NANOTECHNOLOGY

Synergistic effect of molybdenum dioxide wrapped nitrogen doped carbon nanotubes in binder-free anodes for enhanced lithium storage properties
Zhang H, Tan Z, Xia Y, Wang C, Pang H, Bai X, Liu H and Khosla A
Molybdenum dioxide (MoO) is regarded as a potential anode for lithium-ion batteries due to its highly theoretical specific capacity. However, its further application in lithium-ion battery is largely limited by insufficient practical discharge capacity and cyclic performance. Here, MoOnanoparticles are in-situ grown on three-dimensional nitrogen doped carbon nanotubes (NCNTs) on nickel foam substrate homogeneously using a simple electro-deposition method. The unique structural features are favorable for lithium ions insertion and extraction and charge transfer dynamics at electrode/electrolyte interface. As a proof of concept, the as-synthesized nanocomposites have been employed as anode for lithium-ion battery, exhibiting a reversible and significantly improved discharge capacity of ∼517 mA h gat the current density of 150 mA gas well as superior cycle and rate performance. The first-principle calculations based on density functional theory and electrochemical impedance spectroscopy results demonstrate a reduced energy barrier of lithium ions diffusion, improved lithium storage behavior, reduced structure collapse, and significantly enhanced charge transfer kinetics in MoO/NCNTs nanocomposites with respect to MoOpowder. The excellent performance makes as-prepared MoO/NCNTs nanocomposites promising binder-free anode for high performance lithium-ion batteries. This work also provides important theoretical insights for other state-of-the-art batteries design.
Thermal conductivity suppression in ZnO with AlZnOand ZnPfor thermoelectric applications
Hsin CL, Liu YT and Tsai YY
In this study, intrinsic ZnO powder was sintered and intercalated with particles. The resulting powder, along with a commercial p-type product, was consolidated into bulk materials, and their thermal conductivity was measured across a temperature range of 350 K to 700 K. The thermal conductivity of the commercial p-type ZnO was found to be lower than that of intrinsic ZnO, attributed to controlled doping. Notably, our demonstration illustrated that the thermal conductivity can be reduced by a factor of 5-10 in the presence of AlZn2O4 and ZnP2 precipitates. This methodology presents a feasible approach for the future design of ZnO-based thermoelectric materials, particularly for thermal heat scavenging applications. .
Flexible pressure sensor with metallic reinforcement and graphene nanowalls for wearable electronics device
Zhang J, Shen H, Mao W, Wang Z, Liao B, Li Y and Wu T
In recent years, flexible pressure sensors have been seen widespread adoption in various fields such as electronic skin, smart wearables, and human-computer interaction systems. Owing to the electrical conductivity and adaptability to flexible substrates, vertical graphene nanowalls (VGNs) have recently been recognized as promising materials for pressure-sensing applications. Our study presented the synthesis of high-quality VGNs via plasma enhanced chemical vapor deposition (PECVD) and the incorporation of a metal layer by electron beam evaporation (EBE), forming a stacked structure of VGNs/Metal/VGNs. Metal nanoparticles attached to the edges and surfaces of graphene nanosheets can alter the charge transport paths within the material to enhance the responsiveness of the sensor. This layered structure effectively fulfilled the requirements of flexible pressure sensors, exhibiting high sensitivity (40.15 kPa-1), low response time (88 ms), and short recovery time (97 ms). The pressure sensitivity remained intact even after 1000 bending cycles. Additionally, the factors contributing to the impressive pressure-sensing performance of this composite were found and its capability to detect human pulse and finger flexion signals was demonstrated, making it a promising candidate for applications of wearable electronics devices. .
