Microfluidics has been widely used in the biological, chemical and recently in the energy field. In the past decade, microfluidics has experienced tremendous growth in academia; researchers in various fields have been using microfluidics as a powerful tool for the enchantments of their research. However, the fabrication technologies of microfluidics are sourced from microelectromechanical systems and integrated circuit industry, which the fabrication process is costly and time-consuming, with the need of highly sophisticated instruments and experienced technical personnel to conduct fabrication process in the cleanroom environment. To lower the technical barriers for microfluidics, more and more researchers in different fields have invented various low-cost fabrication methods for microfluidics using polymers or paper materials. Comparing to the conventional microfabrication process conducted in the cleanroom, the low-cost fabrication methods are more flexible, with significant reduction in material cost, fabrication cost and processing time. This review is trying to introduce the most recent developments in low-cost microfluidics, from the aspects of materials, microfabrication and bonding technologies. The comparison and scope of application for different low-cost fabrication technologies for microfluidics were also provided in this review.

The Ni–W–S nanoparticles (NPs) were synthesised on Ti mesh through the typical hydrothermal method. The obtained Ti/Ni–W–S was characterised on morphology, composition and electrocatalytic property. It showed good electrocatalytic performance towards glucose oxidation in strong alkali electrolyte, exhibiting the potential application in the field of fuel cell. The excellent electrocatalytic activity of Ni–W–S NPs, the favourable electron transfer between electrode and catalysts, as well as the high conductivity of Ti contributed to its final catalytic performance of Ti/Ni–W–S.

In this work, a ferroelectric dielectric based TiN-GAA MOSFET with metal work-function variations (WFVs) has been proposed. The proposed model exhibits higher I _on/I _off ratio and lower subthreshold swing (58 mV/decade) as compared to conventional GAA MOSFET as a result of an amalgam of both gate all around (GAA) geometry and ferroelectric effect. The investigation is further extended to different technology nodes with WFV. The WFV induced threshold voltage is considered to be a function of the ratio of average grain size to grain area concept. The model exhibits a higher probability of threshold matching as compared to previously published results and the superiority is reflected in the Pelgrom plot. Thus the model can provide insight to counter the challenges created by WFV.

Highly uniform columnar-shaped CeO₂ was successfully prepared in large quantities by calcining a precursor, which was prepared by a simple hydrothermal method. The structure and morphology of the precursor and the columnar CeO₂ were characterised by X-ray diffraction and scanning electron microscopy. The columnar CeO₂ was fixed on a glassy carbon electrode to obtain a columnar CeO₂ sensor for detection of phenol. The anodic peak current was proportional to the phenol concentration in the range of 0.005–0.225 mmol l⁻¹ (R = 0.995) and 0.225–1.125 mmol l⁻¹ (R = 0.998) with the detection limit of 0.9 μmol l⁻¹. This electrochemical method has the advantages of simplicity and ease of fabrication, rapid detection, low cost of the apparatus and wide dynamic ranges.

Seeking for the porous carbon with suitable structure and morphology has been a key to improve the lithium storage performance of carbon/selenium composite. In this work, the hierarchical porous N,O Co-doped carbon has been prepared by an initial hydrothermal carbonisation and subsequent activation route using the chitosan as raw material. The carbon obtained at 600°C possessing primary micropores and surface macropores presents high specific surface area (809. 3 m² g⁻¹) and low porous size, and the selenium with amorphous structure is uniformly encapsulated into the micropores of this carbon to form carbon/selenium composite. As the cathode materials of lithium ion battery, this composite delivers a discharge capacity of 446.9 mAh g⁻¹ at rate of 0.24 C after 100 cycles. At a high rate of 4.8 C, this composite still shows a stable discharge capacity of 342.8 mAh g⁻¹. These results suggest that this composite may be promising for practical applications for lithium-selenium battery.

