Properties Of Devices Research Articles

Surface Characterization of Bone-Level and Tissue-Level PEEK and Titanium Dental Implant Scan Bodies After Repeated Autoclave Sterilization Cycles

Background: Sterilization is required for any biomedical device intended to be used in contact with the human body. Several studies have reported alterations in the bulk and surface properties of such devices after repeated sterilization cycles. These surface modifications may influence other clinical parameters. Therefore, the aim of this study was to investigate the surface and chemical properties of implant scan bodies (SBs) after consecutive autoclave sterilization procedures. Methods: The objective was to analyze the scan bodies using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) for chemical analysis and an optical profilometer to analyze the surface roughness. Results: FTIR spectra depicted the appearance of peak at 1741 and 1100 cm−1 due to the diphenyl ether band disappearance. The XPS spectra showed alterations in the elemental composition after autoclaving and roughness were significantly reduced in PEEK BL and TL SBs. Conclusions: These results indicated that some surface modifications were induced by repeated sterilization cycles.

Materials Nanoarchitectonics for Advanced Devices

Advances in nanotechnology have made it possible to observe and evaluate structures down to the atomic and molecular level. The next step in the development of functional materials is to apply the knowledge of nanotechnology to materials sciences. This is the role of nanoarchitectonics, which is a concept of post-nanotechnology. Nanoarchitectonics is defined as a methodology to create functional materials using nanounits such as atoms, molecules, and nanomaterials as building blocks. Nanoarchitectonics is very general and is not limited to materials or applications, and thus nanoarchitecture is applied in many fields. In particular, in the evolution from nanotechnology to nanoarchitecture, it is useful to consider the contribution of nanoarchitecture in device applications. There may be a solution to the widely recognized problem of integrating top-down and bottom-up approaches in the design of functional systems. With this in mind, this review discusses examples of nanoarchitectonics in developments of advanced devices. Some recent examples are introduced through broadly dividing them into organic molecular nanoarchitectonics and inorganic materials nanoarchitectonics. Examples of organic molecular nanoarchitecture include a variety of control structural elements, such as π-conjugated structures, chemical structures of complex ligands, steric hindrance effects, molecular stacking, isomerization and color changes due to external stimuli, selective control of redox reactions, and doping control of organic semiconductors by electron transfer reactions. Supramolecular chemical processes such as association and intercalation of organic molecules are also important in controlling device properties. The nanoarchitectonics of inorganic materials often allows for control of size, dimension, and shape, and their associated physical properties can also be controlled. In addition, there are specific groups of materials that are suitable for practical use, such as nanoparticles and graphene. Therefore, nanoarchitecture of inorganic materials also has a more practical aspect. Based on these aspects, this review finally considers the future of materials nanoarchitectonics for further advanced devices.

DC and RF Performance Optimization of Source Pocket Designed Hybrid-Dielectric Vertical Nanowire Tunnel-FET: Low Power Perspective

This article addresses a new source pocket designed hybrid-dielectric vertical nanowire tunnel-FET (SP-HD-VNW-TFET). The existence of a source pocket at the source and channel boundary is shown such that the potential barrier at the tunnel-junction is minimized which causes ON current to rise. This article studied a comparison between a SP-HD-VNW-TFET device and source pocket vertical nanowire tunnel field effect transistor (SP-VNW_TFET). Using a hetero/hybrid-dielectric material boosts the electric field, resulting in higher tunneling current (1.72 × 10−6 A μm−1). The device has undergone detailed investigation of both DC and AC characteristics like On-current, Off-current, ION/IOFF, Subthreshold-swing, VT, gm, fT, GWB, and TFP. Source Pocket engineering and Hybrid dielectric inclusion increase device properties, including on-current and subthreshold swing (SS). The device’s electrical properties have been evaluated and compared using the Sentaurus TCAD Tool.