Antitumoral action of carvedilol-a repositioning study of the drug incorporated into mesoporous silica MCM-41
Braz WR, de Souza MGM, da Silva LM, de Azevedo CB, Ribeiro AB, Barbosa DCT, Molina EF, de Faria EH, Ciuffi KJ, Rocha LA, Martins CHG, Santiago MB, Santos ALO and Nassar EJ
We have studied repositioning of carvedilol (an antihypertensive drug) incorporated into MCM-41 mesoporous silica. The repositioning proposes a reduction in the slow pace of discovery of new drugs, as well as toxicological safety and a significant reduction in high research costs, making it an attractive strategy for researchers and large pharmaceutical companies. We obtained MCM-41 bysynthesis and functionalized it by post-synthesis grafting with aminopropyltriethoxysilane (APTES) only or with folic acid (FA), which gave MCM-41-APTES and MCM-41-APTES-FA, respectively. We characterized the materials by scanning and transmission electron microscopy, zeta potential (ZP) measurements, Fourier transform infrared absorption spectroscopy, x-ray diffractometry, nitrogen gas adsorption, and CHNS elemental analysis. We quantified the percentage of drug that was incorporated into the MCM-41 materials by thermogravimetric analysis and evaluated their cytotoxic activity in non-tumor human lung fibroblasts and the tumor human melanoma and human cervical adenocarcinoma cell lines by XTT salt reduction (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-arboxanilide). The x-ray diffractograms of the MCM-41 materials displayed low-angle peaks in the 2range between 2° and 3°, and the materials presented type IV nitrogen adsorption isotherms and H2 hysteresis typical of the MCM-41hexagonal network. The infrared spectra, the charge changes revealed by ZP measurements, and the CHN ratios obtained from elemental analysis showed that MCM-41 was amino-functionalized, and that carvedilol was incorporated into it. MCM-41-APTES incorporated 23.80% carvedilol, whereas MCM-41 and MCM-41-APTES-FA incorporated 18.69% and 12.71% carvedilol, respectively. Incorporated carvedilol was less cytotoxic to tumor and non-tumor cells than the pure drug. Carvedilol repositioning proved favorable and encourages further studies aimed at reducing its cytotoxicity to non-tumor cells. Such studies may allow for larger carvedilol incorporation into drug carriers or motivate the search for a new drug nanocarrier to optimize the carvedilol antitumoral activity.
Surface different charge ligands for modulating selenium nanoparticles formation and activating the interaction with proteins for effective anti-Herpes simplex virus l infection
Chen X, Yue J, Xu X, Chen J, Huang X, Huang Y, Yang Y, Li F and Li T
Selenium-based nanoparticles exhibit antiviral activity by directly modulating immune function. Despite recent promising developments in utilizing selenium nanoparticles (Se NPs) against viral infections, the impact of surface ligand charge on the conformation and interaction with viral proteins, as well as the effectiveness of Se NPs in anti-Herpes simplex virus 1 (HSV-1) infection remains unexplored. In this study, three types of selenium nanoparticles (CTAB-Se, PVP-Se, SDS-Se) with distinct surface charges were synthesized by modifying the surface ligands. We found that apart from differences in surface charge, the size, morphology, and crystal structure of the three types of Se NPs were similar. Notably, although the lipophilicity and cellular uptake of SDS-Se with a negative charge were lower compared to positively charged CTAB-Se and neutrally charged PVP-Se, SDS-Se exhibited the strongest protein binding force during interaction with HSV-1. Consequently, SDS-Se demonstrated the most potent anti-HSV-1 activity and safeguarded normal cells from damage. The mechanistic investigation further revealed that SDS-Se NPs effectively inhibited the proliferation and assembly of HSV-1 by powerfully suppressing the key genes and proteins of HSV-1 at various stages of viral development. Hence, this study highlights the significant role of surface ligand engineering in the antiviral activity of Se NPs, presenting a viable approach for synthesizing Se NPs with tailored antiviral properties by modulating surface charge. This method holds promise for advancing research on the antiviral capabilities of Se NPs.
Quantitative theoretical analysis of the electrostatic force between a metallic tip and semiconductor surface in Kelvin probe force microscopy
Ishida N and Mano T
Theoretical analysis of the electrostatic force between a metallic tip and semiconductor surface in Kelvin probe force microscopy (KPFM) measurements has been challenging due to the complexity introduced by tip-induced band bending (TIBB). In this study, we present a method for numerically computing the electrostatic forces in a fully three-dimensional (3D) configuration. Our calculations on a system composed of a metallic tip and GaAs(110) surface revealed deviations from parabolic behavior in the bias dependence of the electrostatic force, which is consistent with previously reported experimental results. In addition, we show that the tip radii estimated from curve fitting of the theory to experimental data provide reasonable values, consistent with the shapes of tip apex observed using scanning electron microscopy. The 3D simulation, which accounted for the influence of TIBB, enables a detailed analysis of the physics involved in KPFM measurements of semiconductor samples, thereby contributing to the development of more accurate measurement and analytical methods. .
