Nanotechnology

X-ray methods can offer unique insights into the structural and electronic properties of nanomaterials. Recent years have seen a dramatic improvement in both x-ray sources and x-ray optics, providing unprecedented resolution and sensitivity. These developments are particularly useful for nanowires, which are inherently small and give weak signals. This review gives an overview of how different x-ray methods have been used to analyze nanowires, showing the different types of insight that can be gained. The methods that are discussed include x-ray diffraction, x-ray fluorescence, x-ray photoelectron spectroscopy and x-ray photoelectron emission microscopy, as well as several others. The review is especially focused on high spatial resolution methods used at the single nanowire level, but it also covers ensemble experiments.

With advancements in thin-film deposition, nanofabrication, and material characterization techniques, quantum devices leveraging nanoscale quantum phenomena have emerged across various fields, including quantum computing, sensing, communication, and metrology. Among these, quantum sensing harnesses the unique properties of quantum systems to achieve highly sensitive and precise measurements of physical quantities such as magnetic and electric fields, temperature, pressure, and even biological events. In this perspective, we highlight some popular magnetic quantum sensors used for magnetic sensing and imaging, and emerging spintronic quantum sensors that exploit the quantum mechanical properties of electron spin for similar applications. Most of the techniques discussed remain in lab-based stages, with limited preliminary data reported. However, the authors believe that, with continued progress in spintronics, these nano- and micro-scale spintronic devices—offering superior and unique magnetic quantum properties—could open new horizons in biomedical applications, including single-cell and single-molecule detection, large-scale protein profiling, sub-micrometer resolution medical imaging, and beyond.

Metallic nanoparticles with different physical properties have been screen printed as authentication tags on different types of paper. Gold and silver nanoparticles show unique optical signatures, including sharp emission bandwidths and long lifetimes of the printed label, even under accelerated weathering conditions. Magnetic nanoparticles show distinct physical signals that depend on the size of the nanoparticle itself. They were also screen printed on different substrates and their magnetic signals read out using a magnetic pattern recognition sensor and a vibrating sample magnetometer. The novelty of our work lies in the demonstration that the combination of nanomaterials with optical and magnetic properties on the same printed support is possible, and the resulting combined signals can be used to obtain a user-configurable label, providing a high degree of security in anti-counterfeiting applications using simple commercially-available sensors.

Nanoparticles and nanomaterials are revolutionizing medicine by offering diverse tools for diagnosis and therapy, including devices, contrast agents, drug delivery systems, adjuvants, therapeutics, and theragnostic agents. Realizing full applied potential requires a deep understanding of the interactions of nano dimensional objects with biological cells. In this study, we investigate interaction of single-crystal diamond nanoneedles (SCDNNs) containing silicon vacancy (SiV^-) color centers with biological substances. Four batches of the diamond needles with sizes ranging between 200 nm and 1300 nm and their water suspensions were used in these studies. The human lung fibroblast cells were used for the proof-of-concept demonstration. Employing micro-photoluminescence (PL) mapping, confocal microscopy, and lactate dehydrogenase (LDH) viability tests, we evaluated the cellular response to the SCDNNs. Intriguingly, our investigation with PL spectroscopy revealed that the cells and SCDNNs can coexist together with approved efficient registration of SiV^- centers presence. Notably, LDH release remained minimal in cells exposed to optimally sized SCDNNs, suggesting a small number of lysed cells, and indicating non-cytotoxicity in concentrations of 2–32 µg ml⁻¹. The evidence obtained highlights the potential of SCDNNs for extra- or/and intracellular drug delivery when the surface of the needle is modified. In addition, fluorescent defects in the SCDNNs can be used for bioimaging as well as optical and quantum sensing.

Resistive random access memory (RRAM) is considered an attractive candidate for next generation memory devices due to its competitive scalability, low-power operation and high switching speed. The technology however, still faces several challenges that overall prohibit its industrial translation, such as low yields, large switching variability and ultimately hard breakdown due to long-term operation or high-voltage biasing. The latter issue is of particular interest, because it ultimately leads to device failure. In this work, we have investigated the physicochemical changes that occur within RRAM devices as a consequence of soft and hard breakdown by combining full-field transmission x-ray microscopy with soft x-ray spectroscopic analysis performed on lamella samples. The high lateral resolution of this technique (down to 25 nm) allows the investigation of localized nanometric areas underneath permanent damage of the metal top electrode. Results show that devices after hard breakdown present discontinuity in the active layer, Pt inclusions and the formation of crystalline phases such as rutile, which indicates that the temperature increased locally up to 1000 K.

c-Si/a-Si:H-based solar cells are characterized by impressive efficiencies for silicon based devices. In this paper, we present a comprehensive atomistic simulation study of the structural and transport properties of crystalline silicon and hydrogenated amorphous silicon heterostructures for photovoltaic applications. By leveraging state-of-the-art molecular dynamics simulations with a machine-learned force field, we explore the effects of thermal boundary resistance as well as hydrogen diffusion on device performance. The simulations reveal the dependence of thermal properties on crystalline orientations, cooling rates of the amorphous layer, and interface morphology. A systematic investigation of hydrogen diffusion demonstrates its impact on heat transport and structural stability, highlighting the role of moderate hydrogenation ($\unicode{x2A7D}\kern-3.3pt10\%$) and specific orientations in enhancing thermal dissipation and reducing degradation. These findings provide atomistic insights into optimizing c-Si/a-Si:H interfaces, enabling improved thermal management and long-term stability for high-performance solar cells.

