Atomic-force microscopy (AFM) is a type of scanning probe microscopy. It possesses nano-scale resolution which is >1000 times better than the optical diffraction limit. An image of AFM is the result of interaction between the tip and the sample. The AFM image is not accurate and distorted due to the finite size of the probe tip. To correct the AFM image and acquire accurate sample morphology information, it needs to evaluate the tip shape and status. The shape of the probe tip is calculated to determine the quality of the probe. The optical glass surface fabricated by free abrasive polishing (traditional mechanical polishing) technique is used as a new tip characteriser to calibrate the AFM probe tip. Meanwhile, an improved blind reconstruction algorithm is adopted to calculate the AFM tip shape and size. In the help of matrices, the blind reconstruction algorithm is elaborated clearly. The optical glass surface with irregular nanostructures ensures that the morphology of probe tip can be determined accurately. Without independent knowledge of the sample morphology, the three-dimensional morphology of the AFM tip can be obtained.

Magnetically separable CoFe₂O₄/reduced graphene oxide (CoFe₂O₄/RGO) and a new of magnetic hydroxyapatite/CoFe₂O₄/RGO nanocomposites (HAp/CoFe₂O₄/RGO) were prepared via co-precipitation along with hydrothermal methods. The characterisation and properties of the synthesised nanocomposite were analysed using Fourier transform infrared, X-ray powder diffraction, vibrating sample magnetometer, field emission scanning electron microscopy, transmission electron microscopy (TEM) and UV-visible spectroscopy. TEM images show that the synthetic RGO layers are decorated with 10 nm CoFe₂O₄ particles and HAp nanorods of about 10 nm diameter and 100 nm average length are well separated and uniformly distributed. In addition, separation of the layers from one another and approximately uniform distribution on nanosheets is completely visible. Due to the magnetic properties of HAp/CoFe₂O₄/RGO nanocomposite, it can be separated from the environment by an external magnetic field. In addition, the energy gap measurements represent the effective role of CoFe₂O₄/RGO inremarkable decreasing of the energy gap of the nano-HAp.

In this study, the influence of spontaneous and piezo-phototronic effect on the performance of hexagonal and triangular III-Nitride nanowire (NW) photovoltaic devices are investigated. The effect of stress/strain distribution on band structure of GaN/In_xGa_1-xN/GaN core/shell/shell NW solar cell with hexagonal and triangular geometrical shape are also intensively investigated by numerical calculations. It is observed that NW solar cells possess a non-uniform pattern of polarisation charges (PCs) due to complex distribution of strain and stress parameters depending upon growth orientations of NWs. Effect of PCs, especially due to piezo-phototronic effect on the polar, semi-polar and non-polar planes of NW having Miller–Bravais indices of {000-1}, {1-101} and {1-100} are discussed in detail, respectively. This numerical study not only provides the basic theoretical understanding about the spontaneous and piezo-phototronic effect on III-Nitride solar cell but also assists to obtain most optimised geometrical design to achieve high performance NW solar cell.

This work aims at the manipulation of nanoscopic voltage produced through uniform and non-uniform rubbing in neat unpolarised polymer polyvinylidene fluoride. A metal–insulator configuration is considered for the analysis. The decay of surface potential in such a configuration is also addressed in this work. The polarity of the voltage observed on the film depends on the work function of the metal electrode in contact as well as the electronegativity of polymeric material under study. Scanning probe microscopic techniques such as dynamic contact mode electrostatic force microscopy, scanning tunnelling microscopy are used for the investigation of specific electrostatic potential variation on polymer films. Effect of contact electrification leads to nanoscopic domains of voltage generation on the surface of the tribolayers. Electrostatic potential developed on the surface of unrubbed polymer film using modulated tip is in the range of 20–40 mV. The range of voltage generated increased from 20 to 125 mV in the case of rubbed polymer films. Charge retention is discussed through obtaining surface potential decay trend at various intervals. This also plays an important role in the generation of the voltage as well as the current. The above scenario has been demonstrated in both rubbed and unrubbed scenarios. Charge decay is observed to be gradually decreasing from 40 to 29.5 mV in unrubbed surface and 125 to 14 mV in rubbed surface for various time intervals. The obtained results suggest insignificance of triboelectric series on contact electrification between similar tribolayers.

