Two-dimensional (2D) zinc oxide (ZnO) nanostructures have emerged as an attractive approach for constructing high-performance piezoelectric nanogenerators (NGs) because of their high rate of surface area to volume and good mechanical durability for applications in energy conversion devices. However, there has been to date no comprehensive study on piezoelectric characteristics of 2D ZnO nanostructures. In this paper, 2D nanodiscs have been prepared by aqueous solution method on flexible indium tin oxide coated polyethylene terephthalate substrates. Also, the piezoelectric characteristics are statistically demonstrated and analysed on the as-grown 2D ZnO nanodiscs by applying different external force with the finite element method (COMSOL Multiphysics). Besides, the size-dependent simulation analysis of piezopotentials is also conducted for further optimising output performance of NGs based on 2D ZnO nanostructures. Also, the simulation will provide a guideline for designing high-performance piezo-nanodevices.

In this work, a distinctive approach for the suppression of ambipolar behaviour of novel polarity control electrically doped hetero tunnel field effect transistor (TFET) has been reported. For this purpose, a wider band gap material, gallium arsenide phosphide has been employed at drain/channel regions. However, narrow band-gap material, silicon has been used in the source region. This combination of materials leads to a huge reduction in the ambipolar current and significant improvement in ON-state current due to the reduction in the electric field at the drain/channel interface and improvement in tunnelling rate at the source/channel interface, respectively. The proposed device also reduces the drain to source capacitance due to the presence of potential barrier width which leads to improvement in the radiofrequency performance. Therefore, the proposed device is very useful for ultralow power circuit applications. Moreover, polarity gates (PG1 and PG2) have been considered for the formation of n⁺ (drain) and p⁺ (source) regions. Hence, the proposed structure avoids ion implantation, random doping fluctuation, and high thermal budget unlike in the case of conventional TFETs, as the latter is physically doped. All the simulations have been performed using ATLAS software.

The current study reports antioxidant and antifungal activity of green and chemically synthesised zinc oxide nanoparticles in combination with agricultural fungicides carbendazim, mancozeb, and thiram. Nanoparticles were synthesised using previously standardised procedure and characterised, which confirmed particle size of <100 nm. These nanoparticles were then analysed for their antifungal and antioxidant activity. For fractional inhibitory concentration analysis, nanoparticles were combined with fungicides and tested against five fungal phytopathogens, namely Alternaria alternata, Aspergillus niger, Botrytis cinerea, Fusarium oxysporum, and Penicillium expansum. Nanoparticles positively influenced the antifungal potential of all test fungicides and excellent synergism was observed against all tested fungi. Further, the antioxidant activity of the stated nanosuspension was accessed by conducting free radical scavenging assay using 1,1 diphenyl-2-picryl hydrazyl. L- ascorbic acid was used as a standard reference. Radical scavenging improved with increasing concentration of nanoparticles and percent scavenging as high as 87% was observed at 125 µg/mL. Thus, this work reports the synthesis of stable zinc oxide nanosuspension with good antifungal potential and efficient antioxidant activity.

Ultrasonic cavitation in nanofluids improves material removal rate and surface quality. Ultrasonic cavitation in nanofluids was investigated using molecular dynamics simulations. The formation and growth of nanobubbles were promoted, by nanoparticles in water systems. Three distinct impact stages were observed which were caused by the impact of the shock wave, nanojet and nanoparticle. These differed in the system without a nanoparticle. The material removal rate was primarily caused by the nanoparticle hit, a result of the nanobubble collapsing during the third impact. A mechanism of material removal in ultrasonic polishing is discussed at a nanometric level.

A new type of electrode design (jigsaw in shape) is presented for actuating inner electrodes in electrowetting-on-dielectric devices containing large two-dimensional array of electrodes. Electrodes are diagonally connected with one external pin to the voltage supply. Each electrode-pad is made by carving (or cutting) out two triangular sections from the sides and adding two triangular sections on the top and bottom of the traditional square electrode. This modification in electrode shape creates an imbalance of electromechanical force at the three-phase contact line on applying the supply voltage to the actuating electrode. Droplet moves towards either horizontal or vertical directions depending on the direction of the dominant force. The scheme requires a single layer of metal thin film deposition for device fabrication and also reduces the number of external pin connections to the power supply.