Given the promising applications of large magnetoresistance in the Dirac semimetal cadmium arsenide (Cd₃As₂), extensive research into Si-compatible Cd₃As₂ devices is highly desirable. To prevent surface degradation and oxidation, the implementation of a protection layer on Cd₃As₂ is imperative. In this study, two vastly different protecting layers were prepared on top of two Cd₃As₂ samples. A zinc telluride layer was grown on top of one Cd₃As₂ film, giving rise to a ten-fold increased mobility, compared to that of the pristine Cd₃As₂ sample. Interestingly, unusual negative magnetoresistance is observed in the hexagonal boron nitride-capped Cd₃As₂ device when a magnetic field is applied perpendicularly to the Cd₃As₂ plane. This is in sharp contrast to the chiral anomaly that requires a magnetic field parallel to the Cd₃As₂ plane. We suggest that a protection layer on molecular beam epitaxy-grown Cd₃As₂ should be useful for realising its great device applications in magnetic sensing.

Over the past decade, graphene quantum dots (GQDs) have gained an inexhaustible deal of attention due to their unique zero-dimensional (0D) and quantum confinement properties, which boosted their wide research implication and reliable applications. As one of the promising 0D member and rising star of the carbon family, plant leaf-derived GQDs have attracted significant attention from scholars working in different research fields. Owing to its novel photophysical properties including high photo-stability, plant leaf-derived GQDs have been increasingly utilized in the fabrication of optoelectronic devices. Their superior biocompatibility finds their use in biotechnology applications, while their fascinating spin and magnetic properties have maximized their utilization in spin-manipulation devices. In order to promote the applications of plant leaf-derived GQDs in different fields, several studies over the past decade have successfully utilized plant leaf as sustainable precursor and synthesized GQDs with various sizes using different chemical and physical methods. In this review, we summarize the Neem and Fenugreek leaves based methods of synthesis of plant leaf-derived GQDs, discussing their surface characteristics and photophysical properties. We highlight the size and wavelength dependent photoluminescence properties of plant leaf-derived GQDs towards their applications in optoelectronic devices such as white light-emitting diodes and photodetectors, as well as biotechnology applications such as in vivo imaging of apoptotic cells and spin related devices as magnetic storage medium. Finally, we particularly discuss possible ways of fine tuning the spin properties of plant leaf-derived GQD clusters by incorporation with superconducting quantum interference device, followed by utilization of atomic force microscopy and magnetic force microscopy measurements for the construction of future spin-based magnetic storage media and spin manipulation quantum devices so as to provide an outlook on the future spin applications of plant leaf-derived GQDs.

The excellent collection ability of the photo-generated holes from the poly-crystalline lead trihalide perovskite thin films to the poly[3-(4-carboxybutyl)thiophene-2,5,-diyl] (P3CT) or poly(3-hexylthiophene) (P3HT) polymer layer has been used to realize the highly efficient solar cells. The electronic and molecular structures of the p-type polymers play the decisive roles in the photovoltaic responses of the resultant perovskite solar cells. It is fundamental to understand the relation between the material properties and the photovoltaic performance in order to achieve the highest power conversion efficiency. We review the molecular packing, morphological, optical, excitonic, and surface properties of the P3CT and P3HT polymer layers in order to correctly understand the working mechanisms of the resultant solar cells, thereby predicting the required material properties of the used p-type polymers as the efficient hole transport layer.

Magnetic domain walls and skyrmions in thin film micro- and nanostructures have been of interest to a growing number of researchers since the turn of the millennium, motivated by the rich interplay of materials, interface and spin physics as well as by the potential for applications in data storage, sensing and computing. This review focuses on the manipulation of magnetic domain walls and skyrmions by piezoelectric strain, which has received increasing attention recently. Static strain profiles generated, for example, by voltage applied to a piezoelectric-ferromagnetic heterostructure, and dynamic strain profiles produced by surface acoustic waves, are reviewed here. As demonstrated by the success of magnetic random access memory, thin magnetic films have been successfully incorporated into complementary metal-oxide-semiconductor back-end of line device fabrication. The purpose of this review is therefore not only to highlight promising piezoelectric and magnetic materials and their properties when combined, but also to galvanise interest in the spin textures in these heterostructures for a variety of spin- and straintronic devices.