Service performance of nanopins based on different branched carbon nanotubes (CNTs) including the 45° Y-type CNT, the 45° V-type CNT, the 90° Y-type CNT, and the T-type CNT have been investigated using classical molecular dynamics simulations. The Y-type CNT is the most cost-effective while there is adequate room to improve its service performance. The installed V-type CNT always has a trend of leaving from the silicon hole, and thus it would better be used with another nanopin cooperatively. For the 90° Y-type CNT, the installation resistance and the unloading force are almost in the same order of magnitude while the installation in pushing approach is relatively easier than that in pulling approach. Interestingly, the attraction between the silicon hole and the T-type CNT can mislead the branch, resulting in the failed installation of the T-type CNT consequently.

Owing to low-electronic conductivity and long lithium ion diffusion path of NH₄V₃O₈ limit its application for lithium-ion batteries (LIBs). To overcome these limitation, a new nano-composites material of NH₄V₃O₈-based have been successfully fabricated by a facial and environmental friendly approach, without the addition of any other template or surfactant. A facile hydrothermal route is employed to synthesised the reduced graphene oxide(rGO)/NH₄V₃O₈ composites. Results show that the NH₄V₃O₈ nano-belt are well distributed on the surface of rGO nanosheets. The resulted rGO/NH₄V₃O₈ nanocomposites exhibit a high capacity as a cathode material for LIBs in comparison with the bare NH₄V₃O₈.When used as cathode material for LIBs, it delivers a maximum discharge capacity of 253 mAhg⁻¹ at 15 mAg⁻¹, 70 mAhg⁻¹ larger than that of the pristine one. The enhanced electrochemical performance is attributed to the synergetic effects between NH₄V₃O₈ and rGO, such as increased conductivity and shortened lithium ion diffusion path.

BiIO₄/Bi₂O₂(BO₂OH) heterostructure is successfully synthesised by the method of one-step hydrothermal treatment. Characterisation of BiIO₄/Bi₂O₂(BO₂OH) heterostructure is performed by X-ray diffraction, scanning electron microscope, transmission electron microscopy and ultraviolet (UV)–visible diffuse reflectance. The photocatalytic activity is measured by the decomposition of rhodamine B under UV light irradiation. Compared with Bi₂O₂(BO₂OH), BiIO₄ and P25, it is noted that 35 wt% BiIO₄/Bi₂O₂(BO₂OH) exhibits better performance on degradation. The type-II band alignment of the heterostructure and the decreased recombination rate of electron–hole pairs contribute to this significant enhancement of decomposition of organic contaminations.

N-cyclohexyl-2-benzothiazole sulphonamide (rubber vulcanisation accelerator CZ) was grafted onto the surface of dispersible nano-silica (DNS) to obtain silica-loaded rubber vulcanisation accelerator CZ (DNS-CZ) through in-situ surface modification. A series of as-prepared DNS-CZ samples with different CZ loadings were used as the fillers to reinforce the composites made of solution styrene-butadiene rubber (SSBR) and butadiene rubber (BR). The effect of DNS-CZ fillers on the mechanical properties of the SSBR/BR composites was investigated in relation to the scanning electron microscopic observation of the filler dispersion in the rubber matrix. It was found that the CZ is chemically bonded onto the surface of nano-silica, thereby effectively reducing the polarity of the nano-silica and enhancing its compatibility with the rubber matrix. Therefore, the SSBR/BR composites filled with DNS-CZ exhibit greatly improved mechanical properties and Akron abrasion resistance than the counterparts filled with unloaded DNS. Particularly, when the loading amount of the CZ is set as 81.10 mmol/kg, the resultant SSBR/BR/DNS-CZ composite exhibits the best mechanical properties and Akron abrasion resistance, showing promising application for green tire tread.

The Letter presents the results of characterisation of intercalated and exfoliated graphite. The electrochemically exfoliated graphite (EEG) was synthesised in solution containing sulphuric acid and potassium chlorate(V). The number of graphene layers, degree of disordering and the presence of functional groups were determined using X-ray diffraction method, Raman spectroscopy, Fourier transform infrared spectroscopy and UV–visible spectroscopy. High-resolution transmission electron microscopy and scanning electron microscopy were used to imaging morphology and structure of the synthesised material. The obtained micrographs indicate the presence of highly disordered areas near the edge of flakes and in-plane ordered lattice structure in the flat zone between disordered areas. X-ray diffraction patterns clearly indicate the presence of both nanographite and graphene oxide. The EEG was also characterised by relatively high thermal stability, which was confirmed using thermogravimetric analysis.

