Nanotechnology最新文献

In recent years, significant advancements in nanotechnology have improved the various disciplines of scientific fields. Nanomaterials, like, carbon-based (carbon nanotubes, graphene), metallic, metal oxides, conductive polymers, and 2D materials (MXenes) exhibit exceptional electrical conductivity, mechanical strength, flexibility, thermal property and chemical stability. These materials hold significant capability in transforming material science and biomedical engineering by enabling the creation of more efficient, miniaturized, and versatile devices. The indulgence of nanotechnology with conductive materials in biological fields promises a transformative innovation across various industries, from bioelectronics to environmental regulations. The conductivity of nanomaterials with a suitable size and shape exhibits unique characteristics, which provides a platform for realization in bioelectronics as biosensors, tissue engineering, wound healing, and drug delivery systems. It can be explored for state-of-the-art cardiac, skeletal, nerve, and bone scaffold fabrication while highlighting their proof-of-concept in the development of biosensing probes and medical imaging. This review paper highlights the significance and application of the conductive nanomaterials associated with conductivity and their contribution towards a new perspective in improving the healthcare system globally.

This study examines the exciton dynamics in InGaN/GaN core-shell nanorods using time-resolved cathodoluminescence (TRCL), which provides nanometer-scale lateral spatial and tens of picoseconds temporal resolutions. The focus is on thick (>20 nm) InGaN layers on the non-polar, semi-polar and polar InGaN facets, which are accessible for study due to the unique nanorod geometry. Spectrally integrated TRCL decay transients reveal distinct recombination behaviours across these facets, indicating varied exciton lifetimes. By extracting fast and slow lifetime components and observing their temperature trends along with those of the integrated and peak intensity, the differences in behaviour were linked to variations in point defect density and the degree and density of localisation centres in the different regions. Further analysis shows that the non-polar and polar regions demonstrate increasing lifetimes with decreasing emission energy, attributed to an increase in the depth of localisation. This investigation provides insights into the intricate exciton dynamics in InGaN/GaN nanorods, offering valuable information for the design and development of optoelectronic devices.

In this work we present self-organized regular patterns in a solution system through uphill-diffusion. Micrometer thick organic semiconductor solution is sandwiched between a substrate and cover-plate. Self-assembled regular patterns can be observed on the substrate after solvent evaporation. Different micro-patterns and pattern defects were displayed and analyzed. Mechanisms of defect formation, mode selection process during patten generation, and pattern sedimentation onto substrate from solution were proposed. Organic thin film transistors were fabricated with the assembled line patterns which demonstrate a promising way to produce patterned micro/nano materials.

CoFe and NiFe are used in the construction of Si-based metal-semiconductor-type photodiodes. Thin film layers are sputtered onto thep-Si surface where Al metal contacts are deposited using the thermal evaporation technique. Film characteristics of the layers are investigated with respect to the crystalline structure and surface morphology. Their electrical and optical properties are investigated using dark and illuminated current-voltage measurements. When these two diodes are compared, Al/NiFe/p-Si exhibits better rectification properties than Al/CoFe/p-Si diode. There is also a high barrier height where these values for both diodes increase with illumination. According to the current-voltage analysis, the existence of an interlayer causes a deviation in diode ideality. In addition, the response to bias voltage, the derivation of electrical parameters, and the light sensitivity of diodes are evaluated using current-voltage measurements under different illumination intensities and also transient photosensitive characteristics.

Al-doped Ga₂O₃microbelts with widths ranging from 20 to 154μm and lengths up to 2 mm were grown using carbothermal reduction. Based on these ultra-wide microbelts, single-microbelt (37μm wide) and double-microbelts(38μm/42μm wide) metal-semiconductor-metal photoconductive ultraviolet (UV) detectors PDs were fabricated and their optoelectronic performances were investigated at Vacuum-UV (VUV) wavelengths of 185 nm. Under irradiation of 185 nm, the Al-doped Ga₂O₃PD has a very-high photocurrent (I_ph) of 192.07μA and extremely low dark current (I_d) of 156 fA at 10 V, and presents a ultra-high light-to-dark current ratio of 1.23 × 10⁹. The responsivity (R), external quantum efficiency (EQE), and detectivity (D*) of the double-microbelts detector device were 1920 A W^-1, 9.36 × 10⁵%, and 8.6 × 10¹⁶Jones, respectively. Since the bandgap of the Al-doped microbelts becomes wider, and the fabricated detector has weaker sensitivity to radiation in the 254/365 nm wavelengths. Compared with the 254 nm and 365 nm UV cases, the devices under 185 nm VUV show the excellent high selectivity ratios of 1.47 × 10⁶and 1.7× 10⁷, respectively. This paper should provide a new insight on the VUV photodetectors utilizing Ga₂O₃microbelts.

Reduced graphene oxide (rGO) has unique physicochemical properties that make it suitable for therapeutic applications in neurodegenerative scenarios. This study investigates the therapeutic potential of rGO in a cuprizone-induced demyelination model in mice through histomorphological techniques and analysis of biochemical parameters. We demonstrate that daily intraperitoneal administration of rGO (1 mg ml^-1) for 21 days tends to reduce demyelination in theCorpus callosumby decreasing glial cell recruitment during the repair mechanism. Additionally, rGO interferes with oxidative stress markers in the brain and liver indicating potential neuroprotective effects in the central nervous system. No significant damage to vital organs was observed, suggesting that multiple doses could be used safely. However, further long-term investigations are needed to understand rGO distribution, metabolism, routes of action and associated challenges in central neurodegenerative therapies. Overall, these findings contribute to the comprehension of rGO effectsin vivo, paving the way for possible future clinical research.