Investigation of the Impact of Clitoria ternatea Dye on the Growth and Characterization of Lithium Paranitrophenolate Trihydrate Single Crystals for Nonlinear Optical Applications

Incorporating dyes into crystalline structures has emerged as a promising strategy for enhancing material properties in solid-state devices. In this study, a single crystal of lithium p-nitrophenolate trihydrate (LiPNPT) doped with Clitoria ternatea L. (CT) flower dye was successfully synthesized and its properties were compared with those of undoped LiPNPT crystals. Energy-dispersive X-ray spectroscopy (EDAX) confirmed the elemental composition while single crystal X-ray diffraction (XRD) elucidated the structural properties. The optical characteristics were evaluated using UV-Visible and Photoluminescence analyses. Fourier-transform infrared (FTIR) and FT-Raman spectroscopy provided insights into the vibrational modes and molecular interactions. The CT-LiPNPT crystal exhibited enhanced thermal stability, mechanical strength and a higher decomposition temperature compared to the undoped crystal. Dielectric studies were conducted to assess the electrical properties. Notably, the second-harmonic generation (SHG) efficiency of the CT-LiPNPT crystal was 2.39 times higher than that of the undoped crystal and showed a higher laser damage threshold. Z-scan analysis revealed significant third-order nonlinear optical properties and optical limiting behavior in the doped crystal. These comprehensive investigations demonstrate that the CT dye-doped LiPNPT possesses improved characteristics, rendering it a more reliable candidate for optoelectronic and nonlinear optical device applications.

Direct Imaging of Asymmetric Interfaces and Electrostatic Potentials inside a Hafnia-Zirconia Ferroelectric Nanocapacitor.

In hafnia-based thin-film ferroelectric devices, chemical phenomena during growth and processing, such as oxygen vacancy formation and interfacial reactions, appear to strongly affect device performance. However, the correlation between the structure, chemistry, and electrical potentials at the nanoscale in these devices is not fully known, making it difficult to understand their influence on device properties. Here, we directly image the composition and electrostatic potential with nanometer resolution in the cross section of a nanocrystalline W/Hf0.5Zr0.5O2-δ (HZO)/W ferroelectric capacitor using multimodal electron microscopy. This reveals a 1.4 nm wide tungsten suboxide interfacial layer formed at the bottom interface during fabrication, which introduces a potential dip and leads to asymmetric switching fields. Additionally, we compare the measured potentials to DFT calculations and find it is nearly 3 V lower than expected in the HZO, which appears to be caused by oxygen vacancies and a resulting negative built-in potential. These chemical and electrostatic details are important to characterize and tune to achieve high-performance ferroelectric devices.

Surface-Functionalised Copper Oxide Nanoparticles: A Pathway to Multidrug-Resistant Pathogen Control in Medical Devices

Copper oxide nanoparticles (CuONPs) offer promising antimicrobial properties against a range of pathogens, addressing the urgent issue of antibiotic resistance. This study details the synthesis of glutamic acid-coated CuONPs (GA-CuONPs) and their functionalisation on medical-grade silicone tubing, using an oxysilane bonding agent. The resulting coating shows significant antimicrobial activity against both Gram-positive and Gram-negative bacteria, including multidrug-resistant strains, while remaining non-toxic to human cells and exhibiting stable adherence, without leaching. This versatile coating method can be applied during manufacturing, or for ad hoc modifications, enhancing the antimicrobial properties of medical devices.

Optimization of NC-LSPR coupled MoS2 phototransistors for high-performance broad-spectrum detection

Abstract In this work, negative-capacitance (NC) and local surface plasmon resonance (LSPR) coupled MoS2 phototransistors with a gate stack of HZO/AuNPs/Al2O3/MoS2 are fabricated, and the impacts of Al2O3 interlayer-thickness (T AlO) on the LSPR effect, the tensile strain on MoS2 from the Au nanoparticles (AuNPs), the capacitance matching of the NC effect from Hf0.5Zr0.5O2 (HZO) ferroelectric layer and the optoelectrical properties of the relevant devices are investigated. Through optimizing T AlO, excellent optoelectrical properties of phototransistors with a T AlO of 3 nm are achieved: a subthreshold swing (SS) of 25.76 mV/dec and ultrahigh detectivity of over 1014 Jones under 740 nm illumination. This is primarily because the NC-LSPR coupled structure can achieve an ultra-low SS through capacitance matching and a good interface passivation through optimizing Al2O3 interlayer to maintain effective LSPR and strain effects cross the MoS2 to enhance optical absorption and detection range. This work provides a comprehensive analysis on effective distance range of the non-direct-contacted LSPR effect and its combination with capacitance matching of NC effect, culminating in an optimized NC-LSPR coupled MoS2 phototransistor with a good consistency across an array of 30 devices, and offering a viable solution for the preparation of large-area, high-performance and broad-spectrum response 2D phototransistor array.