Sintered at different sintering temperatures, Eu²⁺ doped BaAl₂Si₂O₈ phosphors were synthesised through one-step calcination process of precursors prepared by chemical coprecipitation method. Thermal gravity-differential thermal analysis was used to investigate the initial temperature of phase transition and the optimal sintering temperature of the sample synthesis. The X-ray diffraction patterns confirmed that the sample calcined at 1200°C possessed a single hexagonal phase of BaAl₂Si₂O₈. Although a little BaAl₂Si₂O₈ phase had been produced, BaAl₂O₄ phase was dominant in the sample calcined at 1000°C. The morphology of the sample observed by scanning electron microscope showed smooth surfaces and nearly spherical shapes at higher sintering temperature. The emission spectrum of the sample calcined at 1000°C was separated into three Gaussians with the maximum at about 455, 501 and 540 nm, due to the 4f⁷→4f⁶5d transitions of Eu²⁺ ions occupying the Ba site of BaAl₂Si₂O₈ and the Ba(1) and Ba(2) site of BaAl₂O₄, respectively. With the increase of sintering temperature, BaAl₂Si₂O₈:Eu²⁺ phosphor exhibited a blue broad emission band peaking at 455 nm with full width at half maximum about 90 nm under near-ultraviolet excitation at ∼400 nm, and its emission intensity increased considerably due to the improved crystalline and homogeneous distribution of Eu²⁺ ions.

Flower-like CeO₂/bismuth oxychloride (BiOCl) heterostructures were successfully prepared by a simple two-step solvothermal/hydrothermal method. The prepared materials were characterised via powder X-ray diffraction measurements, scanning electron microscopy, energy dispersive spectrometry, transmission electron microscopy and ultraviolet–vis diffuse reflectance spectra. Photocatalytic activities of the materials in the degradation of rhodamine B (RhB) were studied. The results showed that all of the materials were successfully prepared. In particular, the BiOCl looks like a cluster of chestnut balls and the CeO₂/BiOCl composite showing a flower-like morphology. Compared with the pure BiOCl or CeO₂, the CeO₂/BiOCl composite showed higher photocatalytic activity for degradation of RhB in aqueous solution under ultraviolet light irradiation.

This work presents the effect of ferroelectric thickness variation on properties (negative capacitance stabilisation, voltage amplification and capacitance enhancement) of ferroelectric–dielectric (FE–DE) heterostructure. For a better understanding of heterostructure, the study has analysed isolated ferroelectric capacitor first. Results clearly indicate the unstable nature of negative capacitance in ferroelectric capacitor. This negative capacitance can be stabilised by adding a dielectric capacitor in series with ferroelectric capacitor. Dielectric capacitor not only stabilises the negative capacitance state but is also responsible for the increase in capacitance of heterostructure. Afterwards dynamic response of FE–DE hetrostructure is studied. It is observed that thickness has strong dependence on ferroelectric parameters. With the increase in ferroelectric thickness, ferroelectric capacitance decreases and hence leads to voltage amplification. However, ferroelectric thickness should not be increased beyond critical thickness, as beyond critical thickness voltage amplification cannot be achieved without hysteresis.

Manufacture of microbe-resistant clothing is the need of the hour especially in microbe sensitive environments such as hospitals. Silica nanoparticles (SiO₂) were prepared from xerogels synthesised from cotton pods. In the present work, a novel fabric was prepared using SiO₂, non-woven cotton fabrics and polyethylene glycol (PEG). Different types of fabrics were prepared by incorporating different concentrations of the SiO₂. Among the fabrics, 3% exhibited significant antimicrobial activity. The smooth surface morphologies of the fabric were proved by scanning electron microscopy. Fourier transform infrared spectroscopy spectrum of fabric represented the characteristic bands of all the components, i.e. SiO₂, PEG and cotton fibre. A potential fabric, which possesses microbe-resistant property, and hence they could be of promising use in medical cloths production.

