Single Nano Research Articles

In situ monitoring of electromigration in a single nano wire by picosecond ultrasonics

Recent nano-scale fabrication has realized the progress of integrated circuits, where current density increases with the downscaling of each electronic component, leading to failure due to electromigration. Electromigration is the transport of materials via momentum exchange from high-density conducting electrons to metal atoms. Defects of atoms result in the disconnection of the circuits and the accumulation of atoms causes the short circuit. Therefore, electromigration due to highly dense current flow has been studied for long years. However, it is difficult to non-destructively evaluate the structural and physical property changes due to the electromigration in an in-situ and microscopic measurement. In this study, we develop a real-time monitoring method of structural and mechanical property changes of a single nanowire using picosecond ultrasonics. Picosecond ultrasonics is ultrafast pump-probe laser ultrasonics using femtosecond pulse laser to excite and detect sub-THz ultrasound. We can focus the laser light within 1-micrometer diameter, enabling us to evaluate the mechanical property changes in a single nanowire from the ultrasound propagation. By applying direct current and observing ultrasound, we discuss the relationship among mechanical, electrical, and structural changes due to electromigration.

A novel microwall sliding test uncovering the origin of grain refined tribolayers

The tribology induced microstructure determines the tribological properties of metals. Yet the complex interaction of multiple microcontacts makes it impossible to decouple the fundamental plastic mechanisms. Single nano-/microasperity sliding tests allow to separate the microcontacts and to study the origins of plastic evolution during the initial stages of wear. However, the fundamental formation mechanisms of the sliding induced grain refinement are still largely unknown. In this work, we pre-remove material around the wear track and produce microwalls, which simplify the stress state and allow to directly inspect the contact zone. After sliding on the microwalls, a misorientation jump forms in the crystal orientation below the wear track. The crystallographic misorientation reaches 30° in some configurations, resulting in the formation of large angle grain boundaries. The misorientation jump formation depends on the grain orientation, wear direction and on twin boundaries in its path. We unravel the grain formation mechanism via slip-step and dislocation analysis and address dislocation arrangements at the grain boundary. This novel microwall sliding test has a potential to better understand the origins of microstructure modification in metals during the run-in stage of wear.

Semiconducting SWCNT Photo Detector for High Speed Switching Through Single Halo Doping

The method opted for accuracy, and no existing studies are based on this method. A design and characteristic survey of a new small band gap semiconducting Single Wall Carbon Nano Tube (SWCNT) Field Effect Transistor as a photodetector is carried out. In the proposed device, better performance is achieved by increasing the diameter and introducing a new single halo (SH) doping in the channel length of the CNTFET device. This paper is a study and analysis of the performance of a Carbon Nano Tube Field Effect Transistor (CNTFET) as a photodetector using the self-consistent Poisson and Green function method. The 2D self-consistent Poisson and Green’s function method for various optical intensities and wavelength simulate this proposed photodetector. The performance study is based on the simulation of drain current, transconductance, sub-threshold swing, cut-off frequency, gain, directivity, and quantum efficiency under dark and illuminated conditions. These quantum simulation results show that cut-off frequency increases while there is an increase in diameter. The proposed SH-CNTFET provides better performance in terms of higher gain and directivity than conventional CNTFET (C-CNTFET). This device will be helpful in optoelectronic integrated circuits (OEIC) receivers due to its superior performance.

Synthesis and characterization of high-entropy A2B2O7 pyrochlore with multiple elements at A and B sites

Single nano high-entropy pyrochlore-type compound (A2B2O7) with 7 different rare-earth cations at site A and 3 different metal cations at site B with equiatomic amounts (7A1/7)2(3B1/3)2O7 is successfully obtained. The powder with nominal composition (La1/7Sm1/7Nd1/7Pr1/7Y1/7Gd1/7Yb1/7)2(Sn1/3Hf1/3Zr1/3)2O7 was fabricated by reacting metal nitrates (site A) and metal chlorides (site B) with glycine during the combustion reaction. The XRD analysis revealed that the powder attained during synthesis is in an amorphous state. To induce crystallization of the obtained pyrochlore structure, the post-calcination process at 600-1500?C was conducted and studied. Results of this study showed that the monophase pyrochlore (A2B2O7) structure is obtained during the calcination at 900?C. The high-density ceramic pellet with 97% of theoretical density and free of any additives was obtained through pressureless sintering at 1650?C for 4 h in the air using the powder calcined at 900?C.