Upconversion on the Micrometer Scale: Impact of Local Heterogeneity.

The properties of perovskite/naphtho[2,3-a]pyrene (NaPy) upconversion devices are investigated by a combination of atomic force microscopy and photoluminescence mapping to understand the role of microscopic heterogeneity in the ensemble device properties. The results emphasize strong microscopic inhomogeneity across the perovskite/NaPy upconversion device due to local formation of NaPy microcrystals. NaPy shows emission from three distinct states in the solid state: S1' emission at 520 nm, excimer emission at 560 nm, and S1″ emission at 620 nm. Clear spatial differences in the emission spectrum under 405 nm excitation are found, highlighting that there is a strong microcrystal-to-microcrystal variation in the optical properties─emphasizing a need for multimodal measurements. Our results indicate that microcrystals with strong emission from the strongly coupled low-energy state S1″ (J-dimer) show much higher upconversion intensity than those with dominant emission from the high-energy S1' state (I-aggregate). Hence, our results suggest that microcrystals with strong emission from the low-energy state S1″ act as isolated hotspots for upconversion.

Progress in MOFs and MOFs-Integrated MXenes as Electrode Modifiers for Energy Storage and Electrochemical Sensing Applications.

The global energy demand and environmental pollution are the two major challenges of the present scenario. Recently, researchers focused on the preparation and investigation of catalysts for their capacitive properties for energy storage devices. Thus, supercapacitors have received extensive interest from researchers due to their promising energy storage features and decent cyclic stability/performance. The performance of the supercapacitors are significantly influenced by the physicochemical properties of the electrocatalyst. In this review article, we have compiled the previous reports on the fabrication of MOFs-based composite materials with MXenes for energy storage and electrochemical sensing applications. The metallic and bimetallic MOFs and MOFs/MXenes materials for supercapacitor applications are reviewed. In addition, MOFs/MXenes-based hybrid composites are also compiled towards the determination of various toxic/hazardous materials, such as metal ions like copper ions, mercury ions, and picric acid. We believe that present review article may benefit the researchers working on the preparation of MOFs-based catalysts for supercapacitor and electrochemical sensing applications.

Ultra‐Low Power Photosynaptic Devices Based on Persistent Photoconductivity‐Modulated SnO2

AbstractRealizing visual perception performance using robust metal oxide devices is highly desirable for brain‐inspired neuromorphic computing, visual prosthetics, and artificial intelligence. SnO2, a representative transparent semiconductor, has attracted considerable attention for its potential in ultraviolet photodetectors and photosynaptic devices operating in solar‐blind spectral ranges. This problem has been circumvented by lowering the electron concentration and reducing the persistent photoconductivity (PPC), one of the essential properties of photosynaptic devices. In this case, the electron concentration and PPC properties in SnO2 must be controlled independently. This paper reports the successful control of PPC in SnO2 by controllable addition of Zn and Sr ions, which act as acceptors to annihilate the charge carriers and as a reductant to form oxygen vacancies, respectively. Zn and Sr‐added SnO2 exhibits superior synaptic performance with low energy consumption, successfully imitating the biological synapses without a gate electrode. As a result, the PPC remains at about 40% even after 20 seconds of turning off the ultraviolet light, and energy consumption is reduced to 1–10 fJ, similar to energy consumption with biological synapses. A novel optical sensor that can receive analog signals is demonstrated using a photosynaptic device with Zn and Sr‐added SnO2 thin films.

Numerical Simulation of Autoresonant Ion Oscillations in an Anharmonic Electrostatic Trap.