The traditional capillary mixing using a closed channel and a mixing unit without the delay valve encounters problems of backflow and clogging. Here, the polydimethylsiloxane (PDMS) mixing channel with the facile delay valve and open surface design has been demonstrated using the two-step moulding for long-term-hydrophilic capillary-pumping. The triggering of delay valve before the mixing unit is controlled by the specific channel height calculated using capillary theory. It can eliminate the problems of backflow, clogging and bubble defect. Also, the channel height in an open channel is reduced to 150 µm compared to the close one of 250 µm by numerical analysis. The CO₂-laser-ablated polymethylmethacrylate (PMMA) mother mould can avoid the complicated fabrication process using photolithography and SU8 mould. Using the unique two-step PDMS moulding method can greatly diminish the defect from the laser-ablated PMMA mould for a smoother surface. The naturally hydrophobic PDMS is modified using the polyethylene glycol and O₂ plasma treatment to solve the sticking problem and prolong the hydrophilicity up to 164 h and more which is tested in the contact angle aging measurement.

Graphene materials especially single-layer graphene have been identified as a new generation of nanomaterials having various potential applications in material industries. However, the synthesis procedure of single-layer graphene to improve its quality, size and amount has been still under research for commercial applications. The graphene oxide (GO) is synthesised from graphite by Hummer's spontaneous approach which is the most suitable reaction for a large-scale production. For the single-layer graphene, in this work, GO was exfoliated by using a ball milling in an inert atmosphere. Owing to using ball milling as intermediate treatment degreased oxygen functional groups and number of layers, it facilitates to synthesise graphene. Sodium borohydride (NaBH₄) and hydroquinone were used as a reductant for the chemical conversion of the exfoliated GO to graphene. The results showed that due to the strong reduction feature, both reducing agents can be applied in the graphene production. As a preferred reductant, hydroquinone can be successfully applied for the synthesis of the single-layer graphene compared to NaBH₄. The obtained graphene particles by two different chemicals were characterised by various analytical techniques. The big difference in the structure of GO and graphene was observed in transmission electron microscope analysis.

Porous structure materials indicate brilliant distribution and great absorption ability, that suggesting the potential application of aerogel state graphene based materials. Aerogel intermedium assisted method was developed and optimised to prepare bendable electrode. Hydrothermal schedule was utilised suggesting potential application at low cost and large-scale factory print issues, rather than consuming high money cost and long labour time. Nickel sulphide has been anchored onto the graphene aerogels via one-pot hydrothermal method. The membrane electrode was made with the carbon ink and aerogel intermedium on the Poly(ethylene terephthalate) (PET) plate. The bendable electrode was fabricated with intermedium and commercial carbon ink, and indicates good performance and economic consumption. The complex membrane capacitor shows the much more brilliant performance than the pure carbon membrane capacitor, with specific capacitance (31.40 mF/cm² at 4 mV/s and 17.74 mF/cm² at 2 mA/cm²).

This work proposes a microfluidic structure utilising its damping motion for energy harvesting based on a microfabricated electret silicon oxide (SiO₂). When the device was subjected to an instantaneous acceleration, the power was generated due to the variable shape of the microfluidic on the electret SiO₂ film. The damped wave phenomena came from the variable shape of microfluidic which oscillated back and forth due to inertial forces. With a larger acceleration on the device, the peak value of a short-circuit current (I _sc) and an open-circuit voltage (V _oc) were increasing as a function of linear equation and quadratic equation, respectively. The microfluidic energy harvester reached up to 3 nA of I _sc and 0.18 V of V _oc with an acceleration 4 m/s², respectively. Moreover, with a microdrop with dimension 15 mm³ on the inorganic SiO₂ film, the work demonstrated that the device can obtain V _oc of 0.3 V and I _sc of 3 nA with a sliding angle ∼30°, which showed further applications for an angle sensing.