Ga₂O₃ is a wide bandgap oxide semiconductor material with the bandgap value only second in magnitude to diamond among known semiconductors. As a wide-bandgap semiconductor, Ga₂O₃ has emerged as a new competitor to silicon carbide and III-nitrides in various applications of ultraviolet optoelectronics and high power electronics. However, almost all the devices are based on the Ga₂O₃ grown by molecular-beam epitaxy or chemical vapour deposition, which is time-consuming and expensive. In this work, the authors report on thin-film transistors based on wide bandgap Ga₂O₃ films grown by aqueous-solution spin-coating method. The morphological, optical and electrical properties of the films and devices are investigated using a range of characterisation techniques, whilst the effects of post-deposition annealing are also investigated. Both as fabricated and post-annealed Ga₂O₃ films are found to be very smooth and exhibit wide energy bandgaps of around 4.8 and 4.9 eV, respectively. Thin-film transistors based on the grown Ga₂O₃ films show n-type conductivity with the maximum electron mobility of 0.1 cm²/Vs.

In this work, we introduce a newly developed passive and frictionless diamagnetic contactless suspension rotor with electrostatic glass motor. A 20 mm diameter disc-shaped rotor comprised of pyrolytic graphite with glass is fabricated. The rotor is diamagnetically and passively levitated by an array of Nd–Fe–B magnets at room temperature without any energy supply. To realise the rotating function, a 700 V high voltage electrostatic glass motor is designed and arranged in the levitation air gap between the rotor and the magnets. To install the stator in this narrow air gap, we fabricated the stator using a flexible printed circuit with 100 μm thickness. The newly developed system is more compact, stable and of high performance. The maximum speed has been improved doubly to 300 rpm in atmosphere. We intend to draw attention to this uncommon levitation and to show that it could be used for micro-mechatronic system.

Cadmium sulphide and titanium dioxide-based junctionless transistor (JLT) has been demonstrated by using simple and low-cost chemical bath deposition method. The morphological and structural study has been performed to speculate the crystallinity and the topography of individual layers of the proposed device. The optimised sputtering conditions lead to the formation of source and drain electrical contacts of the device. The fabricated device successfully functionalised as a p-channel JLT. At the source-to-drain voltage of −50 V, the ON-state drive current and OFF-state leakage current of the fabricated JLT are found to be −6 µA and 1.3 nA, respectively.

In this work, a metal-oxide gas sensor array was fabricated for discriminating several gases at room temperature using ultraviolet (UV) illumination. The sensor array consisted of four interdigitated gold microelectrodes, and titanium dioxide (TiO₂) nanofibres were electrospun on them. The nanofibres were calcined at 550°C for 1 h. Finally, one of these sensors was coated with a thin layer of gold (Au) using DC sputtering method at a thickness of 2 nm. Similarly, the other two sensors were coated with a thin layer of platinum (Pt) and copper (Cu), respectively, and the last one remained uncoated. The nanofibres were characterised by scanning electron microscope, X-ray diffraction, and UV spectroscopy. The examined analytes were methanol, ethanol, NH_3, and acetone, each at seven various concentration levels, including 50, 100, 150, 200, 300, 400, and 500 ppm. Principal component analysis and linear discriminant analysis were used to evaluate the proposed technique. The results demonstrated that the sensor array along with UV illumination could successfully discriminate the analytes at room temperature.‏

A simple, fast, and eco-friendly method for the biosynthesis of gold nanoparticles (AuNPs) using Lilium casa blanca petals as a reducing and protecting agent was reported. The heating time had been shortened to 30 min for biosynthesis of AuNPs, which only took 15 mg Lilium casa blanca petals powder. The biosynthetic AuNPs, which had a uniform particle size distribution, were in spherical with the average size of 5.933 ± 1.158 nm. In addition, the conversion rate of Au³⁺ to Au⁰ was quite high. Through the discussion on the nutrients' concentrations before and after the synthesis, it was found that sugars, alkaloids, flavonoids, and proteins were the reducing and stabilising agents. The biosynthetic AuNPs had good catalytic activity, taking the hydroboration of nitrophenol and methylene blue as examples. Catalytic reduction followed pseudo-first-order kinetics. Moreover, the apparent rate constant was a linear correlation with the concentrations of AuNPs. The normalised rate constant of the proposed AuNPs was higher than other reported AuNPs, which indicated the excellent catalytic activity. All the results foreshowed the wide range of applications of the biosynthetic AuNPs by Lilium casa blanca petals.

Different ratio incorporation of Ag/TiO₂ core–shell nanowires (ATCSN) into TiO₂ as an electron transport layer of perovskite solar cells (PSCs) is studied. This structure can prevent the formation of silver halides between perovskite and silver nanowire. It is found that because of the effective improvement of light absorption and separation of photo-generated electron–hole pairs, the introduction of ATCSN leads to increase of short current density and photoelectric conversion efficiency (PCE) of PSCs. 20 mg incorporation of ATCSN PSCs exhibits the best performance of PCE and a 17.7% increase is achieved compared to the control sample.