This work presents the results of modeling the ion dynamics in the ART-MS (Autoresonant Trap Mass Spectrometry) device in the quasi-static approximation. This instrument utilizes an anharmonic, purely electrostatic trap for ion confinement and a radio frequency (RF) voltage source with decrementally varying frequency for selective ion extraction. The autoresonant interaction between the oscillatory motion of the ion and the RF voltage increases the amplitude of some confined ions, allowing their selective extraction. Numerical modeling shows that the extraction of ions with a given mass occurs not only at the fundamental frequency but also at its harmonics. This effect reduces the selective properties of devices of this type because along with the main mass component for a given frequency, it is possible to enter the detector channel of ions with another mass, for which this frequency corresponds to the second or higher harmonics, even a superposition of some of these harmonics of different ions.

Neuroimmune cross-talk in heart failure.

Heart failure (HF) is characterized by autonomic nervous system (ANS) imbalance and low-grade chronic inflammation. The bidirectional relationship between the ANS and immune system (IS) is named "neuroimmune cross-talk" (NICT), and is based on common signaling molecules, receptors, and pathways. NICT may be altered in HF, and neuroinflammation seems to be a main driver of HF progression. In HF, heightened sympathetic nerve activity triggers inflammatory cascades that lead to cardiomyocyte death and myocardial interstitial fibrosis. Concurrently, parasympathetic withdrawal may impair the cholinergic anti-inflammatory pathway, with a less effective immune response to infections or inflammatory events. Additionally, microglial activation and inflammatory molecules contribute to autonomic imbalance by acting on central nuclei and peripheral visceral feedbacks, which in turn promote adverse cardiac remodeling, HF decompensation, and potentially life-threatening arrhythmias. Therefore, neuroinflammation has been identified as a potential target for treatment. Pharmacological antagonism of the neurohormonal system remains the cornerstone of chronic HF therapy. While some drugs used in HF management may have additional benefits due to their anti-inflammatory properties, clinical trials targeting inflammation in patients with HF have so far produced inconclusive results. Nevertheless, considering the pathophysiological relevance of NICT, its modulation seems an appealing strategy to optimize HF management. Current research is therefore investigating novel pharmacological targets for anti-inflammatory drugs, and the immunomodulatory properties of denervation approaches and bioelectronic medicine devices targeting NICT and neuroinflammation in HF. A deeper understanding of the complex relationship between the ANS and IS, as outlined in this review, could therefore facilitate the design of future studies aimed at improving outcomes by targeting NICT in patients with HF.

Insights from Theoretical Modeling of Cesium-Formamidinium-Based Mixed-Halide Perovskite Solar Cells for Outdoor and Indoor Applications.

This study presents an in-depth computational analysis of hybrid organic-inorganic lead halide perovskite solar cells (PSCs) with a composition of Cs0.17FA0.83Pb(Br0.4I0.6)3 (FA: formamidinium) material under cool and warm light-emitting diodes (LEDs). We propose a novel design of an inverted (p-i-n) PSC to compare the power conversion efficiencies (PCEs) of opaque and semitransparent models under the AM1.5G spectrum and indoor LED lighting. The Shockley-Queisser (SQ) limits were estimated for LEDs with color temperatures of 3000 and 6000 K, revealing significant differences in PCE compared to standard solar radiation. The optical and electrical properties of the perovskite devices were simulated by using the transfer-matrix method and one-dimensional drift-diffusion model. We report a PCE of 15.8% for opaque devices under the AM1.5G spectrum, while the semitransparent devices exhibit PCEs of 12.07% and 10.17% for front and rear illumination, respectively. Under indoor conditions with cool LED lighting, the opaque devices demonstrate a significantly higher PCE of 28.38% and an impressive photovoltage of 1.17 V, surpassing the semitransparent devices, which show efficiencies of approximately 19.5% (front illumination) and 18.3% (rear illumination). While the interface between the hole transport layer and perovskite has a major impact on the device performance of opaque solar cells, the perovskite/electron transport layer junction plays a more critical role in the performance of semitransparent solar cells. The power densities for opaque devices reached up to 106.25 μW/cm2 under cool LED and 97.1 μW/cm2 with warm LED illumination. For semitransparent devices, the power densities exceeded 60.71 μW/cm2 on front-side illumination and 73.66 μW/cm2 on rear illumination under cool LEDs. These results emphasize the significant potential of hybrid PSCs for efficient energy harvesting under various lighting conditions, making them promising candidates for powering low-energy-consumption electronics in indoor environments.