Synthesis and magnetic properties of NiCoOurchin-like nanofibers
Nashaat A, Abu El-Fadl A, Nakamura H and Kassem MA
Single-phase NiCo2O4 (NCO) nanoparticles (NPs) with an average particle size of 12 (± 3.5) nm were successfully synthesized as aggregates in urchin-like nanofibers via a hydrothermal route. Magnetization data measured as functions of temperature and magnetic field suggest a superparamagnetic-like behavior at room temperature, a ferrimagnetic transition around a Curie temperature TC ~200 K, and a spin blocking transition at a blocking temperature TB ~90 K, as observed at a field of 100 Oe. The spin blocking nature has been investigated by analyses of the field-dependence of TB in the static magnetization and its frequency-dependence in the ac susceptibility data measured in zero-field cooling regime, both indicate a low-temperature spin glass-like state. Below TB, the coercivity increases monotonically up to 1.7 kOe with decreasing temperature down to 5 K. Our results indicate that the magnetic behavior of NCO NPs, which is mainly determined by the cations' ratio, oxidation states, and site-occupancy, can be controlled by a synthesis in appropriate particle size and morphology.
Development and optimization of metal silicide EUV pellicle for 400W EUV lithography
Choi M, Park C and Hong J
In the extreme ultraviolet lithography (EUVL) process, extreme ultraviolet (EUV) pellicles serve as thin, transparent membranes that shield the photomask (reticle) from particle contamination, thereby preserving photomask pattern integrity, reducing chip failure risks, and enhancing production yields. The production of EUV pellicles is highly challenging due to their mechanical fragility at nanometer-scale thicknesses and the need to endure the rigorous conditions of the EUVL environment, which include high temperatures and hydrogen radicals. Consequently, extensive research has been conducted on a variety of materials, such as carbon-based and silicon-based substances, for the development of EUV pellicles. This study explores the feasibility of implementing metal silicide (MeSi) pellicles for high-power EUVL applications. We successfully fabricated MeSipellicles in two dimensions: a 10 mm × 10 mm sample and a full-size 110 mm × 144 mm pellicle. We then evaluated their optical, mechanical, thermal, and chemical properties, as well as their lifespan. The pellicles demonstrated over 90% transmittance and less than 0.04% reflectance. The films exhibited a deflection of 300m under a 2 Pa differential pressure and an ultimate tensile strength exceeding 2 GPa. The thermal emissivity was measured at 0.3. Additionally, the durability of the pellicles was validated through exposure to 20,000 wafers using a 400 W EUV power (offline test: 20 W cm). The transmittance variations of the pellicles were evaluated by comparing the measurements obtained before and after exposure to 400 W EUV power.
Comparative performance analysis of unmixed and mixed metal oxide sensors for dual-sensing leveraging machine learning
Ramakrishnan B, Savarimuthu K and Emimal M
This paper presents the synthesis of mixed metal oxide (BaTiO3: ZnO) (B: Z) sensors with various molar ratios using a low- temperature hydrothermal method for dual sensing applications (gas and acceleration). The sensor developed with an equal molar ratio of 1B:1Z, showcases superior performance compared to unmixed and alternative mixed metal oxide sensors. This equilibrium in ratios optimally enhances synergistic effects between elements B and Z, resulting in improved sensing properties. Furthermore, it contributes to structural stability, enhancing performance in gas and acceleration sensing. A decreased band gap of 2.82eV and a rapid turn-on voltage of 0.18V were achieved. The acceleration performance of 1B:1Z sensor exhibits a maximum voltage of 2.62 V at a 10 Hz resonant frequency and an output voltage of 2.52 V at 1 g acceleration, achieving an improved sensitivity of 3.889 V/g. In addition, the proposed gas shows a notable sensor response of ~63.45% (CO) and 58.29% (CH4) at 10 ppm with a quick response time of 1.19s (CO) and 8.69s (CH4) and recovery time of 2.09s (CO) and 8.69s (CH4). Challenges in selectivity are addressed using machine learning, employing various classification algorithms. Linear Discriminant Analysis (LDA) achieves superior accuracy in differentiating between CO and CH4, reaching 96.6 % for CO and 74.6 % for CH4 at 10 ppm. Understanding these concentration-dependent trends can guide the optimal use of the sensors in different current applications. .