NiCoP with an urchin-like structure was successfully synthesised by a facile solvothermal route and characterised by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that NiCoP was a single crystal structure, composed of a large number of urchin-like structures and few spherical structures. In addition, a few hollow urchins-likes were observed. Moreover, many nanorods self-assembled on the surface of the urchin-like NiCoP, with lengths of 300–500 nm and a diameter of 20 nm. The novel NiCoP nuclei were aggregated into spherical particles that gradually grew into hollow urchin-like structures via Ostwald ripening. In addition, NiCoP has good adsorption properties and can absorb some organic dyes, like Malachite green and Congo red.

A novel nanocomposite, H₄SiW₁₂O₄₀ immobilised magnetic chitosan (HSiW-MC) was prepared via a facile procedure in one-pot fashion. This composite was fully characterised using several methods including, Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy and scanning electron microscopy. It was applied as a novel catalyst in two three components reaction involving, dimedone, differently substituted aryl aldehydes and either 3-amino-1,2,4-triazole or 2-amino benzimidazole to afford the corresponding [1,2,4]triazolo/benzimidazolo quinazolinone derivatives. It showed excellent performance in the aforementioned reaction with the high yield of 96%. Also, the effect of HSiW-MC amount, catalysts, solvents and temperatures were studied and the best results were obtained in CH₃CN in the presence of HSiW-MC (0.04 g) under refluxing conditions.

The traditional use of Scotch tape for exfoliating layers of two-dimensional (2D) transition metal dichalcogenides (TMDs) has been compared with a gel-assisted mechanical exfoliation technique, using MoS₂ as a representative TMD. The gel-assisted exfoliation process, which makes use of both Scotch tape and a gel film, is superior to the use of Scotch tape alone, as it gives a higher probability of obtaining larger surface area few-layer flakes. A quantitative analysis has been made between the samples prepared by the two techniques. The total density of flakes transferred onto a sample by Scotch tape alone was much higher than when using the gel film. However, most of the transferred flakes were several microns in thickness with lateral dimensions <10 µm. Therefore, the higher percentage of few-layer flakes with large lateral dimensions (> 20 µm) transferred using gel film is very advantageous. Since samples prepared using gel film have fewer flakes, the contacting of potential thin flakes on the sample can be done conveniently. Also, unlike Scotch tape, the gel film does not leave adhesive residue on the substrate. Optical microscopy, contrast difference measurements and Raman spectroscopy were used for identification of the few-layer MoS₂ flakes.

Three-dimensional (3D) zinc oxide (ZnO) rod-like structures loaded with silver (Ag) nanoparticles (3D Ag/ZnO RLS) have been successfully synthesised by a facile hydrothermal and microwave method. The successful loading of Ag nanoparticles and the 3D hierarchical structure were characterised by scanning electron microscopy and X-ray diffraction. The pHs of zero point charge were 7.8 and 7.9 for 3D ZnO rod-like structures (3D ZnO RLS) and 3D Ag/ZnO RLS, respectively. The photocatalytic performances of the 3D RLS were evaluated by decomposing methylene blue under ultraviolet irradiation. Compared to 3D ZnO RLS, the enhanced photocatalytic performance of 3D Ag/ZnO RLS may be attributed to the 3D hierarchical structure of the Ag/ZnO, as the structure can lead to enhanced light absorption and lower recombination of photoinduced holes and electrons.

Three silver-based photocatalysts, Ag@AgBr, Ag₂Mo₂O₇, and Ag₂MoO₄-MoO₃, were successfully synthesised by a smart hydrothermal strategy using molybdenum oxide as precursor in surfactant-assisted processes. The correlation among crystal structure and properties in the photocatalysts are discussed in detail. In addition to morphology control, the bromine source effect of adding surfactant cetyltrimethyl ammonium bromide in hydrothermal synthesis of plasmonic silver incorporated silver bromide photocatalyst was also found. The obtained Ag@AgBr showed higher photocatalytic activity in the degradation of methylene blue than other samples due to super sensitivity of AgBr to light and the surface plasmon resonance of Ag nanoparticles in the region of visible light.