For advanced copper (Cu) interconnection applications, this work investigated the influence of impurity particles in the Cu target on the formation of particle defects on the sputtered Cu film. By using a liquid particle counter detection system and X-ray photoelectron spectroscopy, the properties of the impurity particles in the Cu targets were characterised. It is revealed that the impurity particles in the Cu target contain 98.5% carbon, and around 75% impurity particles have a size <1 μm and about 10% ones have a size larger than 2 μm. Subsequently, the correlation between carbon particles in the Cu target and particle defects on the sputtered Cu film is explored. For the carbon particles larger than 0.15 μm in the Cu target, the particle defects formed on the Cu seed layer exhibit a pronounced linear increase as a function of the carbon particle number. However, such a linear relationship becomes unclear for the bigger carbon particles; meanwhile, a small quantity of bigger carbon particles in the Cu target also can generate more particle defects on the Cu seed layer in comparison with smaller carbon particles. Moreover, the formation mechanism of particle defects on the Cu seed layer was also discussed.

Metal-assisted chemical etching process is exploited to realise deep-etched silicon structures. Gold as the noble metal, hydrogen peroxide and hydrofluoric acid solutions are used to achieve deep vertical structures. By controlling the solution concentrations, thickness and morphology of the deposited metal, several hundred micrometre-sized silicon structures can be achieved. This method, upon achieving more controllability and repeatability, can be a good substitute for dry etching, due to its high etch-rate, low-cost materials and non-requirement to complex equipment. In this work, the effect of different etching parameters on the etching process is studied to gain more control over the etching conditions.

Titanium nitride (TiN)-modified hydrophobic-treated carbon paper (CP) was prepared by impregnating CP with polytetrafluoroethylene (PTFE) emulsion containing TiN nanoparticles (NPs). Electrochemical measurements showed that CP witnessed an increase in corrosion resistance and electrical resistivity after treated with 5 wt% PTFE emulsion. Since the sacrifice in electrical conductivity is not beneficial to the application in proton exchange membrane fuel cells (PEMFCs), conductive ceramic NPs – TiN NPs were introduced into the CP to further improve its electrical conductivity. It was found that after adding TiN NPs, the electrical resistivity of CP (immersed in 5 wt% PTFE emulsion containing 8 wt% TiN NPs) decreased to a level (3.8 mΩ cm) similar to that of untreated CP (3.5 mΩ cm), and meanwhile there is a further improvement in corrosion resistance, where the corrosion current density (at 1.4 V) of TiN-modified CP stabilises at the lowest value of 5.50 μA/cm², as compared with 32.8 and 12.7 μA/cm² for raw CP and PTFE-treated CP. According to microstructure characterisation, these improvements could be attributable to the formation of conductive networks and improved PTFE distribution due to the addition of TiN NPs.

A novel silicon (Si) on silicon carbide (SiC) lateral double-diffused metal oxide semiconductor field effect transistor with deep drain region is proposed. Its main idea is transferring the breakdown point and utilising the high critical electric field of SiC material to suppress the curvature effect of the drain, which eventually alleviates the trade-off relationship between breakdown voltage (BV) and specific on-resistance (R _on,sp). Through the TCAD simulation, the results show that the BV is significantly improved from 240 V for conventional Si lateral double-diffused metal oxide semiconductor (LDMOS) to 384 V for the proposed structure with the drift region length of 20 μm, increased by 60%. The figure-of-merit of the conventional Si LDMOS and the Si/SiC LDMOS are 2.04 and 4.26 MW/cm², respectively. It indicates that the proposed structure has better performance than the Si counterpart. The influences of design parameters and interfacial charges on the device performance are also discussed in this work.

