Nanotechnology最新文献

ZnO, anintrinsic n-typesemiconductor, has attracted considerable attention in optoelectronics. However, its application in broadband photoresponsivity is limited by its wide band gap. In this study, polyol-synthesized silver nanoparticles (Ag NPs) with controlled size were used to enhance the performance of n-type ZnO nanorods (NRs) and p-type Si heterojunction (ZnO NRs/Si) photodetectors (PDs). Photoluminescence spectra confirmed that the broadband emissions of the ZnO NRs, originating from crystal defects, efficiently overlapped with the localized surface plasmon resonance of the Ag NPs. Under illumination and a reverse bias voltage of 4.0 V, the photocurrent (I_ph) of the detectors increased from 2.2 × 10^-5-2.39 × 10^-4after Ag NP decoration of the ZnO NRs. TheI_ph/I_darkratio of the pristine ZnO NRs/Si device was determined to be 5.5, which increased to 100 in the presence of the Ag NPs. The plasmonic-enhanced PD (Ag-decorated ZnO NRs/Si) exhibited broader and stronger spectral photoresponsivity from the UV-Vis to the NIR range. Responsivity and detectivity values of 0.39 A W^-1and 2 × 10^-11cm.Hz^1/2W^-1at 372 nm, and 0.42 A W^-1and 4.2 × 10^-11cm.Hz^1/2W^-1at 420 nm, were observed for this device. Overall, plasmon-enhanced ZnO NRs/Si PDs demonstrated enhanced broadband UV-Vis-NIR spectral response with high photocurrent values.

Herein, Co-MOF arrays were used as a precursor to fabricate hierarchical catalysts. Heterostructure Co-MOF/Co(OH)₂and Co(OH)₂micro-nano sheet arrays were fabricated by etching treatment in ultrapure water for different time. When treated for 60 min, infrared spectrum and x-ray diffraction (XRD) pattern indicate that there is the co-existence of Co-MOF and Co(OH)₂. After etching for 120 min, the scanning electron microscopy image reveals three-dimensional hierarchical micro-nano sheet arrays, the energy dispersive x-ray spectrum and XRD analysis indicate pure Co(OH)₂phase with high crystallinity. Their glucose sensing performance is systematically explored by cyclic voltammetric and amperometrici-tcurves. The linear ranges of Co-MOF/Co(OH)₂and Co(OH)₂micro-nano sheet arrays are 0.05-2.2 mM (R²= 0.999) and 0.05-5.8 mM (R²= 0.999), their corresponding sensitivities are 1040μA mM^-1cm^-2and 884μA mM^-1cm^-2, respectively. Good glucose sensing performance of Co(OH)₂micro-nano sheet arrays is attributed to its unique three-dimensional array structure which guarantees the sufficient diffusion of electrolyte and effective contact between glucose molecule and active sites. Further, the obtained hierarchical Co(OH)₂electrode possesses good selectivity, stability, repeatability and practical detection ability.

This study presents the development of a frequency-controlled drug delivery platform employing gold (Au)-melittin (Mel) conjugates loaded onto titanium dioxide nanocylinders (TiO_₂NCs) decorated with magnetic (M) nanoparticles (NPs). TiO_₂NCs were synthesized via a multi-step anodization and sonication process, providing a high surface-area scaffold for drug loading, while MNPs enabled magnetically-responsive behavior. AuNPs were functionalized with Mel, a potent antimicrobial and anticancer peptide, to enhance its stability and minimize cytotoxicity. The resulting Au-Mel-loaded MNP-TiO_₂NCs exhibited controlled drug release in response to alternating magnetic fields, with peak release occurring within 10 min under stimulation frequencies ranging from 10 Hz to 10 000 Hz. FTIR, TEM, EDX, and zeta potential analyses confirmed successful conjugation and integration of all components.In vitroantibacterial assays demonstrated effective inhibition ofE. coliby magnetically released Au-Mel, while cytotoxicity tests indicated selective activity against HepG2 liver cancer cells with minimal impact on HEK293 cells. This nanoplatform offers a promising solution for dual antibacterial and anticancer therapy with spatiotemporal control via external magnetic fields.