A unique design for an asymmetrical underlap (AU) cylindrical-gate-all-around (GAA)-n-tunnel field effect transistor (TFET) based on hetero-spacer engineering with trap-assisted tunnelling (TAT) for reliability concern is proposed and validated. Here, DC and analogue performances such as I _ON, I _OFF, SS, I _ON /I _OFF, C _gs, and C _gd have been investigated, while included TAT model and compared the examined device with AU GAA-TFET based on homo-spacer (HS) dielectric. On the basis of observation, the proposed device increases ON current as high as 2.1 × 10⁻⁶ A/µm, which corresponds to 1024 times improvement in I _ON /I _OFF when compared with device based on HS. It also suppresses ambipolar behaviour with fast switching ON–OFF transition due to low leakage current (I _OFF). These performances are mainly produced due to AU and low-k spacer dielectric which is replaced by high-k dielectric over source side spacer of the device, whereas drain side spacer is placed with high-k material along with increase in series resistance across drain–channel junction caused by drain underlap. Low-k spacer reduces the fringing field, and the depletion does not form at the source–gate edge, hence high source–channel tunnelling junction.

Single-crystalline two-dimensional (2D) nickel oxide (NiO) porous nanobiscuits with diameters of 100–210 nm, thicknesses of 10–20 nm and pore sizes of <20 nm are fabricated through a low-cost water bath combined with calcination treatment approach. The composition and morphology of the products are characterised by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, selected area electronic diffraction and N₂ adsorption/desorption. The possible formation mechanism of single-crystalline porous NiO nanobiscuits is simply discussed. Served as adsorbent, the as-prepared single-crystalline porous NiO nanobiscuits exhibited excellent performance for the fast removal of Congo red from water, which is far beyond the adsorption rate of activated carbon. The results show that the adsorption isotherm fits well with Langmuir adsorption model. The maximum adsorption capacity is calculated to be 193.2 mg g⁻¹, which is larger than that of other reported 2D NiO architectures.

A three-dimensional (3D) graphene hydrogel covered by uniform silver nanoparticles as an effective substrate for surface-enhanced Raman scattering application was fabricated by facile ethylenediamine-induced self-assembly method. The anchor of silver nanoparticles endows the enhanced Raman spectroscopy with the sensitivity and multiplex requirements for the tellurium quick detection using the robust graphene-based monoliths. The porous structure offers essential channels and space for Te(IV) access. After exposure to Te(IV), the distinguished peak of Te-O at 584.9 cm⁻¹, which was enhanced significantly and kept constant over a wide range of pH, was selected as the indicative of Te(IV) level. At the optimal pH, the concentration dependent surface-enhanced Raman spectroscopy shows that the detection limit was as low as 100 nM.

A simple self-sacrificed template method was used to prepare a polypyrrole (PPy) nanotubes sensor for the detection of ammonia (NH₃). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyse the morphology of the fabricated membrane. The results show that pyrrole was uniformly polymerised around the sodium vanadate (Na₅V₁₂O₃₂) nanowires, and the Na₅V₁₂O₃₂ nanowires along with Ti foil were subsequently dissolved thoroughly with citric acid (0.5 M) and hydrofluoric acid (10%, v/v) to obtain a freestanding flexible PPy nanotube membrane. The resulting PPy membrane was sensitive to NH₃ and exhibited rapid and reproducible response at room temperature.

Water wettability patterns on superhydrophobic surfaces have been widely designed to meet requirements of many fields, such as lab-on-a-chip devices and bioengineering. However, these systems are easily invalidated by oily liquids. Therefore, oil wettability patterns, which have rarely been focused on, are urgently needed. In this work, the authors successfully control oil wettability of superoleophobic surface by an atmospheric pressure dielectric barrier discharge (DBD) plasma jet. The results indicate that oil wettability is strongly influenced by treatment time, applied voltage and distance between plasma jet outlet and samples. They find that superoleophobic surfaces can be modified to be superoleophilic within 15 s, and that small holes can be etched on the surfaces under high applied voltages. Then, superoleophobic-superoleophilic patterns are prepared via selective plasma jet irradiation on superoleophobic surfaces, and both directional and antigravity transport of water and oily liquids are thus realised without external electrical or magnetic field. Additionally, ageing experiments show that the plasma-treated areas can maintain the induced wettability for >30 days storing under normal ambients, demonstrating superior time stability. The results presented here show the potential of atmospheric pressure DBD plasma jet for rapid oil wettability control and fabrication of long-time-effective oil wettability patterns.