Metasurfaces (MSs), two-dimensional arrays of engineered nanostructures, have revolutionized optics by enabling precise manipulation of electromagnetic waves at subwavelength scales. These platforms offer unparalleled control over amplitude, phase, and polarization, unlocking advanced applications in imaging, communication, and sensing. Among them, plasmonic MSs stand out for their ability to exploit surface plasmon resonances (SPRs)—collective electron oscillations at metal-dielectric interfaces. This phenomenon enables extreme light confinement and field enhancement, leading to highly efficient light-matter interactions. The remarkable sensitivity of SPR to refractive index variations makes plasmonic MSs ideal for detecting minute biochemical and environmental changes with exceptional precision. Additionally, their tunable SPR characteristics enhance multifunctionality, enabling adaptive and real-time sensing. By leveraging these advantages, plasmonic MSs address critical challenges in modern sensing, driving breakthroughs in biomedical diagnostics, environmental monitoring, and chemical detection. This perspective explores recent advancements in plasmonic MSs, emphasizing flexible, multifunctional designs and the transformative role of artificial intelligence in optimizing performance and enabling real-time data analysis.

The optical response manipulation of two-dimensional materials is crucial for designing and optimizing high-performance optoelectronic devices. Previously, optical modulation in two-dimensional semiconductors primarily relied on adjusting carrier density through optical excitation or charge injection using the energy band-filling effect. Recently, twist angle has been found to tune the optical and optoelectronic properties of van der Waals structure, but its impact on the transient optical response remains unexplored. Herein, we demonstrate that twist angle can effectively regulate carrier behaviors by tracing the evolution of optical responses in twisted bilayer WS₂ from 0° to 60°. Both Raman and PL spectra consistently show that the optical responses of WS₂ bilayers are highly dependent on the twist angle. Exciton behavior and phonon modes exhibit similarity at twist angles near 0° and 60°, but significantly change as the angle approaches 30°. Moreover, the impact of the twist angle on the transient optical responses was carefully investigated using a femtosecond pump-probe technique. The results reveal a significant decrease in carrier thermalization/relaxation time and exciton formation/recombination time at the WS₂ bilayers with twist angle of ∼31.0°, as compared to twist angles of ∼2.9° and ∼58.9°, which can be attributed to the accumulation of intralayer carriers due to weakened interlayer coupling. These results demonstrate that twist angle can effectively modulate the optical response of twisted 2D materials. Our study elucidates the dynamic carrier behavior in twisted bilayer WS₂ and provides new insights for designing future optoelectronic and photonic devices.

Two-dimensional (2D) semiconductors have received a lot of attention as the channel material for the next generation of transistors and electronic devices. On the other hand, insulating 2D gate dielectrics, as possible materials for gate dielectrics in transistors, have received little attention. We performed an experimental study on bismuth oxychloride, which is theoretically proposed to have good dielectric properties. High-quality bismuth oxychloride single crystals have been synthesized, and their high single crystallinity and spatial homogeneity have been thoroughly evidenced by x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, transmission electron microscopy (TEM), and scanning TEM studies. We then mechanically exfoliated high-quality BiOCl crystals to fabricate metal–insulator–metal (MIM) capacitors and measured the dielectric properties at various frequencies and different thicknesses. We found that BiOCl exhibits an out-of-plane static dielectric constant up to 11.6, which is 3 times higher than 2D hexagonal boron nitride making it a suitable candidate for 2D dielectrics. We also carried out cross-section TEM studies to look into the MIM interface and provide some future directions for their integration with metal-dielectric interfaces and possibly with other 2D devices.

Polymethylmethacrylate (PMMA) is commonly used as a support material in graphene transfer. Heat treatment exceeding 250 °C is required to remove the PMMA after the transfer process. However, the transparent flexible substrates conventionally used for graphene transfer generally exhibit low heat resistance. This hinders the complete removal of the PMMA, resulting in low electrical conductivity of graphene. Therefore, we focused on developing heat-resistant transparent polyimide (TPI) films as substrates for graphene transfer. The interactions between the TPI substrates and chemical vapor deposition graphene were systematically investigated. The effects of the TPI surface roughness, chemical composition, and chemical structure of the TPI, and doping effects of the substrate were examined, and a silane coupling agent (SCA) was coated to bring the TPI surface properties closer to those of a quartz glass substrate. Three-layer stacked graphene (3LG) on TPI, in which the –CF₃ group in TPI is replaced with –CH₃, exhibited the highest carrier mobility of 3610 cm² Vs⁻¹ at a constant carrier density after annealing. The sheet resistance of the 3LG on TPI annealed after vapor phase deposition of the SCA was lower than that of the standard TPI and decreased to 82 Ω/sq. after doping with bis(trifluoromethanesulphonyl)amide. This is comparable to the electrical properties of graphene on a quartz glass substrate. Furthermore, after doping, the 3LG/TPI maintained a high optical transmittance of 88.8% at a wavelength of 550 nm. The knowledge obtained from this study will allow graphene flexible transparent conductive films to be transferred onto TPI for use in transparent heaters and solar cells as well as to control the electrical properties for various device applications by modifying the roughness, chemical structure, and coating layers on the surface of the TPI substrate.