Mapping nanoparticle formation and substrate heating effects: a fluence-resolved approach to pulsed laser-induced dewetting
Mazón-Martínez A, García-Fernández T, Martinez Fuentes MAA and Sánchez-Aké C
This study investigates the fluence-dependent evolution of gold nanoparticles formed through single nanosecond pulsed laser dewetting of a gold thin film on a fused silica substrate. By employing a well-defined Airy-like laser spatial profile and reconstructing SEM images across the irradiation spot into a panoramic view, we achieve a detailed continuous analysis of the nanoparticle formation process. Our morphological analysis, combined with finite element thermal simulations directly correlated with the applied fluence, identifies two distinct thresholds. The first threshold corresponds to the dewetting of the gold film at its melting point, resulting in large, sparse nanoparticles. The second threshold, where the substrate temperature reaches values near its melting point, leads to the formation of numerous small nanoparticles and a significant increase in coverage area. Notably, the formation of these small nanoparticles is attributed to substrate heating, which alters the interaction between the molten gold film and the substrate, increasing adhesion. Contact angle measurements of the nanoparticles confirm this change, revealing a shift in wettability, and highlighting the crucial role of substrate heating in modulating the interactions leading to nanoparticle formation. Our findings underscore the intricate interplay between laser fluence, material properties, and substrate interactions in pulsed laser dewetting, with the well-defined laser profile offering valuable insights into these dynamics.
Friction-enhanced formation of Cu microwire on Si wafer
Liu C, Song Y, Chai Z, Zeng H, Tian Y and Meng Y
Tribological printing is emerging as a promising technique for micro/nano manufacturing. A significant challenge is enhancing efficiency and minimizing the need for thousands of sliding cycles to create nano- or microstructures (ACS Appl. Mater. Inter. 2018;10:40335-47, Nanotechnology 2019;30:95302). This study presents a rapid approach for forming Cu microwires on Si wafers through a friction method during the evaporation of an ethanol-based lubricant containing Cu nanoparticles. The preparation time is influenced by the volume of the lubricant added, with optimal conditions reducing the time to 300 seconds (600 sliding cycles) for producing Cu microwires with a thickness of 200 nm. Key aspects include the lubricating effect of ethanol on the friction pairs and the role of ethanol evaporation in the growth of Cu microwires. Successful formation requires a careful balance between microwire thickening and wear removal. The resulting Cu microwires demonstrate mechanical and electrical properties that make them suitable as micro conductors. This work provides a novel approach for fabricating conductive microstructures on Si surfaces and other curved surfaces, offering potential applications in microelectronics and sensor technologies.
Quantum dots synthesis within ternary III-V nanowire towards light emitters in quantum photonic circuits: a review
Boras G, Zeng H, Park JS, Deng H, Tang M and Liu H
The positioning of quantum dots (QDs) in nanowires (NWs) on-axis has emerged as a controllable method of QD fabrication that has given rise to structures with exciting potential in novel applications in the field of Si photonics. In particular, III-V NWQDs attract a great deal of interest owing to their vibrant optical properties, high carrier mobility, facilitation in integration with Si and bandgap tunability, which render them highly versatile. Moreover, unlike Stranski-Krastanov or self-assembled QDs, this configuration allows for deterministic position and size of the dots, enhancing the sample uniformity and enabling beneficial functions. Among these functions, single photon emission has presented significant interest due to its key role in quantum information processing. This has led to efforts for the integration of ternary III-V NWQD non-classical light emitters on-chip, which is promising for the commercial expansion of quantum photonic circuits. In the current review, we will describe the recent progress in the synthesis of ternary III-V NWQDs, including the growth methods and the material platforms in the available literature. Furthermore, we will present the results related to single photon emission and the integration of III-V NWQDs as single photon sources in quantum photonic circuits, highlighting their promising potential in quantum information processing. Our work demonstrates the up-to-date landscape in this field of research and pronounces the importance of ternary III-V NWQDs in quantum information and optoelectronic applications. .