DIELECTRIC SPECTROSCOPIC ANALYSIS OF La0.75Ba0.25Fe1-XCOXO3(X = 0.0, 0.05, 0.1, 0.15, 0.20, 0.30)


 
 
 Single phase nano crystalline powder of La0.75Ba0.25Fe1-xCoxO3 for x ranging from 0.0-0.3 has been prepared using sol-gel method. For dielectric measurements, a steep decrease in the dielectric constant and dielectric has been observed in low frequency region, which tends to show no change at high frequency suggesting a usual dielectric dispersion. The observed dielectric dispersion behavior is directly related to the dipole moments produced due to mobility of localized charge carriers. The impedance measurements are used to show the grain boundary effects. Cole-Cole plot and frequency dependent conductivity measurements clearly demonstrate the conductive behavior of the ceramics.
 
 

Nanoarchitectonics of Indocyanine Green/Doxorubicin-Loaded Hydroxyl Boron Nitride Nanosheets for Chemophotothermal Therapy.

Biocompatible hydroxylated boron nitride nanosheets were effectively loaded with indocyanine green and doxorubicin using successive assembly. The indocyanine green/doxorubicin-loaded hydroxyl boron nitride nanosheets (ICG/DOX@OH-BNNS) integrated photothermal therapy and chemotherapy into a single nano vehicle. It had been confirmed that ICG/DOX@OH-BNNS could produce reactive oxygen species and exhibit excellent photothermal effects and light-triggered faster DOX release with NIR laser irradiation. On the other hand, the fluorescence of DOX in ICG/DOX@OH-BNNS was also used for visualizing subcellular location. Compared with individual chemotherapy and photothermal therapy, the combined treatment of ICG/DOX@OH-BNNS could synergistically induce the apoptosis and death of A549 cells and suppress S180 tumor growth in vivo.

Quercetin Nanoparticles- A Promising Approach to Cancer Treatment: A Review

Quercetin, a naturally occurring polyphenolic element, has rapidly received attention as an anticancer agent. Although quercetin has demonstrated potent medical value, its application as an antitumor drug is limited because of poor solubility, low absorption, and fat metabolism. Nanoparticles are effective and versatile drug delivery devices because they can improve the solubility, pharmacokinetics, bio distribution, and in vivo stability of the free drug. The utilization of Nano-carrier scanning increases the bioavailability of the drug. Quercetin nanoparticles have shown high encapsulation efficiency, stability, sustained release, extended circulation time, improved accumulation at tumor sites, and therapeutic efficacy. This review article aims to estimate the anticancer efficiency of polymeric nanoparticles of quercetin. The majority of research is based on the preclinical anticancer activities of quercetin nanoparticles. MCF cells of breast cancer (BC), A 549 cells of lung cancer, cells of HepG2 liver malignancy, and cells of malignance are the primary targets for possible anticancer activity. Furthermore, combining quercetin with other diagnostic or therapeutic agents in a single Nano carrier has resulted in improvements in tumor detection or treatment. The antitumor outcome of drugs that are used in cancer therapy can also be supported by quercetin nanoparticles by increasing the anti-tumor development or decreasing the systemic toxicity level of the drug. Keywords: , , ,

Thermal Management of Solar Photovoltaic Cell by Using Single Walled Carbon Nanotube (SWCNT)/Water: Numerical Simulation and Sensitivity Analysis