Silicon dioxide nanoparticles (SiO₂ NPs) are widely used to manufacture products for human consumption. However, their large-scale use in many fields poses risks to industrial workers. In this study, we investigated the cytotoxic and inflammatory potential of SiO₂ NPs in the human cell line A549, representing the human alveolar epithelium. The NPs were characterized using energy-dispersive x-ray spectroscopy coupled with scanning electron microscopy, x-ray diffraction, transmission electron microscopy, dispersion, and dynamic light scattering. The effects on A549 cells were monitored by cell adhesion and proliferation using electrical impedance, as well as cell viability, apoptosis, necrosis, and secretion of multiple inflammatory mediators. SiO₂ NPs did not alter the adhesion and proliferation of A549 cells but led to cell death by apoptosis at the highest concentrations tested. SiO₂ NP impacted the secretion of pro-inflammatory (tumor necrosis factor-α, interleukin (IL)-8, monocyte chemoattractant protein-1, eotaxin, regulated upon activation, normal T cell expressed and secreted, vascular growth factor, granulocyte–macrophage colony-stimulating factor, and granulocyte-colony stimulating factor) and anti-inflammatory (IL-1ra and IL-10) mediators. These results indicate that, even with little impact on cell viability, SiO₂ NPs can represent a silent danger, owing to their influence on inflammatory mediator secretion and unbalanced local homeostasis.

Friction and wear are critical aspects that significantly impact the efficiency and durability of mechanical systems. The demand for improved lubricating oils capable of reducing friction and wear has spurred the exploration of advanced additives. Two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides (MXene), a new class of materials, have emerged as promising additives with exceptional tribological properties. This review paper aims to understand the usability of MXene, specifically the ones derived from Ti₃C₂T_X as anti-friction and antiwear additives in lubricating oils. An elaborate discussion is presented about the synthesis and characterization techniques employed in the synthesis of Ti₃C₂T_X (MXene), emphasizing their unique structural and surface properties that could contribute to their tribological performance, followed by their influence on the lubricant's tribological properties is thoroughly discussed. The underlying anti-friction and anti-wear mechanisms, their ability to form tribofilms on sliding surfaces, reduce direct metal-to-metal contact, and minimize wear are also highlighted. Additionally, the role of MXene in modifying the lubricant's chemical and physical interactions with sliding surfaces is analyzed. This review also attempts to identify and address the roadblocks hindering the use of Ti₃C₂T_X MXene in lubricating oils, such as their aggregation tendencies, stability under extreme conditions, and potential side effects on lubricant properties along with the tentative strategies to overcome these hurdles. Relevant experimental findings in which Ti₃C₂T_X derived 2D nano-sheets have been explored as friction and wear-reducing additives in different lubricating oils are critically assessed. Although these MXene are claimed to be highly effective as lubricant additives in lubricating oils owing to their unique properties and versatile chemistry, further research is urgently needed to address the challenges and optimize the formulation and integration of MXene into lubricating oils for practical implementation. This article comprehensively discusses Ti₃C₂T_X MXene as friction and wear-reducing additives in lubricating oils, highlighting the pressing need for further research and the potential for future developments in this field.

In light of the industry's environmental constraints, sustainable manufacturing technology has emerged as a critical goal for emerging applications. Due to the increased need for electronic production around the world, the requirement for environmentally safe technology is the necessity of this decade as the world government shifts towards sustainability in all manufacturing technology. Henceforth, printed electronics will be one such solution to regulate the electronic device and components production requirement of this decade. The article has discussed about the recent advances in inkjet-printed electronics across a wide range of electronics applications. We have discussed several inkjet printing inks and their formulation methods, which are required for minimizing environmental waste. In addition, we have discussed the future scope of printed electronics production and its impact on the economy as well as the environment.

Hydrogen is regarded as an ideal substitute for fossil fuels on account of its advantages of high energy density, zero carbon emissions, and abundant reserves. Solid-state hydrogen storage is one of the most promising hydrogen storage methods in terms of high-volume storage density and safety. MgH₂ is a promising solid hydrogen storage material because of its high hydrogen storage capacity and favorable cycle reversibility. Nevertheless, its inferior thermodynamic and kinetic properties restrict its extensive application. Catalyst modification is considered to be an efficient way to enhance the thermodynamic and kinetic properties of hydrogenation and dehydrogenation for MgH₂. This review summarizes the latest research progress on MXene-based composites, such as MAX, single metal MXene, bimetallic MXene, MXene/elemental metal, and MXene/transition metal compounds for promoting the hydrogen storage performances of MgH₂. At the same time, the catalyst of MXene-based composites to optimize the hydrogenation/dehydrogenation kinetics, long cycle performance and catalytic mechanism of Mg/MgH₂ are discussed in detail.