Bioactive glass suspension hydrogel promotes wound healing by modulating fibroblasts
Ma K, Chen B, Xu X, Zhang L, Ruan R, Deng H, Zhu X and Zhu H
The irritation and adhesion of wound healing biomaterials to wet wounds should be addressed for achieving effective wound healing. In this study, a stable multifunctional hydrogels (BGs/HA suspension gels) were prepared using superfine powder of bioactive glasses (BGs), the biocompatible materials hyaluronic acid (HA) and carbomer940, which had good adhesion and low irritation properties for use in moist complex wounds. The average particle size of BGs/HA suspension gels was 13.11 ± 0.29 μm, and the bioactive glass content was 15.8 ± 0.2% (m/m). The results of cell proliferation, cell migration, and immunofluorescence staining experiments showed that in the initial stage of wound healing, the ionic extract of BGs formulations promoted the proliferation and migration of L929 cells and induced the secretion of α-SMA and collagen I. In the final stage of repair, the ionic extract of the BGs formulation regulated the differentiation of fibroblast, which contributed to the reduction of pathological scar formation. In vivo experiments showed that the wound healing rate of BGs/HA suspension gels group exceeded higher than that of the conventional BGs superfine powder group. Although BGs/HA suspension gels were comparable to its commercially available counterpart (Dermlin paste) in promoting wound healing, it addressed the problem of localized irritation caused by the high pH and low adhesion of BGs products. This study confirmed the specific regulatory effect of BGs/HA suspension gels on L929 cells, which provided a reference for the clinical application of BGs in wound dressing.
Transport effects of twist-angle disorder in mesoscopic twisted bilayer graphene
Sanjuan Ciepielewski A, Tworzydło J, Hyart T and Lau A
Magic-angle twisted bilayer graphene (TBG) is a tunable material with remarkably flat energy bands near the Fermi level, leading to fascinating transport properties and correlated states at low temperatures. However, grown pristine samples of this material tend to break up into landscapes of twist-angle domains, strongly influencing the physical properties of each individual sample. This poses a significant problem to the interpretation and comparison between measurements obtained from different samples. In this work, we study numerically the effects of twist-angle disorder on quantum electron transport in mesoscopic samples of magic-angle TBG. We find a significant property of twist-angle disorder that distinguishes it from onsite-energy disorder: it leads to an asymmetric broadening of the energy-resolved conductance. The magnitude of the twist-angle variation has a strong effect on conductance, while the number of twist-angle domains is of much lesser significance. We further establish a relationship between the asymmetric broadening and the asymmetric density of states of TBG at angles smaller than the first magic angle. Our results show that the qualitative differences between the types of disorder in the energy-resolved conductance of TBG samples can be used to characterize them at temperatures above the critical temperatures of the correlated phases, enabling systematic experimental studies of the effects of the different types of disorders also on the other properties such as the competition of the different types of correlated states appearing at lower temperatures.
Understanding the competing growth of 2D and 3D transition metal dichalcogenides in a chemical vapor deposition (CVD) reactor
Ullah F, Kazemian S and Fanchini G
The competing growth of two-dimensional (2D) and three-dimensional (3D) crystals of layered transition metal dichalcogenides (TMDCs) has been reproducibly observed in a large variety of chemical vapor deposition (CVD) reactors and demands a comprehensive understanding in terms of involved energetics. 2D and 3D growth is fundamentally different due to the large difference in the in-plane and out-of-plane binding energies in TMDC materials. Here, an analytical model describing TMDC growth via CVD is developed. The two most common TMDC structures produced via CVD growth (2D triangular flakes and 3D tetrahedra) are considered, and their formation energies are determined as a function of their growth parameters. By calculating the associated energies of 2D triangular or 3D tetrahedral flakes, we predict the minimum sizes of the critical nuclei of 2D triangular and 3D morphologies, and thereby determine the minimum realizable dimensions of TMDC, in the form of quantum dots. Analysis of growth rates shows that CVD favors 2D growth of MoS2 between 820 K and 900 K and 3D growth over 900 K. Our model also suggests that the flow rates of TMDC precursors (metal oxide and sulfur) in a long, cylindrical CVD reactor are important parameters for attaining uniform growth. Our model provides a compressive analysis of TMDC growth via CVD. Therefore, it is a critical tool for helping to achieve reproducible growth of 2D and 3D TMDCs for a variety of applications. .