Ti⁴⁺ was introduced onto the surface of 3-aminopropyltriethoxysilane (denoted as APTS; a silane coupling agent; commercial name: KH550) by surface-modification technology to afford a precursor of nanoscale cross-linker. The as-obtained precursor of nanoscale cross-linker was further transformed to a Ti-based nanoscale cross-linker (denoted as Ti-NC) by hydrolysis and condensation in association with self-aggregation. The microstructure of the Ti-NC crosslinking guar gum gel was characterised by field emission scanning electron microscopy. Moreover, the effects of the as-prepared Ti-NC on the thermal stability, rheological behaviour, and proppant-carrying ability of guar gum fracturing fluid were investigated with boric acid and TiCl₄ as the controls. Results indicate that the as-prepared Ti-NC has a sphere-like shape and a size of 6–13 nm. In the meantime, the guar gum gel cross-linked by Ti-NC exhibits better thermal stability, rheological behaviour, and proppant-carrying ability than the ones cross-linked by TiCl₄ or boric acid, which indicates that the as-prepared Ti-NC could find promising application in enhancing the oil recovery of the low-permeability reservoir. This is because Ti-NC contributes to enhancing the inter-molecular cross-linking rather than intra-molecular cross-linking of guar gum molecular chains and yielding a tight three-dimensional network structure in the cross-linked guar gum gel.

Brain tumours develop resistance to chemotherapy mainly due to the presence of the blood brain barrier which partially blocks the penetration of drugs into the brain. Poly(butyl cyanoacrylate) nanoparticles have been extensively proposed for delivering drugs into the brain and have shown their ability to cross the blood brain barrier in vitro and in vivo. However, the application of nanoparticles could be limited by their potential side effects. In this study, two glioblastoma cell lines with the poly(butyl cyanoacrylate) nanoparticles were treated at different concentrations. Through MTT assay, the viability of treated cells was quantified. Induction of apoptosis was analysed by flowcytometry as well as quantitative PCR assay for the expression of BCL2 family genes. The results of this study showed that the treatment with poly(butyl cyanoacrylate) nanoparticles induced neither apoptosis nor necrosis in these cells. The quantitative real-time PCR results showed that poly(butyl cyanoacrylate) nanoparticles treatment caused significant changes in the expression of some BCL2 family members. In conclusion, it seems that poly(butyl cyanoacrylate) nanoparticles treatment at non-toxic dose can change the expression of some apoptosis-related genes in glioblastoma cells while has no significant effect on their viability.

The impact of substrate doping on the short-channel effects (SCEs) of bulk-planar junctionless transistor (BPJLT) has been studied. It has been found that increasing substrate doping in bulk region reduces off-state leakage current (I _OFF) and the sub-threshold slope (SS) of the device. To further reduce the SCEs of BPJLT heavily doped δ-layer of thickness 10 nm has been added below the channel. Despite the presence of δ-layer in BPJLT reduces SCEs, the SCE, mainly SS, is still limited by the fundamental limit of 60 mV/decade. Therefore, to reduce SS below 60 mV/decade, negative capacitance (NC) δ-BPJLT has been proposed by adding the layer of ferroelectric material at gate stack. It has been found that in comparison with conventional BPJLT and δ-BPJLT, the insertion of ferroelectric layer in NC-δ-BPJLT not only reduces the I _OFF and the SS but also improves I _ON/I _OFF ratio of the device. Thus, embedding heavily doped δ-layer in the bulk region and the ferroelectric layer at the gate stack of BPJLT makes it a promising device for low-power applications.

In this work, folate-phytosterol-carboxymethyl cellulose nanoparticles (FPCMC NPs) derived from plant material were fabricated and investigated as carrier of hydrophobic anticancer drugs. Firstly, hydrophobic phytosterol was grafted onto the framework of water-soluble carboxymethyl cellulose. Then folate, as tumor-targeting ligand, was coupled to the phytosterol-carboxymethyl cellulose to become self-assembled FPCMC NPs. The physicochemical properties of the fabricated FPCMC NPs were characterized. Doxorubicin (DOX) was selected as model anticancer drug that was entrapped in prepared FPCMC NPs with satisfactory loading content (7%) and loading efficiency (71.2%). The in vitro drug release test showed that the release amount of DOX from drug-loaded FPCMC NPs at pH 5.3 was much higher than that at pH 6.5 or pH 7.4. The research results indicated that the fabricated FPCMC NPs had the potential as nanocarrier of hydrophobic anticancer drugs for further experimental study.

The design of integrated components using hybrid plasmonics is attracting a widespread interest in the recent years. This work proposes a consistent approach to design Bragg gratings employing the concept of graded profile in a planar hybrid metal–insulator–metal plasmonic waveguide. A comparative study of various width modulations such as triangular, parabolic and rectangular profiles is presented. The most striking observation is that Bragg gratings with parabolic profile offer best performance in terms of compact track length (3.48 μm), wide stopband (168 nm) and good transmission characteristics with fewer side lobes. Additionally, a nanocavity analysis is performed by introducing a defect length of 140 nm in the Bragg grating structure with parabolic profile. A peak transmission of 89% is observed at the resonance wavelength of 1550 nm.