Novel periodic mesoporous organosilicas (PMOs) as functional nanomaterials based on the skeleton of lysine were synthesised by the co-condensation of lysine-bridged organosilicane (Lys-BOS) and tetraethyl orthosilicate in acidic medium using P123 as template. Furthermore, a large content of Lys-BOS was incorporated into the silica framework. Amino acid organosilicane (Lys-BOS) was first prepared by the multi-step reaction between traditional orgnaosilicane [(3-aminopropyl) triethoxysilane] and carboxyl protected lysine. The small-angle X-ray diffraction and N₂ adsorption–desorption isotherms indicate that these PMO materials still retain ordered mesostructure in the high molar concentration of Lys-BOS. Fourier-transform infrared spectroscopy confirms that lysine is incorporated in the framework of the PMO materials.

This study investigates the effects of the scratching trajectory and the feed direction on the formation of ripple structure on the surface of polymer material using atomic force microscope (AFM) tip-based nanomachining approach. Nanoscratching tests are carried out using a diamond AFM tip by single scanning method. Nine typical combining scratching trajectories and feed directions are illustrated. The stick-slip and crack formation processes are used to explain the formation mechanism of the ripple structure for different scratching trajectories. The influence of the feed direction on the amplitude and period of the ripple structure is studied. In addition, the quality of the obtained ripple structure is also analysed.

The electroless Ni-P plating on LY12 substrate was irradiated by a low-energy high-current pulsed electron beam (LEHCEB) to form an intermetallic compound. The microstructure and the morphology of the Ni-P layer after surface treatment were investigated. The results show that the Ni-P layer was melted into low viscosity liquid and quickly moved to a wide variety of shapes and sizes under irradiation of the LEHCEB. X-ray diffraction, energy dispersive spectroscopy and scanning electron microscope were employed to detect intermetallic compounds formed from aluminium–nickel systems including Al₃Ni, AlNi₃ and Al₃Ni₂.

BiOCl/Bi₂S₃ hollow hybrids were synthesised through a mild anion-exchange method from BiOCl microspheres and thiacetamide. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption measurements, ultraviolet–visible–near-infrared diffuse reflectance spectra, photocurrent, and electrochemical impedance spectroscopy (EIS) were employed to study the composition, structure, and properties of the as-synthesised BiOCl/Bi₂S₃ hybrids. Compared to pure Bi₂S₃ and BiOCl products, the as-prepared BiOCl/Bi₂S₃ hollow hybrids exhibited superior capability for photocatalytic reduction of hexavalent chromium under vis light irradiation. The photocurrent and EIS results demonstrated that the low recombination rate of photoinduced electron–hole pairs was contributed to the enhanced photoreduction activity.

To overcome the low mixing efficiency near the vicinity of the wall of the micromixer, a passive micromixer using the recycle flow, with the advantages of simple structure, high reflux rate and high mixing efficiency, has been designed and investigated. In this work, the influence of different structural parameters and fluid properties on the mixing performance was studied by using commercial software ANSYS CFX. The mixing effect of micromixer was also studied by the experiments. A full comparison between the experimental results and simulation results was carried out. The numerical simulation results show that as the jet intensity increases and the viscosity of fluid becomes lower, the reflux rate and mixing efficiency of the micromixer are improved continuously; when Reynolds number (Re) is >15, the maximum reflux rate of the micromixer and the mixing efficiency exceed 35 and 95%. In addition, it was also observed that the simulation results are consistent with the experiments which revealed that the numerical simulation method applied and the results obtained in this work are reliable.

This work aims to investigate the device performance of silicon–germanium (SiGe)/Si carbide (SiC) source/drain (S/D) asymmetric dual-k spacer underlap Fin-field-effect transistor (SiGe/SiC-AsymD-k FinFET) with Si channel for high performance and robust SRAM cell. Strain-induced mobility enhancement due to the Si_1−x Ge _x /Si_1−y C _y S/D leads to a significant drive current enhancement of the proposed device. The introduced asymmetric dual-k spacer at source side offers excellent gate control over the channel. By exploiting asymmetry in current, the authors prove that it is possible to achieve mitigation of read–write conflict in 6T SRAM bit cell. SiGe/SiC-AsymD-k FinFET SRAM offers 8.39% improvement in hold static noise margin, 14.28% in read and 18.06% in write mode over conventional FinFET-based 6T SRAM bit cell. When compared to conventional FinFET 6T SRAM bit cell, the proposed 6T SRAM bit cell shows lesser temperature sensitivity of cell stability.