Laser modulation of the FePSmemristors
Chen S, Wang S, Xiong W, Zhou Z, Du X, Ma L, Wang J, Wang C, Zhang X and Liu Q
Ternary two-dimensional (2D) material-based memristors have garnered significant attention in the fields of machine learning, neuromorphic computing due to their low power consumption, rapid learning, and synaptic-like behavior. Although such memristors often exhibit high ON/OFF ratios and exceptional pulse response characteristics, they have also to face some challenges concerning reusability and switching cycles, which arise from the filament instability issues. Here we propose a modulation strategy to improve performance of 2D-material memristors with synaptic and flexible features. By laser-modulating few-layer FePS, we induced the formation of conductive filaments, realized a major improvement in performance of the FePSmemristors, achieving an ON/OFF ratio of nearly 10, low power consumption at approximately 10W of single switching operation, and maintaining stability even after over 500 cycles. The performance promotion has been ascribed to enhancement of conductive filament induced by laser-modulation. Furthermore, we have identified the effectiveness of our laser modulation under strain by building the high-performance flexible FePSmemristor. Meanwhile, we discovered a novel strain-dominant erasure method for the flexible memristors. Our work confirms that laser modulation is a viable method for enhancing the performance of 2D material-based memristive devices.
Carbyne as a promising material for E-nose applications with machine learning
Kucherik A, Kumar A, Andrey A, Samyshkin V, Anton O, Bordanov I, Shchanikov SA and Kumar M
There has been a lot of study and advancement in the area of carbon allotropes in the last several decades, driven by the exceptional and diverse physical and chemical characteristics of carbon nanomaterials. For example, nanostructured forms such as carbon nanotubes, graphene, and carbon quantum dots have the potential to revolutionize various industries [1-3]. The global scientific community continues to research in the field of creating new materials, particularly low-dimensional carbon allotropes such as carbon nanotubes (CNTs) and carbyne. Carbyne is a one-dimensional carbon allotrope with a large surface area, chemical reactivity, and gas molecule adsorption potential that makes it extremely sensitive to gases and electronic nose (E-nose) applications due to its linear sp-hybridized atomic chain structure. The primary objective of this work is to increase the sensitivity, selectivity, and overall efficiency of E-nose systems using a synergistic combination of carbyne-based sensing components with cutting-edge machine learning techniques. The exceptional electronic properties of carbyne, such as its high electron mobility and adjustable bandgap, enable rapid and specific adsorption of various gas molecules. Additionally, its significant surface area-to-volume ratio enhances the detection of trace concentrations. Our suggested advanced hybrid system utilises support vector machines (SVMs) and convolutional neural networks (CNNs) as sophisticated machine learning approaches to analyse data provided by carbyne sensors. These algorithms enhance the precision and durability of gas detection by effectively recognising intricate patterns and correlations in the sensor data. Empirical evidence suggests that E-nose systems based on carbyne have superior performance in terms of reaction time, sensitivity, and specificity compared to conventional materials. This research emphasises the revolutionary potential of carbyne in the advancement of next-generation gas sensing systems, which has significant implications for applications in environmental monitoring, medical diagnostics, and industrial process control. .
Doping- and capacitor-less 1T-DRAM cell using reconfigurable feedback mechanism
Suh Y and Lim D
In this paper, we propose a doping- and capacitor-less 1T-DRAM cell, which achieved virtual doping by leveraging charge plasma and bias-induced electrostatic doping (bias-ED) techniques in a 5 nm-thick intrinsic silicon body, thereby eliminating doping processes. Platinum was in contact with the drain, while aluminum was in contact with the source, enabling virtual doping of the silicon body into a*-* configuration via the charge-plasma technique. Two coupled polarity gates and one control gate are positioned above the intrinsic channel region. The intrinsic channel region is virtually doped through the bias-ED by applying voltages to the gates, forming potential wells inside the channel. The voltage applied to the two coupled polarity gates determines whether the device operates in the- or-channel mode, whereas the control gate governs the flow of charge carriers. Charge carriers are stored and released in the potential wells inside the channel by adjusting the gate, effectively replacing the capacitor. In this device, the placement of polarity gates on either side of the control gate enables the observation of the reconfigurable characteristics. Moreover, the proposed device utilizes a feedback mechanism, enabling excellent memory characteristics such as a high on/off current ratio of ∼10, steep switching behavior of ∼0.2V dec, short write time of 10 ns, long hold retention of over 100 s, and long read retention of over 600 s.