Despite the attractiveness of Photovoltaic (PV) cells for electrification and supplying power in term of environmental criteria and fuel saving, their efficiency is relatively low and is further decreased by temperature increment, as a consequence of absorption of solar radiation. In order to prevent efficiency degradation of solar cells due to temperature increment, thermal management is suggested. Active cooling of solar cells with use of liquid flow is one of the most conventional techniques used in recent years. By use of nanofluids with improved thermophysical properties, the efficiency of this cooling approach is improvable. In this article, Single Walled Carbon Nano Tube (SWCNT)/water nanofluid is used for cooling of a PV cell by considering variations in different factors such as volume fraction of solid phase, solar radiation, ambient temperature and mass flow rate. According to the findings, use of the nanofluid can lead to improvement in performance enhancement; however, this is not significant compared with water. In cases using water and the nanofluid at 0.5% and 1% concentrations, the maximum improvement in the efficiency of the cell compared with the cell without cooing were 49.2%, 49.3 and 49.4%, respectively. In addition, sensitivity analysis was performed on the performance enhancement of the cell and it was noticed that solar radiation has the highest impact on the performance enhancement by using the applied cooling technique, followed by ambient temperature, mass flow rate of the coolants and concentration of the nanofluid, respectively. Moreover, exergy analysis is implemented on the system and it is noticed that lower ambient temperature and solar radiation are preferred in term of exergy efficiency.

Phase‐Only Holographic Assisted Planar Printing for Massively Multiplexed Optical Display and Encryption

AbstractMultiplexed planar printings, made of single or few layer micro and nano optical platforms, are essential for high capacity display, information storage, and encryption. Although they are developed rapidly, the demonstrated channels are still limited and also lack instantaneity. Here, holograms and printings, always regarded as two independent information coding domains with totally different principles, are combined together through this proposed angle multiplexing framework, leading to multiplexed printings with hundreds of channels. Based on such approach, the authors experimentally encode, respectively, 25 gray scale printings into 25 angles and even 8 gray scale videos into 8 angles with a phase‐only spatial light modulator. As a bridge between printings and holograms, this method allows to generate printings combining various holographic methods. Beneficial from this, a gradient metasurface based 324 channel printing is demonstrated which multiplexes angles, polarizations, and wavelengths simultaneously. This work paves the way to flexibly angle‐dependent printing display and massively multiplexed encryption systems.

Enhanced spin wave coupling between array of spin torque nano oscillators in magnonic crystal cavities

Spin wave coupling between nano contact spin torque nano oscllators in asymmetric and symmetric array of antidot MC cavities to obtain sustained spin wave oscillations using supercell plane wave method and micromagnetics is discussed. The SWs were excited by injecting a spin-polarized current into a single nano contact in a L3 magnonic crystal cavity(MCC) and radiate like an end-fire antenna. The SW oscillations are then coupled into one of the guided modes of a magnonic crystal waveguide (MCW). The MCC acts as a SW resonator and spin-torque injection as gain. Together they achieve sustainable oscillations in a manner analogous to the behavior of a laser cavity. The phase locking of arrays of cavities arranged symmetrically and asymmetrically on both sides of a MCW is also discussed. Spin waves are radiated like a broadside antenna. The PSD of the broadside case is 28 dB lower than that of the end-fire case. The obtained value from the micromagnetic simulation is used to find the corresponding point in the guided mode of MCW, and this occurs nearer to the edge of the Brillouin zone. We also investigated the point in dispersion where the maximum energy is coupled from MCC to MCW. The spectral characteristics of the broadside coupling were correlated with frequency pulling effects in the laser cavity. Asymmetric spin-torque excitations on either sides of the MCW cause odd frequency peaks in the PSD characteristics. This can be mitigated when we use MC cavities placed symmetrically on both sides of the MCW, and excite spin waves in each cavity. However, spin waves excited in an asymmetric array of cavities add in phase, yielding a power enhancement with an increase in the number of cavities. Spin waves excited in a symmetric array of cavities add out of phase and result in spin-wave decoherence with an increase in the number of cavities.

