Micro & Nano Letters最新文献

The graphene nanoribbon field-effect transistor (GNRFET) is gaining attention as a promising device due to its potential in low-power applications. Recent advancements in GNRFET circuit modeling have highlighted its appropriateness for these applications, primarily because of its distinct material characteristics and ability to scale. The objective of this research is to explore the static and switching behaviors of GNRFETs under numerous conditions and to create a model of their analytical device. The methodology involves developing and simulating the GNRFET model using a numerical quantum transport approach based on the non-equilibrium Green's function (NEGF) formalism. This approach provides a self-consistent solution to the three-dimensional (3D) Poisson equation and the one-dimensional (1D) Schrödinger equation. This research presents an in-depth investigation of the static measurements and switching properties of GNRFETs. The study specifically investigates how the width of the graphene nanoribbon and the scaling of the channel length affect device characteristics. The analysis also considers the impact of different temperature and dielectric materials on the performance of the GNRFETs. From our study, we saw that shortening the channel length from 300–100 nm makes the on-state current density rise from 0.428 × 10³ mA/cm to 3.17 × 10³ mA/cm and the off-state current density rise from 0.045 mA/cm to 19.69 mA/cm. The simulation findings indicate that a reduction in channel length of the GNRFET leads to increased ON-state and OFF-state currents. When the device operates at room temperature using HfSiO4 as a dielectric material, this leads to a significant improvement in the I_on/I_off ratio, resulting in 6 times increase. In addition, our work demonstrates that widening the graphene nanoribbon has a negative effect on the off-state performance of GNRFETs. These observations indicate that it is essential to optimize the width and length of GNRs to achieve high-performance GNRFETs in applications that need low power consumption and rapid speed. The impact of channel size reduction and contact doping concentration on transistor performance must be evaluated for the most effective design, fabrication, and selection of GNRFETs in diverse circuits and applications.

In recent years, water sources have faced growing contamination from heavy metals. Detecting these pollutants is particularly challenging due to their presence in trace concentrations. This study investigates the dispersive solid phase extraction of Cu (II) ions by nanomagnetic@polydopamine/polyaniline core-shell composites (NM@pD/pAN core-shell) from aqueous solutions. The key factors influencing extraction efficiency, including pH, absorbent amount, temperature, adsorption time, and copper ion concentration, were optimised through a multifaceted approach facilitated by the Design experimental software. The NM@pD/pAN core-shell was thoroughly distinguished using methods including SEM, FT-IR spectroscopy, diffraction of X-ray beam, EDX, VSM, TGA, and TEM analysis. Based on the ANOVA results, the CCD model was both reliable and highly notable, exhibiting a p-value below < 0.0001. The findings demonstrate the excellent performance of this technique. With a high Cu (II) ion uptake of 28.57 mg/g and 98.65% removal efficiency, the NM@pD/pAN proved effective in treating aqueous solutions. The data result of equilibrium models were most effectively characterised by the isotherm model of Langmuir, demonstrating a correlation coefficient of 0.98, while kinetic studies supported the model of pseudo-second-order, providing the most suitable fit, achieving a correlation coefficient of 0.99. These findings indicate that NM@pD/pAN core-shell composites have promising applications in water purification operations.

This study reports the fabrication and temperature-dependent electrical characterization of a heterojunction formed by lanthanum(III) hydroxide nanoparticles doped with polyethyleneimine-functionalised nitrogen-doped graphene quantum dots (La(OH)₃NPs/PEI N-GQDs) on n-type silicon (n-type Si). The heterostructure exhibits diode-like behaviour in the 77–400 K temperature range, with rectification exceeding two orders of magnitude and increasing as the temperature decreases, reaching an exceptionally high value above 10⁵ at 77 K. Temperature-dependent diode parameters, including barrier height, series resistance, and ideality factor, are extracted using the thermionic emission model, revealing that barrier height increases and ideality factor decreases with rising temperature. These trends, along with significant deviations from the ideal Richardson behaviour of Schottky diodes, are effectively explained by the Werner–Güttler model, which attributes them to Gaussian spatial inhomogeneities of the barrier arising from interface states and nanocomposite-induced fluctuations. This study highlights the robust rectifying behaviour, excellent cryogenic performance, and wide-temperature applicability of the La(OH)₃NPs/PEI N-GQDs on the Si heterostructure, establishing it as a promising platform for low-power diode applications under extreme thermal conditions.

A novel preparation method based on a hydroxyl radical generation apparatus was developed for the continuous production of graphene/MoS₂ composites. By using different electrolytes—NaCl, CTAB, SDS, SDBS, and Na₂SO₄—composites with distinct and controllable morphologies were obtained. XRD analysis confirmed the successful exfoliation of MoS₂ and graphite and the formation of stable composites, while SEM and TEM revealed morphology variations depending on the electrolyte. XPS measurements showed that the CTAB-prepared sample contained a rarely observed C–Mo bond. Electrical conductivity tests and linear sweep voltammetry (LSV) indicated that the CTAB-prepared composite achieved a 2330% increase in conductivity and a substantially reduced HER overpotential (η₁₀ ≈ −0.63 V vs. RHE) compared to bulk MoS₂. This study demonstrates a green, efficient, and scalable route for producing graphene/MoS₂ composites with tunable morphology, significantly enhanced electrical conductivity, and improved electrocatalytic performance. The approach also holds promise for the large-scale fabrication of high-performance graphene/MoS₂-based materials for conductive and electrocatalytic applications.