Shallow defects and optical properties of CsPbBrthin films through noble gas ion beam defect engineering
Fiedler H, Hardy J, Halpert JE, Davis NJLK and Kennedy J
Ion implantation is widely utilised for the modification of inorganic semiconductors; however, the technique has not been extensively applied to lead halide perovskites. In this report, we demonstrate the modification of the optical properties of caesium lead bromide (CsPbBr) thin films via noble gas ion implantation. We observed that the photoluminescence (PL) lifetimes of CsPbBrthin films can be doubled by low fluences (<1 × 10at·cm) of ion implantation with an acceleration voltage of 20 keV. We attribute this phenomenon to ion beam induced shallow minority charge carrier trapping induced by nuclear stopping, dominant by heavy noble gases (Ar, Xe). Simultaneously, the PL quantum yield (PLQY) is altered during noble gas ion implantation inversely correlates with the electronic stopping power of the implanted element, hence Ar implantation reduces the PLQY, while Ne even causes a PLQY enhancement. These results thus provide a guide to separate the effect of nuclear and electronic damage during ion implantation into halide perovskites.
A novel sensing probe based on AuNPs-Apt for the detection of enrofloxacin
Ding L, Wang P, Xiao B, Gao Z, Zhang D, Che T, Zuo J and Li Y
Enrofloxacin (ENR), as a synthetic broad-spectrum antibiotic is widely utilized in veterinary medicine to treat animal diseases and promote livestock growth, it can inhibit bacterial DNA gyrase subunit A, thereby preventing bacterial DNA replication and exerting its antibacterial effect. However, excessive use of enrofloxacin poses significant risks to ecological balance and human health due to residual contamination. We have developed a novel ENR aptamer sensor based on the gold nanoparticles/aptamer (AuNPs-Apt) complexes, in which AuNPs were synthesized via the seed method and functionalized with aptamers. The optical properties, particle size, functional groups and morphology of the AuNPs-Apt probe were characterized by transmission electron microscope, Fourier transform infrared spectrometer and UV-vis spectrophotometer, respectively. The aptamer biosensor can specifically identify enrofloxacin, with a wide detection range (0.05-100g ml) and a good linear relationship (R2=0.99) within the detection range. In addition, the biosensor also has the advantages of short detection time, low biological toxicity, good stability, and low detection cost. Therefore, it shows a great prospect for practical application in the field of detecting enrofloxacin residues.
First principles electron transport in magnetoelectric SrRuO/BaTiO/SrTiO/SrRuOinterfaces
Filipoiu N, Plugaru N, Sandu T, Plugaru R and Nemnes GA
Recently, all-oxide ferroelectric tunnel junctions, with single or composite potential barriers based on SrRuO/BaTiO/SrTiO(SRO/BTO/STO) perovskites, have drawn a particular interest for high density low power applications, due to their highly tunable transport properties and device scaling down possibility to atomic size. Here, using first principles calculations and the NEGFs formalism, we explore the electronic structure and tunneling transport properties in magnetoelectric SRO/BTO/STO/SRO interfaces, (= 0, 2, or 4 unit cells), considering both the RuOoctahedra tilts and magnetic SRO electrodes. Our main results may be summarized as follows: i) The band alignment schemes predict that polarization direction may determine both Schottky barrier or Ohmic contacts for(STO)=0, but only Schottky contacts for(STO)=2 and 4 junctions; ii) The tunnel electroresistance and tunnel magnetoresistance ratios are evaluated at 0 and 300 K; iii) The most magnetoelectric responsive interfaces are obtained for the(STO)=2 heterostructure, this system also showing co-existent giant tunnel electroresistance and tunnel magnetoresistance effects; iv) The interfacial magnetoelectric coupling is not strong enough to control the tunnel magnetoresistance by polarization switching, in spite of significant SRO ferromagnetism.