In the current study, the successful application of polypyrrole-Fe₃O₄ nanoparticles (NPs) was investigated as a suitable sorbent in the magnetic-dispersive solid phase extraction mode to the preconcentration and determination of atorvastatin (AT) in human serum by high-performance liquid chromatography-ultraviolet detection. Iron oxide NPs were prepared by co-precipitation method and the polypyrrole compound was used to modify their surface. The structure and NP size of Fe₃O₄@PPy NPs were characterised by Fourier-transform infrared technique and scanning electron microscopy. Some factors affecting the extraction efficiency, including the pH value, amount of sorbent, extraction time, elution type and its volume and desorption time were optimised. Under the optimum conditions, magnetic NPs extraction of standard solution of AT showed a linear calibration curve in the range of 0.1–1000 μg l⁻¹ with R ² = 0.9962. The method was sensitive, with a low limit of detection (0.10 μg l⁻¹) and quantification (0.38 μg l⁻¹). The relative standard deviation of five extractions at the concentration level of 0.1 μg l⁻¹ was 4.2. Good recoveries (92.00–98.10%) with low relative standard deviations (6.0–2.4%) indicated that the matrices do not significantly affect the extraction process. Finally, the proposed method was successfully used to measure AT in human serum samples.

In this work, a new nanocomposite as silver nanoparticles (AgNPs)@ porous silicon (PSi) was synthesised through a simple galvanic displacement reaction between silver ions and silicon in the presence of hydrofluoric acid. The as-prepared nanocomposites were characterised via field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and electrochemical methods. Since the nanocomposite showed a greatly enhanced electrocatalytic activity towards the glucose oxidation in alkaline solution, Ag nanoparticles supported on PSi flour were used as a performance modifier in the construction of a new amperometric glucose screen-printed carbon electrode. The enzymatic free glucose sensor based on AgNPs@PSi exhibited a wide linear dynamic range of 1 × 10⁻⁶–45.7 × 10⁻³ M, with a detection limit of 6 × 10⁻⁷ M at a signal-to-noise ratio of 3, and fast response (<3 s). Also, the response of the proposed sensor was selective towards glucose in the presence of common species such as ascorbic acid, dopamine, uric acid and Cl⁻ ions. Finally, the sensor was successfully applied to determine glucose in human serum samples.

Vertically aligned InGaN/GaN nanorod arrays with multiple quantum wells (MQWs) was prepared via inductively coupled plasma (ICP) followed by a further anisotropic wet etching method. It was demonstrated that the sizes of nanorods could be easily regulated in the ranges of 330–1090 nm by simply controlling the ICP etch parameters. The morphology characterisation results indicated that these nanorods are of straight and smooth appearance, and the length of nanorods is about 4 μm. Ultraviolet (UV) detectors based on nanorods arrays with different diameters were fabricated, which exhibited fast response/recovery speed and good response. The UV detecting performance was getting better with the decrease of nanorods diameter, which may be caused by the suppression of the dark current. This work provides an efficient route for fabricating the large-scale vertical aligned MQWs nanorods array and developing their fascinating applications.

γ-Bi₂O₃ powders were prepared from [Bi(NO₃)₃·5H₂O] and NaOH through low-temperature liquid phase method at <90°C. This process featured low cost, simplicity and a normal pressure. Bismuth oxides were synthesised in large quantities in water systems. Morphology, structure and optical properties were characterised by X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and ultraviolet visible absorption spectrophotometry (UV–Vis). The SEM indicated that tetrahedral Bi₂O₃ with the edge length of 1–5 μm was formed. The FTIR spectra show a chemical bond of Bi–O existed. Bi₂O₃ presents the photo absorption properties from UV light region to visible light and the band gap of the Bi₂O₃ is 3.0 eV.