Radiation detectors have gained significant attention due to their extensive applications in high-energy physics, medical diagnostics, aerospace, and nuclear radiation protection. Advances in relevant technologies have made the drawbacks of traditional semiconductor detectors, including high leakage currents and instability, increasingly apparent. Ga₂O₃, diamond, and BN represent a new generation of semiconductor materials following GaN and SiC, offering wide bandgaps of around 5 eV. These ultra-wide bandgap semiconductors demonstrate excellent properties, including ultra-low dark current, high breakdown fields, and superior radiation tolerance, underscoring their promising potential in radiation detection. In this review, we first discuss the materials and electrical properties of Ga₂O₃, diamond, and BN, along with the general performance metrics relevant to radiation detectors. Subsequently, the review provides a comprehensive overview of the research progress in x-ray detection, charged particle detection (e.g. α particles and carbon ions), as well as fast neutron and thermal neutron detection, focusing on aspects such as chip fabrication processes, device architectures, and testing results for radiation detectors based on these three materials.

X-ray methods can offer unique insights into the structural and electronic properties of nanomaterials. Recent years have seen a dramatic improvement in both x-ray sources and x-ray optics, providing unprecedented resolution and sensitivity. These developments are particularly useful for nanowires, which are inherently small and give weak signals. This review gives an overview of how different x-ray methods have been used to analyze nanowires, showing the different types of insight that can be gained. The methods that are discussed include x-ray diffraction, x-ray fluorescence, x-ray photoelectron spectroscopy and x-ray photoelectron emission microscopy, as well as several others. The review is especially focused on high spatial resolution methods used at the single nanowire level, but it also covers ensemble experiments.

Nanowires (NWs) of III-V semiconductors provide a promising platform for the development of electronic and photonic components of integrated circuits. For the development of complex NW-based devices, it is crucial to precisely study structural, electronic, and optical properties at the nanoscale. Scanning tunneling microscopy (STM) is commonly used to achieve such precision. In this work we optimize the tunneling contact parameters in an ultrahigh vacuum STM (at room temperature) for reproducible high-quality topographic imaging of conductive GaP NWs, especially promising for photonic integrated circuits. Two methods were employed for transferring NWs onto auxiliary conducting substrates: ultrasonication in liquid (deionized water or isopropyl alcohol) followed by drop casting and mechanical scratching. Five substrate materials were tested: highly oriented pyrolytic graphite, single crystal silicon wafers, thin films of nickel, indium tin oxide and gold. The experimental results showed that the tunneling contact parameters, substrate material, and transfer method significantly affect the quality of STM images. It was found that bias voltages of 7-10 V, tunneling current up to 400 pA, and image recording rates in the range of 500-1500 nm/s were optimal, with nickel-coated substrates providing the best stability and image quality. Potentially harmful procedures for NW and substrate surfaces, such as ion treatment and high-temperature annealing, were avoided during the sample preparation. The results expand the understanding of STM studies of NWs and their applications in electronic and photonic devices.

Gate-all-around (GAA) nanosheet field-effect transistors (FETs) have significantly advanced nanoscale device technology by mitigating short-channel effects. These GAA structures are becoming essential in sub-3nm technology and are evolving into complementary FETs. Despite the reduction in variability achieved by multi-gate structures, random discrete dopants (RDDs) in source and drain regions continue to pose challenges. This study addresses the local variability induced by RDDs, particularly in the source and drain extensions in GAA nanosheet FETs. Through statistical quantum transport simulations under a ballistic approximation, we investigate parameters such as spacer length, channel width, and channel thickness. The results show that RDDs in the source and drain extensions cause not only threshold voltage variation but also increase resistance and reduce ON-state current. GAA nanosheet FETs with a 3 nm×10 nm cross-sectional channel and 5 nm spacer length exhibit 10% reduction in ON-state current compared to the ideal device, along with a standard deviation (variability) of 0.35 µA. Mitigation of these effects requires the use of thin, wide, and large cross-section nanosheets and short spacer lengths.

