tunable band alignments. Various structural characterization and time-resolved spectroscopic methods have been employed to collaboratively study the carrier transfer mechanisms between these well-defined heterostructures of 2D and 3D perovskites. These diverse families of perovskite materials and their nanostructures and heterostructures can enable high performance solar cells, lasers, LEDs, and spintronic applications.

Comparative study of different bonding interactions on the interfacial adhesion and mechanical properties of MXene-decorated carbon fiber/epoxy resin composites

Interfacial adhesion determines the mechanical performance of the carbon fibers-reinforced polymers composites (CFRPs), and different bonding interactions could lead to different degrees of interfacial adhesion and mechanical properties of CFRPs. In order to survey specific influence of different bonding interactions on the interface bonding, further boost the mechanical properties of CFRPs, MXene is decorated onto carbon fiber (CF) surface via Van der Waals force or hydrogen bonds (CF-v-MXene), ionic bonds (CF-i-MXene), and covalent bonds (CF-c-MXene), respectively. Besides, detailed interaction mechanisms of various bonding interactions are also comprehensively investigated. The results indicate that the introduction of MXene is obviously efficient for improving the interface adhesion and mechanical properties of CF/epoxy (CF/EP) composites, and the composites reinforced by CF-c-MXene exhibit the optimal properties. Tremendous improvements of 90.1 % and 110.3 % for the impact strength and interfacial shear strength (IFSS) are achieved compared with the composites reinforced by the unsized CF. The microscopic interfacial structure and fracture failure mode are further observed and analyzed to explore the enhancement mechanisms. This work provides effective guidance and reference for the application of MXene and other similar 2D layered materials, such as Transition Metal Dichalcogenides (TMDCs), to design and manufacture high-quality interface for CFRPs with excellent interfacial and mechanical properties.

Gallium phosphide conformal film growth on in-situ tri-TBP dry-cleaned InGaP/GaAs using atomic hydrogen ALD

Nearly stoichiometric (high P/Ga ratio and low oxygen content) ∼ 20 nm GaP epi-layers were conformally deposited on the side-walls of InGaP layers using an atomic H ALD process with triethyl gallium (TEGa) and tri-tertiary butyl phosphine (tri-TBP). The key for uniform nucleation is an in-situ tri-TBP dry-clean in 40 mTorr Ar and 160 mTorr H2 without acidic wet-clean to generate a particle-free and damage-free InGaP surface which induces local epitaxy growth of homogeneous GaP thin films. The in-situ tri-TBP dry-clean removed the native oxide of InGaP, surface particles, and the residual impurities simultaneously. It is hypothesized that the key to the process is in-situ formation of PHx(C4H9)y surface adsorbates from atomic H and tri-TBP surface reactions. In-situ AES, cross-sectional STEM image, ex-situ XPS, AFM, and EDS confirmed the formation of high-quality GaP thin films on InGaP/GaAs with a high-quality interface and smooth surface morphology.

Enhancing second harmonic generation of monolayer WS2 with edge plasmon

Transition-metal dichalcogenide (TMD) monolayers possess large second-order nonlinear susceptibility and have shown great potentials in on-chip nonlinear optical devices. However, the thickness of TMD monolayers is less than 1[Formula: see text]nm, resulting in a rather low second harmonic generation (SHG) efficiency. In this paper, we propose a physical scheme of enhancing SHG of TMD monolayers with edge plasmon. As a proof of concept demonstration, we constructed a hexagonal gold nanoplates/monolayer WS2 heterostructure with high interface quality. By performing SHG measurements, we show that SHG was enhanced by a factor of about 60. Our results set a foundation for on-chip nonlinear optical applications with TMD monolayers.

Highly stable and encapsulation-microstructural cathode derived by self-pressurization behavior in Na-halides-based all-solid-state batteries

The emerging halide solid electrolytes (SEs) possess superior (electro)chemical oxidation stabilities compared to sulfide SEs, but the understanding on their good compatibility toward oxide active materials needs to be further studied. Here, we develop a type of Zr-doped Na3YbCl6 chloride SEs. The optimized composition gains a high ionic conductivity and broad electrochemical oxidation window. The in situ and ex situ analyses verify that the chloride as ionic additive in the cathode is highly compatible with NaCrO2. Importantly, it is revealed that the volume change in the cathode can act a position effect on the microstructure evolution. It promotes to form a special core-shell-like structure with homogeneous chloride encapsulating NaCrO2 grains. Such a soft intimate contact promotes a uniform ion transport and mitigate (electro)chemo-mechanical stresses. The prerequisites generating this specific microstructure are proposed. The main capacity loss of the assembled all-solid-state Na batteries (ASSNBs) only occurs in the initial dozens of cycles, induced by the irreversible O3→O'3 phase transition in NaCrO2. The chloride additives with a soft feature and high oxidation-stability allow a high-quality interface in the oxide cathode and an excellent cycling stability of the ASSNBs.