This study presents a quadruple core/shell nanostructure of Ag@SiO₂@Eu³⁺(tta)₃Phen@Protein with both excellent fluorescent property and blood compatibility. Surface-plasma resonance (SPR) was utilised to enhance the fluorescence of europium (Eu³⁺) complexes. In this situation, the fluorescence of Eu³⁺(tta)₃Phen in the triple Ag@SiO₂@Eu³⁺(tta)₃Phen nanostructure is greatly enhanced. To increase the biocompatibility in blood, lysozyme was used to modify the surface of the above triple nanostructure to get the quadruple nanostructure of Ag@SiO₂@Eu³⁺(tta)₃Phen@lysozyme. Then, through the clinical anti-coagulation tests in human blood, the blood compatibility of Ag@SiO₂@Eu³⁺(tta)₃Phen@lysozyme is largely improved comparing with the triple nanostructure of Ag@SiO₂@Eu³⁺(tta)₃Phen, and the values of PT-S, APTT-S, TT-S, and AT-III of quadruple nanostructure blood sample with the modification of protein have the high correlation coefficients, 0.993–0.994, which means that the quadruple nanostructure of Ag@SiO₂@Eu³⁺(tta)₃Phen@lysozyme is close to the anti-coagulation property of physiological saline state (0.9% NaCl aqueous solution). Thus, this work provides two key properties of the quadruple nanostructure of Ag@SiO₂@Eu³⁺(tta)₃Phen@lysozyme: the excellent fluorescence and the outstanding blood compatibility. This nanomaterial can be applied to bio-imaging and bio-sensing in blood.

Carbon microfibres (CMFs) were synthesised on SiO₂ particles by catalytic chemical vapour deposition at 1200°C using ethanol as carbon precursor, iron nitrate as the catalyst precursor, and nitrogen as a carrier gas. The structure and morphology of the products were characterised by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy. CMFs obtained after a deposition time of 5 h have a diameter of 5–10 μm and a length of a few hundred micrometres. In the deposition process, Fe–Si–O–C droplets were first formed on the surface of SiO₂ particles, and then carbon fibres grew as a result of the catalysis of the droplets. Carbon fibres have the higher graphitic structures when the deposition process is conducted at 1200°C.

Three-dimensional (3D) integration is an emerging technology that aims to achieve efficient packaging of the multifunctional silicon (Si) die within a single chip package. This system in package approach achieves connectivity between the individual Si die using through Si via (TSV) technology. Coaxial TSVs have emerged as the preferred 3D interconnect for high-frequency packaging applications due to their superior high-frequency electrical characteristics. The interconnect utilises a copper shield to prevent noise and unwanted signal coupling to occur within the Si substrate. However, a potential disadvantage of 3D integration is the large transistor keep-out-zones (KOZs) required to prevent transistor variability caused by thermally induced stress due to the copper-based TSVs in the Si substrate. Currently, only analytical models exist that predict KOZs for various coaxial TSV configurations and determining the precise KOZ is critical to minimise interconnect footprint that results in increased costs due to reductions in Si die area for integrated circuit designers. For the first time, the work has characterised the thermomechanical behaviour of fabricated coaxial TSVs utilising the microRaman spectroscopy technique to define transistor KOZ for both analogue and digital circuital applications.

Transparent and flexible force sensor provides potential applications in a lot of area such as human wearable sensor, robotic sensor and underwater equipment. Here the work presents a zig-zag patterned hydrogel-based force sensor. Slow-gelling alginate hydrogel, self-designed microextrusion 3D printer and polydimethylsiloxane (PDMS) were adapted for the sensor fabrication. A slow-gelling hydrogel printing ink was prepared and printed onto the treated PDMS layer with a computer-aided designed zig-zag pattern. The line width and resistance of the printed hydrogel were precisely controlled by the self-designed microextrusion 3D printer. To stabilise the water content, a sandwich structure was adopted and two PDMS cover layers were fabricated to seal the hydrogel sensor. Theoretical analysis was performed and it is shown that the change rate of resistance was linear related to the force, and this analysis was proved by experiment. Experiments also show that the sensor was flexible and transparent. The zig-zag patterned hydrogel also and the PDMS layers provided stable water content and recording.