Tellurium (Te) has recently gained attention due to its unique one-dimensional helical chain crystal structure and promising optoelectronic and thermoelectric properties. In this study, we investigate the influence of substrate temperature (296 K-326 K) on the structural and electrical characteristics of ∼20 nm Te films deposited via vacuum thermal evaporation on Si/SiO_₂substrates. Morphological analysis using atomic force microscopy and high-resolution transmission electron microscopy revealed correlation between the substrate temperature and the changes in the structure from trapezoidal to elongated stick-like features. X-ray diffraction and Raman spectroscopy demonstrated that the Te chains were predominantly oriented parallel to the substrate surface atT_S= 326 K. The chain length and packing density were dependent onT_S. Spatially resolved current-voltage measurements show a strong temperature-dependent decrease of the in-plane charge transport, whereas higher-temperature films were characterized by an increased lateral resistance. Scanning Kelvin probe microscopy measurements further reveal surface potential differences of ∼0.6 V between samples. These results demonstrate that small variations in substrate temperature can significantly modulate nanoscale morphology and electrical transport, providing a route to engineer Te-based thin-film devices with tailored performance.

Amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) are promising for nanoscale logic and memory devices, including vertical-channel and monolithic 3D DRAM, owing to their high mobility, uniformity, and compatibility with low-temperature processing. However, nanolithographic definition of a-IGZO channels remains difficult because of their sensitivity to plasma damage and the poor volatility of In, Ga, and Zn etch by-products. Here, we present a scalable self-aligned fabrication strategy that exploits the shadowing effect of angled deposition to realize nanoscale devices without utilizing nanolithography. Using this method, we examined top-gate-top-contact device (TGTC), the widely adopted baseline that suffers from plasma-induced damage and top-gate-bottom-contact device (TGBC), which mitigate channel plasma exposure but undergo severe contact oxidation during post-deposition annealing. To overcome these limitations, we developed a nanoscale vertical TFT architecture in which obliquely deposited Ni/Au electrodes directly form self-aligned source/drain contacts without hard masks or dry etching. The resulting devices had a channel length of 55 nm, achieved an on-current of 2.6 × 10^-6Aµm^-1at a drain bias (V_D) of 40 mV, approximately four times higher than the TGTC and forty times higher than the TGBC which both had similar channel dimensions. AtV_D= 400 mV, a lateral field of 667 kV cm^-1, the on-current further increased to 1.6 × 10^-5Aµm^-1with the off-state current remaining in the 10^-13Aµm^-1range, giving an on/off ratio of 10⁸. These results demonstrate that angled deposition provides both a nanolithography-free route to nanoscale patterning and a device architecture for integrating a-IGZO transistors into future nanoscale logic and memory technologies.

Environmental issues have emerged as a pivotal challenge in the realm of industrial development, rendering the prioritization of renewable energy and sustainable development imperative. Photocatalytic materials should align with these goals by being recyclable and reusable. In this work, spherical nano-Bi₂₄Fe₂O₃₉ was synthesized via a sol-gel method combined with calcination and loaded onto In₂S₃ to construct an S-scheme In₂S₃/Bi₂₄Fe₂O₃₉ heterojunction with superior photocatalytic degradation performance. The composite exhibited an extended light absorption range from 585 nm to 650 nm (IB-30), a narrowed apparent bandgap compared to pure In₂S₃, and significantly improved carrier separation and transfer efficiency. Under the optimal conditions of pH = 7, catalyst dosage = 10 mg, and tetracycline (TC) concentration = 10 mg l^-1, the IB-30 material achieved a removal rate of 85.8% for tetracycline, which is 1.7 times and 2.46 times higher than that of pure In₂S₃ and pure Bi₂₄Fe₂O₃₉, respectively. Driven by the built-in electric field, photogenerated electrons follow an S-scheme pathway for transfer, while・O₂^-(superoxide anion radicals) and h⁺(holes) serve as the primary active species, effectively facilitating the photocatalytic degradation reaction. This study provides new insights into developing efficient and stable visible-light-driven photocatalysts.