Graphene Oxide (GO) is a two-dimensional (2D) nanomaterial largely exploited in many fields. Its preparation, usually performed from graphite in an oxidant environment, generally affords two-dimensional layers with a broad size distribution, with overoxidation easily occurring.
Here, we investigate the formation, along the Hummers synthesis of GO, of carbon nanoparticles isolated from GO and characterized through morphological and spectroscopic techniques. The purification methodology here applied is based on dialysis and results highly advantageous, since it does not involve chemical processes, which may lead to modifications in the composition of GO layers. Using a cross-matched characterization approach among different techniques, such as XPS, cyclic voltammetry and fluorescence spectroscopy, we demonstrate that the isolated carbon nanoparticles are constituted by layers that are highly oxidized at the edges and are stacked due to π-π interaction among their aromatic basal planes and H-bonded via their oxidized groups. These results, while representing a step forward in the comprehension of the structure of long-debated carbon debris in GO, strongly point to the introduction of dialysis as an indispensable step toward the preparation of more controlled and homogeneous GO layers and to its use for the valorization of low molecular weight GO species as luminescent carbon nanoparticles.

In this work, Pd-TiO2/ZnIn2S4 nanowires (Pd-Ti-Nws/ZIS) heterostructures catalysts were prepared and applied to photocatalytic hydrogen evolution under simulated sunlight. The results revealed that the hydrogen production rate of Pd-Ti-Nws-40/ZIS was as high as 66.62 mmol·g-1·h-1, which was 20.5 and 418 times as much as that of pure ZIS and Pd-Ti-Nws, respectively. After 5 cycles, the hydrogen production of the photocatalyst can still reach about 60 mmol within 120 min. According to the results of photochemistry and XPS, Pd-Ti-Nws/ZIS meets the S-scheme heterojunction system, which is beneficial to inhibit the recombination of photogenerated holes and electrons and increase carrier transport rate through the S-scheme heterojunction. Under light radiation, Pd-Ti-Nws is positively charged due to the accumulation of holes, and ZIS is negatively charged due to the accumulation of electrons with higher reducing power. Moreover, Pd nanoparticles obviously improve the response range and intensity of the catalyst to sunlight. Therefore, the photocatalytic hydrogen production rate obviously increased. This work provides a reasonable method for designing efficient catalysts for photocatalytic hydrogen production.

Bottom-up synthesis of free-standing graphene using thermal plasma technology often results in flakes with smaller lateral dimensions (hundreds of nanometers) compared to top-down and substrate-based approaches (reaching centimeters in size) [1]. This limitation in size restricts the applicability of graphene in various applications. This study investigates a method to overcome this limitation by studying the reactor's quenching effect on the plasma plume exiting an RF-ICP thermal plasma torch. Local gas phase chemistry and graphene morphology were investigated during methane (CH4) pyrolysis in argon plasma. Natural quenching suppression led to a production of few-layer (2-5 layers), near-micrometer-sized un-supported graphene sheets (~2.8µm perimeter) with less crumpling and a projected area of (2-5)×105 nm². Raman, TEM, TGA, and XPS analysis confirmed the high quality of the synthesized graphene. Sp2 carbon composition in the sample was calculated using the D parameter obtained from the differentiated C KLL Auger peak in the XPS spectrum. A correlation between the gas phase chemistry and the graphene morphology demonstrated the significant effect of plasma reactor natural quenching and recirculation on the graphene synthesis and offers a potential for controlling the structure of unsupported graphene. The current study provides valuable insights that can pave the way for the development of reactors with a definite control over the morphology of synthesized graphene.

Metasurfaces (MSs), two-dimensional arrays of engineered nanostructures, have revolutionized optics by enabling precise manipulation of electromagnetic waves at subwavelength scales. These platforms offer unparalleled control over amplitude, phase, and polarization, unlocking advanced applications in imaging, communication, and sensing. Among them, plasmonic MSs stand out for their ability to exploit surface plasmon resonances (SPRs)—collective electron oscillations at metal-dielectric interfaces. This phenomenon enables extreme light confinement and field enhancement, leading to highly efficient light-matter interactions. The remarkable sensitivity of SPR to refractive index variations makes plasmonic MSs ideal for detecting minute biochemical and environmental changes with exceptional precision. Additionally, their tunable SPR characteristics enhance multifunctionality, enabling adaptive and real-time sensing. By leveraging these advantages, plasmonic MSs address critical challenges in modern sensing, driving breakthroughs in biomedical diagnostics, environmental monitoring, and chemical detection. This perspective explores recent advancements in plasmonic MSs, emphasizing flexible, multifunctional designs and the transformative role of artificial intelligence in optimizing performance and enabling real-time data analysis.

Two-dimensional (2D) semiconductors have received a lot of attention as the channel material for the next generation of transistors and electronic devices. On the other hand, insulating 2D gate dielectrics, as possible materials for gate dielectrics in transistors, have received little attention. We performed an experimental study on bismuth oxychloride, which is theoretically proposed to have good dielectric properties. High-quality bismuth oxychloride single crystals have been synthesized, and their high single crystallinity and spatial homogeneity have been thoroughly evidenced by x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, transmission electron microscopy (TEM), and scanning TEM studies. We then mechanically exfoliated high-quality BiOCl crystals to fabricate metal–insulator–metal (MIM) capacitors and measured the dielectric properties at various frequencies and different thicknesses. We found that BiOCl exhibits an out-of-plane static dielectric constant up to 11.6, which is 3 times higher than 2D hexagonal boron nitride making it a suitable candidate for 2D dielectrics. We also carried out cross-section TEM studies to look into the MIM interface and provide some future directions for their integration with metal-dielectric interfaces and possibly with other 2D devices.