Silica fume was thermally treated to 700–1100°C in air to transform it into crystals and cause it to reach the metastable cristobalite state. The phase transition behaviour of the silica fume crystallisation process and the main factors influencing the crystallisation behaviour were investigated via thermogravimetry differential thermal analysis, X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The results show that when the treatment temperature reaches 800°C, the silica fume undergoes a displacive phase transformation and begins to nucleate. At 1100°C, the silica fume fully converts to cristobalite. Alkali metal impurity compounds in the silica fume promote the phase transformation of silica fume.

The need to overcome the shortcomings of conventional tunnel field-effect transistor (TFET) has driven many to come up with advanced TFET innovations. This Letter presents a comparative analysis of new techniques to enhance DC/radio-frequency (RF) performance of dopingless TFETs. In this regard, two advanced structures have been compared along with conventional electrically doped TFET. The devices – electrically doped TFET, low work-function strip electrically doped TFET and low work-function live strip electrically doped TFET are investigated in terms of DC, RF and linearity. This Letter focuses on electrical doping on dopingless substrate to reduce random dopant fluctuations and fabrication complications. The comparative analysis illustrates the importance of low work-function live strip (LWLS) over low work-function strip (LWS). In addition, an optimisation of length and position of LWS and LWLS is also investigated for providing fabrication ease.

Nanotechnology is an interesting way to produce and deal with fascinating features of materials. Metal nanoparticles offer a vast spectrum of potential applications in medicine and pharmaceutical sciences due to advances in nanotechnology research. This study was aimed to evaluate the anticancer properties of gold–silver (Au–Ag) alloy nanoparticles, which were synthesised using a green method by Galega officinalis ethanolic extract. The antitumour activity of biosynthesised nanoparticles has been assessed in vitro using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay on DU-145 and HT-29, prostate and colon cell lines, respectively. The Au–Ag alloy nanoparticles activity to inhibit the growth of cancer cell lines was recorded in terms of decrease in viable cell count in comparison with the control value. The spherical Au–Ag alloy nanoparticles with average size of 100 nm diameter were synthesised. The growth inhibition of the human prostate (DU-145) and colon carcinoma cell line (HT-29) has been found to be dose dependent. The calculated IC50 for the DU-145 cell line was 95.78 μg/ml after 24 h and for the HT-29 cell line was 70.66 µg/ml after 48 h. The results of this study suggest that Au–Ag alloy nanoparticles could be as an active substance against tumour cell lines and may be a beneficial treatment for cancer.

Rapid tunnelling junction formation is a much crucial issue with conventional sub-nanometre tunnel field-effect transistor (TFET) to obtain improved electrostatics characteristics. This task becomes more problematic and complicated for dopingless TFET as a result of wide tunnelling barrier at channel/source junction. In this regard, a new approach has been employed by implanting the metal angle (MA) inside the dielectric layer near channel/source joint to obtain enhanced electrical behaviour of the proposed structure. Employment of MA of small work-function increases electron density at channel/source interface to have improved electron tunnelling rate. Work-function optimisation of MA on RF/DC parameters is analysed in device optimisation part of this work. Simultaneously length optimisation of MA is also presented in the device optimisation section to ease the complex fabrication steps. In addition to these, circuit level performance of proposed and conventional structures is also analysed in this study.

In order to meet the requirement of impact modifier, the agglomerated butadiene-styrene rubber (a-SBR) latexes were first prepared by bubbling CO₂ into original butadiene-styrene rubber latex with the diameter about 100 nm, and then the poly(methyl methacrylate-butadiene-styrene) latexes (a-MBS) with a wide particle size distribution were fabricated via seeded emulsion copolymerisation of styrene and methyl methacrylate onto the a-SBR seeds. It was found that the pH value of the system decreased slowly with the time of CO₂ bubbling, while a-SBR particles were not enlarged until the pH value reduced to about 8. In particular, when the pH value decreased to around 7, the size of a-SBR particles enlarged dramatically and the agglomerated system should be adjusted immediately to alkaline condition with NaOH aqueous solution. Transmission electron microscopy observation indicated that the a-MBS particles with a wide size distribution were successfully prepared. Moreover, both the shell thickness and grafting efficiency of the MBS particles decreased gradually with the increasing SBR particle size, while the rubber volume fraction of MBS particles increased. The whole process of agglomeration and grafting copolymerisation is mild, efficient and has great potential in the industrial application.