Tunable magnetization of single domain M-type barium hexagonal ferrite nano powders by Co–Ti substitution via chemical co-precipitation plus molten salts method

To satisfy the requirement of designing magnetic flexible composites, Co–Ti co-substituted M-type barium hexagonal ferrite nano powders with tunable magnetization have been successfully fabricated by a chemical coprecipitation plus molten salts method. The molten salts provide a liquid phase for phase formation and crystal growth of the targeted doped ferrite phases, leading to the formation of nano powders consisting of single domain particles with less agglomerations and particle size ranging from 60 to 100 nm. The co-doping of Co2+ and Ti4+ in the ferrites reduces their axial magnetic anisotropy, resulting in tunable magnetic properties from hard to soft magnetization.

On analysis of magnetized viscous fluid flow in permeable channel with single wall carbon nano tubes dispersion by executing nano-layer approach

The prime motive of this pagination is to adumbrate attributes of water-based hybrid nanoliquid flow with dispersion of single wall carbon nanotubes. An innovative thermal conductance model containing the aspects of nanolayer formation along with shape and size of inserted particles is obliged. Flow transport mechanism is addressed mathematically in the form Navier Stokes equations with magnetization. In addition, heat and mass transport mechanism is manipulated by considering the impression of viscous dissipation and chemical reactions. Walls of channels are assumed to be porous in order to examine the phenomenon of suction and injection. Mathematical formulation of problem is represented in view of ODE’s and simulated computationally by Keller Box scheme. Subsequently, Newton method is utilized to solve system of nonlinear equations. Results are revealed through graphs and tables showing behavior of associated momentum, temperature and concentration profile against involved parameters. Quantities of engineering interest like wall drag coefficient, heat and mass fluxes are computed. Credibility of work is shown by creating match with existing study and an excellent agreement is found. After thorough analysis it is determined that heat flux increases with induction of single wall carbon nanotubes in base liquid. It is also manifested that thermal conductance of base fluid enriches with increase in thickness of nanolayer and radius of particles. In addition, positive trend in skin friction and heat flux coefficients is measured against elevation in nanoparticle volume fraction. Opposite behavior in velocity and temperature distributions against all flow variables near upper and lower walls of channel is depicted due to provision suction and injection wall velocities. Due to consideration of viscous dissipation heat transfer rate with in the flow domain reduces. By increasing Reynold number concentration distribution diminishes due to dominant effect of inertial forces. Decline in momentum distribution against Hall current parameter is adhered. Uplift and decrement in temperature distribution is manifested against heat source and sink parameters respectively.

Polymer-Based Materials and their Applications in Image-Guided Cancer Therapy.

Advances in nanotechnology have enabled the combination of disease diagnosis and therapy into a single nano package that has tremendous potential for the development of new theranostic strategies. The variety of polymer-based materials has grown exponentially over the past several decades. Such materials have great potential as carriers in disease detection imaging and image monitoring and in systems for the precise delivery of drugs to specific target sites. In the present article, we review recent key developments in the synthesis of polymer- based materials for various medical applications and their clinical trials. There is a growing range of multi-faceted, polymer-based materials with various functions. These functions include carriers for image contrast agents, drug delivery systems, and real-time image-guided systems for noninvasive or minimally invasive therapeutic procedures for cancer therapy.

Biofabricated nanoparticles: Their delivery and utility in Plutella xylostella management