Carbon nanotubes exhibit exceptional properties such as high carrier mobility, near-ballistic transport, and nanoscale dimensions, making them promising candidates for next-generation nanoelectronic devices. Understanding the dependency of temperature and dielectric is essential for optimizing the performance of carbon nanotube field effect transistors (CNTFETs). In this study, a numerical simulation model of semiconducting CNTFETs is presented to determine the electrical properties in the ballistic regime. This paper focuses on the impact of temperature and dielectric constant to evaluate the input–output characteristic of CNTFET devices. Moreover, the study investigated the changes in threshold voltage as a function of gate dielectric constant and temperature in the nanometer regime. The findings emphasize the importance of integrating temperature and dielectric constant relationships in the design and optimization of CNTFETs, allowing for their effective incorporation into future electronic applications.

This research focuses on fabricating a nylon honeycomb-structured three-dimensional (3D) filter for grey wastewater treatment using fused filament fabrication (FFF) and evaluating its performance in water treatment. The honeycomb module offered a tortuous pathway for particulate deposition during dead-end and depth filtration. A titanium dioxide (TiO₂) nanoparticle coating was applied via spin coating to enhance clogging effects and contaminant retention. A custom test setup was developed to analyse clogging behavior and estimate the filter lifespan. In dead-end mode, the coated filter achieved up to 85% removal of biochemical oxygen demand (BOD) and 80% removal of chemical oxygen demand (COD) during the first cycle, while depth filtration achieved 80% BOD and 75% COD removal. By the fifth cycle, removal efficiencies decreased to 58% BOD and 50% COD in depth filtration, indicating sustained performance over repeated use. Scanning electron microscopy (SEM) visualized progressive particulate accumulation; Fourier-transform infrared spectroscopy (FTIR) confirmed TiO₂ presence; and energy-dispersive X-ray spectroscopy (EDX) showed increased surface carbon content after filtration. Ultraviolet-visible (UV-Vis) spectroscopy confirmed moderate absorbance reduction at peak wavelengths. However, turbidity and total suspended solids (TSS) remained above acceptable limits (e.g., turbidity > 235 NTU; TSS > 410 mg/L), revealing the need for finer pore sizes or multilayer filtration. Clogging Index (CI) reached 0.45 in dead-end and 0.40 in depth filtration by the fifth cycle. The results demonstrate that this 3D-printed nylon-TiO₂ module provides moderate contaminant removal with rapid clogging kinetics, offering promise for non-potable reuse and decentralized greywater treatment applications.

Doxorubicin (DOX), an anthracycline antibiotic, is widely used to treat a range of solid tumours and haematological malignancies. However, its clinical application in breast cancer is hindered by toxic side effects and the development of multidrug resistance (MDR). Enhancing the selective targeting of DOX and overcoming MDR are critical to improving treatment efficacy. Here, we present a DNA nanoflower (DNF)-based delivery system, designed via rolling circle amplification and multi-primer amplification (MCA), which co-delivers antisense oligonucleotides (ASOs) and DOX to human breast cancer cells (MCF-7). This system, named DNF-ASO@DOX, effectively promotes gene silencing, enhances drug accumulation and significantly inhibits cell proliferation. Furthermore, in vivo studies using mouse models of breast cancer demonstrated potent therapeutic effects, highlighting DNF-ASO@DOX as a promising strategy for enhanced anti-tumour therapy.

Dynamic filtering is crucial in various applications, including imaging, communication, and biological detection. With advancements in micro-nano device fabrication, there is a growing demand for enhanced filtering performance. This paper presents a near-infrared single-wavelength tuneable filter that utilizes polymer-dispersed liquid crystal combined with a Fabry–Perot resonant cavity. The device achieves a transmittance of 99% at 927 nm with a 24 nm full width at half maximum. Utilizing the electro-optical tuneable properties of dielectric layer, the transmission wavelength can be tuned from 913 to 969 nm by altering external voltage to it, resulting in a wavelength shift of 56 nm while maintaining high transmittance. This structure provides a reference for the dynamic control of light sensors and near-infrared dynamic imaging.

The synthesis of superfine silver powder with good dispersity is of great significance for accelerating the development of high-end electronics and photovoltaic products. Herein, a kind of quasi-spherical submicron silver powder prepared by the introduction of gelatin during silver ions reduction is reported. The optimal scheme is determined that the initial pH of gelatin solution is 3 and the mass of gelatin (M_w 50,000—70,000) is 10% of silver nitrate, leading to a mono-disperse silver powder with regular morphology and average particle size of 0.5 µm. In addition, the prepared silver powder can be further combined with polydimethylsiloxane (PDMS) to form a stretchable conductive elastomer (PDMS/Ag elastomer). In unstretched state, the minimum sheet resistance of the elastomer can reach 66 Ω/□ without annealing treatment. Even when the elongation reaches 100%, it still exhibits good conductivity with a sheet resistance of only 13 kΩ/□. The comprehensive performance, mainly referring to stretching and conductivity, is comparable to that of some flexible conductive materials involving silver nanowire or nanocarbon. Thus, this study will demonstrate a new class of silver powder with a potential in flexible electronics.

This research explores the desorption mechanism and thermal stability of octadecyltrichlorosilane (OTS, CH₃(CH₂)₁₇SiCl₃) coating on quartz slides and in alkali-metal vapour cells. The morphological thermal-changes, energy dissipation diversity, and anti-relaxation characteristic of OTS coatings before and after exposure to Cs atoms by Fourier transform infrared spectroscopy, water contact angle measurement, atomic force microscopy imaging, collision energy dissipation analysis, and free induction decay of Cs atoms are measured systematically. The results show that the OTS coatings exhibit the best thermal stability under the specific process conditions, and the homogeneous and dense structure makes the adsorption of alkali-metal atoms more stable, which effectively reduces surface energy dissipation and prolongs the relaxation time of Cs atoms. The study provides certain reference for efficient anti-relaxation coating fabrication and coated cell application.