The rising environmental awareness has spurred the extensive use of green materials in electronic applications, with bio-organic materials emerging as attractive alternatives to inorganic and organic materials due to their natural biocompatibility, biodegradability, and eco-friendliness. This study showcases the natural rubber based resistive switching memory devices and how varying sulphur concentrations (0 - 0.8 wt.%) in natural rubber thin films impact the resistive switching characteristics. The natural rubber was formulated and processed into a thin film deposited on an ITO substrate as the bottom electrode and with an Ag film as the top electrode. The addition of sulphur modifies the degree of crosslinking in the natural rubber thin film, from which the concentration of -C=C- group and density of defect site (S+) are affected, and hence the resistive switching behavior of the memory device. The devices exhibit bipolar resistance with symmetric switching characteristics which are attributed to the formation of conductive paths facilitate by electron transport along -C=C- and S+ defect sites between the two electrodes. Notably, a sample with 0.2 wt.% sulphur exhibits a high ON/OFF ratio (104), a large memory window (5.5 V), prolonged data retention (10 years), and reliable endurance (120 cycles). These findings highlight the potential of natural rubber as a promising material for eco-friendly resistive-switching random access memory applications. .

Three-dimensional (3D) free-standing nanostructures based on electron-beam lithography (EBL) have potential applications in many fields with extremely high patterning resolution and design flexibility with direct writing. In numerous EBL processes designed for the creation of 3D structures, the multilayer resist system is pivotal due to its adaptability in design. Nevertheless, the compatibility of solvents between different layers of resists often restricts the variety of feasible multilayer combinations. This paper introduces an innovative approach to address the bottleneck issue by presenting a novel concept of multilayer resist dry stacking, which is facilitated by a near-zero adhesion strategy. The poly(methyl methacrylate) (PMMA) film is stacked onto the hydrogen silsesquioxane (HSQ) resist using a dry peel and release technique, effectively circumventing the issue of HSQ solubilization by PMMA solvents typically encountered during conventional spin-coating procedures. Simultaneously, a dry lift-off technique can be implemented by eschewing the use of organic solvents during the wet process. This pioneering method enables the fabrication of high-resolution 3D free-standing plasmonic nanostructures and intricate 3D free-standing nanostructures. Finally, this study presents a compelling proof of concept, showcasing the integration of 3D free-standing nanostructures, fabricated via the described technique, into the realm of Fabry-Perot cavity resonators, thereby highlighting their potential for practical applications. This approach is a promising candidate for arbitrary 3D free-standing nanostructure fabrication, which has potential applications in nanoplasmonics, nanoelectronics, and nanophotonics.

Nanoparticle-based antigen carrier systems have become a significant area of research with the advancement of nanotechnology. Biodegradable polymers have emerged as particularly promising carrier vehicles due to their ability to address the limitations of existing vaccine systems. In this study, we successfully encapsulated the G5-24 linear peptide, located between amino acids 253 and 275 in the primary sequence of the rabies virus G protein, into biodegradable and biocompatible PLGA copolymer using the double emulsion solvent evaporation method. The resulting nanoparticles had a size of approximately 230.9 ± 0.9074 nm, with a PDI value of 0.168 ± 0.017 and a zeta potential value of -9.86 ± 0.132 mV. SEM images confirmed that the synthesized nanoparticles were uniform in size and distribution. Additionally, FTIR spectra indicated successful peptide loading into the nanoparticles. The encapsulation efficiency of the peptide-loaded nanoparticles was 73.3%, with a peptide loading capacity of 48.2% and a reaction yield of 30.4%. Peptide release studies demonstrated that 65.55% of the peptide was released in a controlled manner over 28 d, following a 'biphasic burst release' profile consistent with the degradation profile of PLGA. This controlled release is particularly beneficial for vaccine studies. Cytotoxicity tests revealed that the R-NP formulation did not induce cytotoxicity in fibroblast cells and enhanced NO production in macrophages, indicating its potential for vaccine development.

Liquid-aluminum tends to adhere to some surfaces rather than others, and the underlying mechanism of the differences in adhesion of liquid-aluminum on different surfaces is still unclear. This manuscript takes liquid-aluminum/aluminum and liquid-aluminum/silicon interfaces as research objects, revealing that solid aluminum surface is aluminophilic but the solid silicon surface is aluminophobic, mainly due to differences in interfacial thermal conductance (ITC) between two interfaces. We also investigate effect of surface temperature on adhesion characteristics of liquid-aluminum on aluminum/silicon surfaces, and decode the reasons from lattice integrity and phonon spectra. It is shown that vibrational state with intact lattice excites fewer low frequency phonons with increasing surface temperature, resulting in a decrease in ITC and thus adhesion force. In diffusion state where lattice is fractured resulting from high temperature, interfacial adhesion is increased due to surface defects.