The green synthesis of the platinum (Pt) nanocomposite was achieved using a natural biopolymer gum kondagogu (GK), a widely preferred reducing agent because of its biocompatible and biodegradable nature. The synthesised GK Pt nanoparticle (GKPtNP) were characterised by using different analytical techniques such as ultraviolet–visible spectrophotometer, transmission electron microscope, X-ray diffraction, and inductively coupled plasma mass spectroscopy (ICP-MS). The objective of the present work was to evaluate the anti-fungal activity of GKPtNP against two strains Aspergillus parasiticus and Aspergillus flavus for the first time. The results revealed that GKPtNP-treated fungal cell suspensions showed the minimum inhibitory concentration of 10 μg ml⁻¹ for both the strains and exhibited IC₅₀ values as 37.2 and 29.4 μg ml⁻¹, against A. parasiticus and A. flavus. The mechanism of action of Pt nanocomposite on fungi outer membrane and generation of reactive oxygen species (ROS) was elucidated. It was observed that the interaction of GKPtNP caused destabilisation of fungal outer membrane signifying elevated levels of ROS leading to oxidative stress. In conclusion, the Pt nanocomposite materials acted as a fungicidal agent against A. parasiticus and A. flavus and give a significant scope in various biomedical applications.

Perovskite ferroelectric thin films have attracted much attention for the potential applications in modern microelectronics, micro-electro-mechanical systems, and information storage. Computer simulation is helpful for optimising the process parameters and manufacturing high-performance ferroelectric thin films. Herein the work presents a kinetic Monte Carlo method for simulating the submonolayer growth of homoepitaxial SrTiO₃ (STO) thin films, and investigate the effects of substrate temperature, incident kinetic energy of adatoms, and deposition rate on the growth of STO thin films. The results show that with the increase of the substrate temperature, and the incident kinetic energy, or the decrease of the deposition rate, the density of islands decreases, and the bonding ratio increases. This study provides an understanding of submonolayer STO thin films growth at atomic scale.

Efforts have been made to investigate the role of adding carbon nanotubes (CNTs) as the sound energy decaying fillers on the physical and mechanical properties of polyurethane (PU) foam and thus to correlate them with its directly measured sound absorption coefficient. For this aim, the microstructures of PU/CNT nanocomposite foams were investigated and analysed through field emission scanning electron microscopy. Owing to the different microstructures of the samples, large differences were observed in their morphological and physical properties such as density, porosity, pore diameter, closed pore content and thus on their acoustic damping performance.

Un-doped and Ba-doped ZnO nanoparticles (Zn_{1− x} Ba _x O 0 wt% ≤ x ≤4 wt%) were prepared by the sol–gel method and annealed at 500°C for 4 h under air atmosphere. Several techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy and scanning electron microscopy were used to characterise the as-prepared samples. The samples exhibited hexagonal ZnO lattice structure and a secondary phase of BaO is evolved for the sample with x = 0.02 and 0.04. The calculated average crystalline size decreases from 38.27 to 33.74 nm for x = 0 to 0.02 then reaches 39.93 nm for x = 0.04 which is confirmed by TEM. The change in micro-strain and a small shift in XRD peaks reveal the substitution of Ba²⁺ ions into the ZnO lattice. Additionally, using Ba-doped ZnO powders via this sol–gel method after sintering in air at 1150°C for 2 h, the varistor possesses good electrical characteristics, with present nonlinear coefficient of ∼24.43 and breakdown voltage of ∼2487.27 V/cm.