The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae) is one of the most serious cosmopolitan pests of cruciferous plants. It causes severe damage to crop quality and production, with estimated global losses of 20-40% per year. Consumer preference regarding pest-free and uncontaminated crop, unavailability of highly competitive natural enemies as well as migratory nature of DBM has obligated for the mandatory use of insecticides. The over reliance and indiscriminate use of chemical insecticides to control DBM has lead to development of resistance against almost all the modern insecticides. In addition, it has also developed resistance against most of the Bt strain. To overcome the problem of resistance, there is an urgent need for new and highly efficient method to control DBM which must be eco-friendly, cost effective and has minimum impact on the environment. One of such alternatives is nanotechnology which fulfil all the criteria to become an ideal insecticide or delivery system for insect pest management especially DBM. Nanotechnology offers great improvement in the field of pesticides as it is less toxic, shelf-life enhancement and higher water solubility. Loading of Indoxacarb on nanoparticles are reported to be highly effective they suppressed the activity of detoxification enzymes such as GST, CarE, and P450. Green synthesis of AgNPs, Single walled carbon nano tube (SWCNT) also exhibits larvicidal and pupicidal effect. These are also reported to adversely affect food consumption, growth, pupation and fecundity of P. xylostella.These nanoparticles have been found to be more stable, also the controlled release of active ingredient for a long time and provides target specific control of P. xylostella for solving adverse situations ofthe crop fields like less food security, lesser food productivity and environmental imbalance.

Ab initio study of fullerene based single molecule nano junctions

In this paper, we explored various fullerene molecules (C20 and impurity added C20) based single molecule nano-junctions using ab initio framework with density functional theory (DFT). In coulomb regime, various fullerenes are placed over the dielectric, in between source and drain for weaker coupling. The HOMO, LUMO values, charge stability diagrams and total energy vs. gate voltage of pristine and impurity added fullerene nano-junction (IAF) are studied. The conductive behaviour of pristine and IAF in coulomb blockade regime are addressed. This work features the fullerene based materials in molecular nano-junctions for ultrahigh speed switching and sensing applications.

Design of Cylindrical Surrounding Double-Gate MOSFET With Fabrication Steps Using a Layer-by-Layer Approach

The semiconductors with nanometer-scale are subjected to various patterns and scaling using the latest technology. The most widely used methods are top-down approaches in the design of complex heterostructures. The top-down approach involves the photolithography to ion sequentially beaming of the materials. In this context, the alternative layer-by-layer approach with cylindrical structures has been discussed and supported by the subsequent results to make Cylindrical Surrounding Double-Gate (CSDG) MOSFETs in this research work. This method involves the making of cylindrical structures with high-resolution morphological structures of CSDG MOSFETs. The process has been described in detail to design the CSDG MOSFETs with high-ƙ dielectric materials to make them suitable for low-frequency RF applications. The fast modulation of the Single Nano Wire (SNW) has been adopted for complex heterostructure modeling. The high-ƙ dielectric materials are placed in between the spacer and the gate material to overcome the Short Channel Effects (SCEs). This method produces symmetrical and concentric cylindrical structures of the CSDG MOSFETs with suitable layers. The minimum layer thickness achieved is about 10 nm axial length along with the core of the SNW. This gives enough insight for the proposed cylindrical structure to fabricate over the core of 2DEG. In this type of structure development, many cylindrical structures with various properties can be designed. The parameters focused on the cylindrical structure will be periodic, non-periodic, symmetric, asymmetric structures, and gaps/dots of nanometer scale. This innovative method introduces the method of designing the symmetric CSDG MOSFET concerning the center core. In this work, the authors focus on the suitable novel technique of designing cylindrical structures with unique dimensions and physical properties using various semiconductor materials.

Effect of alumina/graphene hybrid nano reinforcement to the adhesion and mechanical properties of adhesively bonded aluminum alloy with epoxy

In present work, an attempt has been made to investigate the effect of alumina and graphene nanoplatelets (GNP) hybrid nano reinforcement to the wetting behavior and mechanical property of adhesively joint aluminum alloy with epoxy adhesive. Alumina-GNP hybrid nano adhesive at 1.0 wt% concentration with various weight ratio combination (i.e.: 10:0, 7:3, 5:5, 3:7, 0:10) was adopted into two components structural epoxy adhesive to bond 7075-T6 aluminum alloy. When compared to pristine adhesive, hybrid nano adhesive has shown two distinct trends with regard to the spread area behavior: (i) hybrid nano adhesive at 7:3 and 5:5 wt ratio combination exhibits a reduction of spread area up to 71.59 % and 48.07% respectively while (ii) hybrid nano adhesive at 3:7 wt ratio combination has shown an increase of spread up to 31.58%. It is also observed that the incorporation of hybrid nano reinforcement at 7:3 wt ratio combination has demonstrated highest shear strength up to 42.29% as compared to the pristine adhesive counterpart. Moreover, as compared to specimens with single alumina and GNP nano adhesives (i.e.: 10:0 and 0:10 wt ratio), specimens with hybrid nano adhesive at 7:3 wt ratio demonstrates an improved shear strength up to 61.48% and 101.2%, respectively. In current work, it has been observed that regardless of alumina-GNP weight ratio combination, all fractured specimens demonstrated the combination of adhesive and cohesive fractures behavior.