Self-consistent quasiparticle GW and hybrid functional calculations for Al/InAs/Al heterojunctions: Band offset and spin-orbit coupling effects

The electronic structure of surfaces and interfaces plays a key role in the properties of quantum devices. Here, we study the electronic structure of realistic Al/InAs/Al heterojunctions using a combination of density functional theory with hybrid functionals and state-of-the-art quasiparticle GW (QSGW) calculations. We find a good agreement between QSGW calculations and hybrid functional calculations, which themselves compare favorably well with angle-resolved photoemission spectroscopy experiments. Our paper confirms the need for well-controlled quality of the interfaces to obtain the needed properties of InAs/Al heterojunctions. A detailed analysis of the effects of spin-orbit coupling on the spin splitting of the electronic states shows a linear scaling in k space, related to the two-dimensional nature of some interface states. The good agreement by QSGW and hybrid functional calculations opens the door towards trustable use of an effective approximation to QSGW for studying very large heterojunctions. Published by the American Physical Society 2024

A hole-selective hybrid TiO2 layer for stable and low-cost photoanodes in solar water oxidation

The use of conductive and corrosion-resistant protective layers represents a key strategy for improving the durability of light absorber materials in photoelectrochemical water splitting. For high performance photoanodes such as Si, GaAs, and GaP, amorphous TiO2 protective overlayers, deposited by atomic layer deposition, are conductive for holes via a defect band in the TiO2. However, when coated on simply prepared, low-cost photoanodes such as metal oxides, no charge transfer is observed through amorphous TiO2. Here, we report a hybrid polyethyleneimine/TiO2 layer that facilitates hole transfer from model oxides BiVO4 and Fe2O3, enabling access to a broader scope of available materials for practical water oxidation. A thin polyethyleneimine layer between the light absorber and the hybrid polyethyleneimine/TiO2 acts as a hole-selective interface, improving the optoelectronic properties of the photoanode devices. These polyethyleneimine/TiO2 modified photoanodes exhibit high photostability for solar water oxidation over 400 h.

Surprisingly fast self-healing coatings with anti-fog and antimicrobial activities via host-guest interaction

Dual functional coatings with anti-fog and antimicrobial performances greatly enhance the safety and reliability of medical detection devices, but are prone to mechanical damage, resulting in reduced performance and a shorter service lifespan. Herein, a semi-interpenetrating polymer network (SIPN) coating, featuring hydrophobic-hydrophilic balanced copolymers as bulk chains and host–guest inclusion compounds (HGICs) as cross-linkers, is reported, which demonstrates particularly effective anti-fog and antibacterial performances, along with a surprisingly fast self-healing capability under various scenarios. This HGIC-based coating displayed remarkable anti-fog capability over a wide temperature range from −20 ℃ to 85 ℃ and exhibited reliable antibacterial activities (≥98 %) against both gram-positive and gram-negative bacteria. Also, this coating showed extremely high self-healing ability (≥92 % recovery rate) within just 20 s, significantly outperforming traditional self-healing systems. These findings support the development of functional coatings that can highly maintain rapid self-healing performance while also providing anti-fog and antibacterial properties in medical detection devices.

Coherent Epitaxy of HfxZr1-xO2 Thin Films by High-pressure Magnetron Sputtering

Due to remarkable high-k and ferroelectric properties in CMOS devices, the study of crystalline HfxZr1-xO2 (HZO) thin films has attracted tremendous interest recently. However, up to now, the epitaxial growth of HZO films has only been achieved by pulse laser deposition, a technique scarcely utilized in CMOS devices. Therefore, developing appropriate epitaxial methods of HZO films (such as sputtering) is fairly necessary, but a challenge at present. In this work, high-quality single-crystalline HZO films were synthesized by high-pressure magnetron sputtering. The epitaxial growth of HZO films on yttria-stabilized zirconia (YSZ) substrate was demonstrated by a combination of high-resolution X-ray diffraction, atom force microscope, and scanning transmission electron microscope. In addition, good insulating characteristics were obtained by replacing insulating substrates with conductive substrates as electrodes. Our results provide a novel way for the epitaxial growth of the single-crystalline structure of HZO thin films towards the high performance of high-k and ferroelectric devices.