Graphene Oxide (GO) is a two-dimensional (2D) nanomaterial largely exploited in many fields. Its preparation, usually performed from graphite in an oxidant environment, generally affords two-dimensional layers with a broad size distribution, with overoxidation easily occurring.
Here, we investigate the formation, along the Hummers synthesis of GO, of carbon nanoparticles isolated from GO and characterized through morphological and spectroscopic techniques. The purification methodology here applied is based on dialysis and results highly advantageous, since it does not involve chemical processes, which may lead to modifications in the composition of GO layers. Using a cross-matched characterization approach among different techniques, such as XPS, cyclic voltammetry and fluorescence spectroscopy, we demonstrate that the isolated carbon nanoparticles are constituted by layers that are highly oxidized at the edges and are stacked due to π-π interaction among their aromatic basal planes and H-bonded via their oxidized groups. These results, while representing a step forward in the comprehension of the structure of long-debated carbon debris in GO, strongly point to the introduction of dialysis as an indispensable step toward the preparation of more controlled and homogeneous GO layers and to its use for the valorization of low molecular weight GO species as luminescent carbon nanoparticles.

Bottom-up synthesis of free-standing graphene using thermal plasma technology often results in flakes with smaller lateral dimensions (hundreds of nanometers) compared to top-down and substrate-based approaches (reaching centimeters in size) [1]. This limitation in size restricts the applicability of graphene in various applications. This study investigates a method to overcome this limitation by studying the reactor's quenching effect on the plasma plume exiting an RF-ICP thermal plasma torch. Local gas phase chemistry and graphene morphology were investigated during methane (CH4) pyrolysis in argon plasma. Natural quenching suppression led to a production of few-layer (2-5 layers), near-micrometer-sized un-supported graphene sheets (~2.8µm perimeter) with less crumpling and a projected area of (2-5)×105 nm². Raman, TEM, TGA, and XPS analysis confirmed the high quality of the synthesized graphene. Sp2 carbon composition in the sample was calculated using the D parameter obtained from the differentiated C KLL Auger peak in the XPS spectrum. A correlation between the gas phase chemistry and the graphene morphology demonstrated the significant effect of plasma reactor natural quenching and recirculation on the graphene synthesis and offers a potential for controlling the structure of unsupported graphene. The current study provides valuable insights that can pave the way for the development of reactors with a definite control over the morphology of synthesized graphene.

To accurately achieve structure height differences in the range of single digit nanometres is of great importance for the fabrication of diffraction gratings for the extreme ultraviolet range (EUV). Here, structuring of silicon irradiated through a mask by a broad beam of helium ions with an energy of 30 keV was investigated as an alternative to conventional etching, which offers only limited controllability for shallow structures due to the higher rate of material removal. Utilising a broad ion beam allows for quick and cost effective fabrication. Ion fluence of the irradiations was varied in the range of 1e16 to 1e17 ions/cm². This enabled a fine tuning of structure height in the range of 1.00(5) to 20(1) nm, which is suitable for shallow gratings used in EUV applications. According to transmission electron microscopy investigations the observed structure shape is attributed to the formation of point defects and bubbles/cavities within the silicon. Diffraction capabilities of fabricated elements are experimentally shown at the SX700 beamline of BESSY II. Rigorous Maxwell solver simulation based on the finite-element method and rigorous coupled wave analysis are utilised to describe the experimental obtained diffraction pattern.

This study presents a detailed investigation into the fluorescence properties of color centers in single-crystal diamond needles (SCDNs) synthesized via chemical vapor deposition. Using steady-state and time-resolved photoluminescence techniques, we identified color centers with zero-phonon lines at 389 nm, 468 nm, 575 nm (NV⁰), 637 nm (NV⁻), and 738 nm (SiV⁻).
Photoluminescence excitation spectroscopy conducted at room temperature revealed the complex electronic structure of some of these centers, paving the way for further investigation into their fluorescence properties. Lifetime measurements were performed for each center, with the 389 nm one exhibiting the longest decay time (~30 ns), which is advantageous for enhancing quantum coherence, improving photon emission efficiency, and reducing power consumption. Altogether, these findings highlight the potential of SCDNs for quantum applications and confirm their promise as a platform for next-generation photonic and quantum devices.