Antimicrobial Activities of Single Nano particle (SNPs) & Core-shell Nanomaterials (CSNMs) with Special Reference to Binding Mechanisms

Antimicrobial Activities of Single Nano particle (SNPs) & Core-shell Nanomaterials (CSNMs) with Special Reference to Binding Mechanisms

Direct thermal decomposition of FeCl3.6H2O in oleic acid forms hematite cube and nano octahedron structure with quasicrystalline and supercell symmetries for enhanced photoelectrochemical functionality

The direct formation of hematite nanostructures by the thermal decomposition of precursor salt in the oleic acid is discussed here. The obtained nanostructures show interesting structural properties with the unique presence of quasicrystalline and supercell symmetries. The quasicrystalline symmetry obtained is of 2- fold and 3-fold icosahedral symmetries. HRTEM study of the single nano octahedron each faces reveals different axis of symmetry along with the presence of 2-fold icosahedral quasicrystal. The synthesis route results well distributed hematite nano octahedron, where urea plays a role in controlling its distribution as confirmed by FESEM studies. Next, a mechanism is proposed for how 24 h aged Hematite nano octahedron decays with increased acidity of the reaction medium in the presence of urea? It is found that the Urea deprotonated first and keep the nano octahedron morphology stable depending on the salt to urea molar ratio. Finally, the photoelectrochemical properties of the hematite nano octahedron film is studied, and a photocurrent density of 200 μA/cm2 is obtained for non -Urea mediated one (24 O. A.). From the XRD comparison of both films (24 h and 24 O.A.), it is found that (110) Bragg plane diffracted intensity increases without Urea, which helps in the enhancement of the photocurrent density due to a well-established electronic conductivity of Hematite along (001) Basal plane.

Scanning electrochemical cell microscopy for the study of (nano)particle electrochemistry: From the sub‐particle to ensemble level

AbstractScanning electrochemical cell microscopy (SECCM) is a scanning‐droplet‐based technique that allows electrochemical fluxes and/or interfacial reactivity to be measured and visualized with high spatiotemporal resolution. This minireview spotlights the use of SECCM for studying the electrochemistry of (nano)particles, highlighting recent works spanning multiple timescales (i.e., microseconds to seconds) and lengthscales (i.e., nanometers to micrometers) to probe physicochemical phenomena at the sub‐particle, single particle, and/or (micro)ensemble levels. In SECCM, single (nano)particles (or small particle ensembles) are electrochemically interrogated—directly from colloidal solution (i.e., by investigating electrochemical nanoimpacts with a substrate electrode) or supported on an electrochemically inert support electrode—with a pipette probe that is operated in either a stationary (point measurement) or dynamic scanning/imaging mode. Nanoscale‐resolved electrochemical information (e.g., local rates of electron‐ or ion‐transfer, catalytic activity, corrosion resistance, etc.) from SECCM is readily related to (nano)particle structure and properties, collected at a commensurate scale with complementary, co‐located microscopy/spectroscopy techniques, allowing structure and function to be resolved directly and unambiguously down to the sub‐particle level. Understanding structure−function on this scale enables macroscopic “particle‐on‐support” electrode behavior to be rationalized and further predicted, guiding the discovery, design, and engineering of novel electromaterials with enhanced function, which is a “holy grail” in materials science.