Impact of PECVD deposition on dielectric charge and passivation for n-GaN/SiO[formula omitted] interfaces

Controlling properties of GaN/dielectric interfaces is crucial for determining the characteristics of MOS-HEMT devices and their stability. Interface properties are largely affected by the techniques and specific conditions of dielectric deposition. In this work, a Taguchi design of experiment was applied to study the effect of plasma parameters during deposition of SiOx by PECVD for passivation of n-GaN. SiOx/GaN MIS capacitors were fabricated and characterized by capacitance measurement at a high probing frequency of 1 MHz. The interface states density, hysteresis and flatband voltage were analyzed and modeled in relation with the flow of SiH4, plasma power, chamber pressure and temperature. Excellent fits could be obtained on a single model including linear terms for all studied parameters and quadratic terms for the flow of SiH4 and temperature. We show that it is possible to obtain some control of the flatband voltage while maintaining a good interface quality. Positive flatband voltages are potentially of interest to enable normally-off operation for MOS-HEMTs and this could be obtained mainly by using a high SiH4/N2O ratio. To the contrary, negative flatband voltage values often ensure the most stable operation of MOS-HEMTs and this was achieved with a low SiH4/N2O and high plasma power. MIS capacitors with near-zero flatband voltage were also obtained with low SiH4/N2O ratio and low plasma power. Hysteresis and interface states density in relation with deposition plasma conditions are also analyzed in order to offer the best trade-offs depending on the end applications of MOS-GaN devices. By demonstrating the great impact of plasma conditions during dielectric deposition on electronic properties of MIS devices, we show that the process of gate insulation can be optimized to simultaneously control the density of defects and fixed charge at the interface.

Electronic and transport properties of Ti3C2O2-based strain sensor: A DFT-NEGF study

MXenes used as strain sensing materials have recently roused extensive interest due to their two-dimensional structures and outstanding electric properties. However, theoretical analysis from a quantum perspective is relatively scarce, which may hinder the development of this emerging field. Based on density functional theory with non-equilibrium Green’s function, we explored the structure, electronic, and transport properties of Ti3C2O2 with and without biaxial strains. The Ti3C2O2 monolayer remained stable under 5% biaxial strain. The structures and electronic properties of Ti3C2O2 showed gradual evolutions tuned by strain. Moreover, we studied the intrinsic device properties by constructing two-probe devices. The current of the 5% biaxially strained device increased by about 80% compared with the unstrained device. Given the results mentioned earlier, the Ti3C2O2-based nanodevices have the prospect of being strain sensors.

Mott resistive switching initiated by topological defects

Avalanche resistive switching is the fundamental process that triggers the sudden change of the electrical properties in solid-state devices under the action of intense electric fields. Despite its relevance for information processing, ultrafast electronics, neuromorphic devices, resistive memories and brain-inspired computation, the nature of the local stochastic fluctuations that drive the formation of metallic regions within the insulating state has remained hidden. Here, using operando X-ray nano-imaging, we have captured the origin of resistive switching in a V2O3-based device under working conditions. V2O3 is a paradigmatic Mott material, which undergoes a first-order metal-to-insulator phase transition together with a lattice transformation that breaks the threefold rotational symmetry of the rhombohedral metallic phase. We reveal a new class of volatile electronic switching triggered by nanoscale topological defects appearing in the shear-strain based order parameter that describes the insulating phase. Our results pave the way to the use of strain engineering approaches to manipulate such topological defects and achieve the full dynamical control of the electronic Mott switching. Topology-driven, reversible electronic transitions are relevant across a broad range of quantum materials, comprising transition metal oxides, chalcogenides and kagome metals.