Zero-dimensional (0D) quantum dots (QDs) and their hybrid structures having been rapidly developed are reshaping the design and performance of next generation ultrafast electronic and optoelectronic devices. The high-performance metrics achievable in photodetectors, solar cells, transistors, and other application areas can be realized through the use of quantum dots with their tunable electronic and optical properties. Recent advances in the synthesis of QD hybrid structures, where QDs are incorporated within other nanostructure dimensions (1D nanowires, 2D materials), have dramatically increased charge carrier mobility, lowered recombination rates, and resulted in highly controlled interfacial properties. Synergistic effects between these hybrid configurations are exploited, including improved charge separation and enhanced exciton dissociation, which are vital to realizing ultrafast response times and greater sensitivity. Advanced fabrication techniques such as chemical vapor deposition and solution based self-assembly, QD hybrids can be fabricated with highly controlled interfaces and optimal energy band alignments. Further, computational simulations such as Density Functional Theory (DFT) and time dependent DFT have provided further insights into the charge dynamics and electronic interactions in these hybrid systems for guidance on their design and application. The potential of QD-based hybrid architectures in addressing future information processing demands is demonstrated in this work, setting the stage for the development of high-speed, low-power devices in communications, sensing, and renewable energy technologies.

Nanochains made up of a one-dimensional arrangement of magnetic nanoparticles exhibit anisotropic properties with potential for various applications. Herein, using a novel self-assembly method we directly integrate single nanochains onto desired substrates including devices. We present a nanoscopic analysis of magnetization reversal in 1D linear nanoparticle arrays by combining X-ray microscopy, magnetoresistance, and micromagnetic simulations. Imaging the local magnetization along individual nanochains by scanning transmission X-ray microscopy and X-ray magnetic circular dichroism under varying in situ magnetic fields shows that each structure undergoes distinct non-homogeneous magnetization reversal processes. The experimental observations are complemented by micromagnetic simulations, revealing that morphological inhomogeneities critically influence the reversal process where regions with parallel chains or larger multi-domain particles act as nucleation centers for the magnetization switching and smaller particles provide pinning sites for the domain propagation. Magnetotransport through single nanochains reveals distinct magnetoresistance behavior that is correlated with the unique magnetization reversal processes dictated by the morphology of the structures. This study provides new insights into the complex magnetization reversal mechanism inherent to one-dimensional particle assemblies and the effective parameters that govern the process.

Over the past decade, graphene quantum dots (GQDs) have gained an inexhaustible deal of attention due to their unique zero-dimensional (0D) and quantum confinement properties, which boosted their wide research implication and reliable applications. As one of the promising 0D member and rising star of the carbon family, plant leaf-derived GQDs have attracted significant attention from scholars working in different research fields. Owing to its novel photophysical properties including high photo-stability, plant leaf-derived GQDs have been increasingly utilized in the fabrication of optoelectronic devices. Their superior biocompatibility finds their use in biotechnology applications, while their fascinating spin and magnetic properties have maximized their utilization in spin-manipulation devices. In order to promote the applications of plant leaf-derived GQDs in different fields, several studies over the past decade have successfully utilized plant leaf as sustainable precursor and synthesized GQDs with various sizes using different chemical and physical methods. In this review, we summarize the Neem and Fenugreek leaves based methods of synthesis of plant leaf-derived GQDs, discussing their surface characteristics and photophysical properties. We highlight the size and wavelength dependent photoluminescence properties of plant leaf-derived GQDs towards their applications in optoelectronic devices such as white light-emitting diodes and photodetectors, as well as biotechnology applications such as in vivo imaging of apoptotic cells and spin related devices as magnetic storage medium. Finally, we particularly discuss possible ways of fine tuning the spin properties of plant leaf-derived GQD clusters by incorporation with superconducting quantum interference device, followed by utilization of atomic force microscopy and magnetic force microscopy measurements for the construction of future spin-based magnetic storage media and spin manipulation quantum devices so as to provide an outlook on the future spin applications of plant leaf-derived GQDs.

Given the promising applications of large magnetoresistance in the Dirac semimetal cadmium arsenide (Cd₃As₂), extensive research into Si-compatible Cd₃As₂ devices is highly desirable. To prevent surface degradation and oxidation, the implementation of a protection layer on Cd₃As₂ is imperative. In this study, two vastly different protecting layers were prepared on top of two Cd₃As₂ samples. A zinc telluride layer was grown on top of one Cd₃As₂ film, giving rise to a ten-fold increased mobility, compared to that of the pristine Cd₃As₂ sample. Interestingly, unusual negative magnetoresistance is observed in the hexagonal boron nitride-capped Cd₃As₂ device when a magnetic field is applied perpendicularly to the Cd₃As₂ plane. This is in sharp contrast to the chiral anomaly that requires a magnetic field parallel to the Cd₃As₂ plane. We suggest that a protection layer on molecular beam epitaxy-grown Cd₃As₂ should be useful for realising its great device applications in magnetic sensing.