Lithium sulfur batteries (LSBs) are regarded as the potential next-generation energy storage system due to their high theoretical energy density and low cost. However, LSBs also face problems such as the dissolution of lithium polysulfide, volume expansion, and the formation of lithium dendrites. Optimizing the design of sulfur cathode materials to tackle these issues at their source is the primary approach to enhancing the performance of LSBs, since the inherent limitations of sulfur are the root cause of the challenges in LSBs. The review covers the latest research on carbon-based sulfur cathode materials of LSBs, including structural design and functional optimization strategies, aiming to prepare multifunctional carbon-based sulfur cathodes by integrating physical confinement, chemical adsorption, and catalytic effect towards lithium polysulfides. The future development directions are prospected, including material design, optimization of reaction mechanisms, and low-cost preparation technologies.

This study investigates the quantum efficiency (QE) and operational lifetime of a negative electron affinity GaAs truncated nanocone array (TNCA) photocathode benchmarked against a conventional flat GaAs photocathode under varying activation temperatures. The TNCA structure demonstrated a QE of up to 13.6% at 590 nm with room temperature (RT) activation-approximately 1.5 times higher than its flat counterpart. This enhancement is due to Mie resonance effects within the nanostructure, as confirmed by finite-difference time-domain simulations. Moreover, the TNCA photocathode exhibits significantly extended charge lifetime, with enhancement factors of ∼6.1 and ∼19.8 under RT and 50 °C activations, respectively. These gains are primarily attributed to increased effective surface area and optimized dipole layer formation at elevated temperatures. In addition, shorter excitation wavelengths further contribute to lifetime improvements. These findings underscore the TNCA GaAs photocathode's potential as a high QE, long lifetime electron source for many large-scale electron accelerators.

In this paper, we present results of x-ray diffraction investigations of GaN micro-pillars grown on GaN template. These rods are special in so far that they have stable a- and m-plane side walls and dodecagonal and not hexagonal shape as usual. Such growth mode is simulated by adding As as surfactant. The work shows the influence of changing the amount of gallium and arsenic and lowering the temperature on the growth of micro-pillars. Changing the growth parameters led to both a change in the density of the growing micro-pillars, their height and width, and their structural parameters, such as a disturbance in the direction of growth of the structures. In order to characterize the studied samples, measurements were carried on the configuration from the surface and from the edge of the sample. This measurements method allowed to visualize the structure in the perpendicular and parallel directions of the micro-pillars growth. In addition, the strain and mosaic analysis showed correlations between the resulting shape and density of the rods and the strain of the GaN-pillar and GaNAs crystalline lattice.

This paper investigates the influence of different abrasive morphology of silicon carbide (SiC) through molecular dynamics simulations on the scratching process, aiming to provide theoretical guidance and process optimization directions for the precision machining of SiC materials. The paper analyzes the differences in contact area, stress distribution, and material deformation mechanisms between sphere, cone, frustum cone, face of a square pyramid and edge of a square pyramid abrasives during the scratching process. It focuses on key characteristics such as scratching force, atom removal, surface topography, amorphous deformation, and subsurface stress distribution. The results show that the morphology of the abrasive significantly affects machining efficiency and surface quality, with sphere abrasives being more prone to plastic deformation and pyramid abrasives tending to cause brittle fracture. Additionally, the interaction between abrasive morphology and SiC crystal orientation also has a significant impact on the scratching process. This paper not only reveals the surface formation mechanisms of SiC under different abrasive morphology but also provides important theoretical and experimental basis for achieving more efficient and precise SiC material machining.