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This paper investigates the reliability of a dual metal gate-hetero-material junctionless tunnel FET (DMG-HJLTFET), by using a novel combination of III–V compound semiconducting materials, $$\mathrm{InAs}$$ (lower bandgap) in the source region and $$\mathrm{GaAs}$$ (higher bandgap) in the channel and drain regions. We applied bandgap engineering and dual material gate engineering to improve the linearity metrics and distortion parameters by optimizing an appropriate lower work function tunnel gate toward the source and higher work function supplementary gate toward the drain and compared all the results with SMG (single metal gate)-HJLTFET and Si-JLTFET. The DMG-HJLTFET showed marked improvements in terms of ION, ION/IOFF, SS, $${g}_{\mathrm{m}}$$ , $${g}_{\mathrm{m}3}$$ , VIP2, VIP3, and 1-dB compression point. The input power, IIP3 of DMG-HJLTFET, is 158% greater than SMG-HJLTFET and is 154.7% greater than Si-JLTFET. The distortion power, IMD3 of DMG-HJLTFET, is 171.8% and 20.5% lower than SMG-HJLTFET and Si-JLTFET, respectively, thereby making it suitable for low-power distortion-free wireless communication systems.

With the development of science and technology, the research on magnetic materials is particularly important. In particular, the application of nanomagnetic materials in computer chips, magnetic recording, and biomedical fields has high research value. In this paper, Ni–Cu–Co ferrite nanomagnetic materials doped with rare earth (RE = Y3+, Sm3+, La3+ and Yb3+) ions were prepared by sol–gel auto-combustion method. The spinel structure of the sample was analyzed by X-ray diffraction (XRD), and the average crystallite size of the doped rare earth ions was calculated by the half width of (311) peak. The samples were further characterized by Fourier-transform infrared spectroscopy (FT-IR). Two characteristic peaks are at the wave number of 603 cm−1 and 391 cm−1, respectively. The morphology of the nanomagnetic grains was observed by scanning electron microscopy (SEM), and it was found that the nanomagnetic grains of the samples were all spherical or quasi spherical structure with water chestnut. Transmission electron microscopy (TEM) was used to observe the pure samples and Y3+ ion-doped samples. Through EDS analysis, it is found that the chemical composition of the sample is Ni, Cu, Co, Fe, O, Y, Sm, La, and Yb. Through vibration sample magnetometer (VSM) analysis, the samples of Ni–Cu–Co ferrite doped with different RE3+ ions have the characteristics of ferromagnetism.

The widespread application of white light-emitting diodes makes us surrounding by plenty of blue-rich light, promoting the development of blue-light-blocking filters because blue light between 415 and 455 nm wavelength can cause light damage to the retina cells. While longer wavelength blue light is also essential to trigger physiological responses, which puts forward higher requirements for the precise blue-light-blocking ability of the filters. In this paper, CdS quantum dot (QD) with strong absorption in the blue region was synthesized and its size was regulated by extended reaction time. Polymerizable molecule was chemically grafted on CdS surface and then copolymerized with methyl methacrylate (MMA) monomer for transparent films with a narrow absorption transition band (wavelength span from 0.05 to 0.8 Tmax) about 20 nm and tunable cut-off wavelength at 0.05 Tmax from 436.9 to 447.8 nm due to quantum size effect of CdS QD. This provides a possibility for more accurate adjustment of the blue-light-blocking performance, minimizing the harmful visual damage of short-wave blue light and preserving the beneficial physiological effects of long-wave blue light.

In the present study, the inclusion of 6H foreign polytype was seen during the initial growth of 4H polytype silicon carbide single crystal by PVT technique. The foreign polytype inclusion was gradually diminished with growth time; the mechanism is described in the present paper. In order to study the defects, the SiC specimen was wet etched using KOH solution at higher temperature and it was found that the foreign polytype inclusions i.e. 6H polytype introduced high density of defects at the polytype boundary. The defect distribution in different regions viz. 6H polytype foreign inclusion, 4H polytype region and polytype boundary were found to be different. It is interesting to note that the threading screw dislocation was not seen in 6H-polytype inclusion region.

In this paper, using first-principles calculations based on density function theory, we systematically investigate the electronic structures and properties of the bilayer g-SiC3 systems. Among all three bilayer g-SiC3 systems considered here, the AA stacking (all C/Si atoms in upper SiC3 layer lie above the C/Si atoms in lower SiC3 layer) with an indirect bandgap is most stable. The bandgap calculated by PBE and HSE06 are 1.380 eV and 1.959 eV, respectively. Our results revealed that the bandgap could be modulated effectively by applying in-plane biaxial compressing/stretching or vertical strain along the ‘z’ axis. When the tensile stress reaches 3%, the bilayer AA g-SiC3 system changes from semiconductor to semimetal. Moreover, under vertical stretching of ∆d = 0.4 A (d = 2.83 A), the bilayer AA g-SiC3 turns from an indirect bandgap semiconductor to a direct bandgap semiconductor, which is attractive for realizing the nanoscale multi-functional device applications. Our results provide a theoretical understanding for future SiC3-based electronic nanodevices with controlled bandgaps.

This paper studies in detail the effect of fuel/oxidant (citric acid/nitrate) ratio on the crystal structure and electrochemical performance of CuFe2O4 prepared by combustion method. The electrochemical tests results show that when the ratio of citric acid to nitrate is 0.6, CuFe2O4 exhibits the best electrochemical performance. After 80 cycles, the discharge specific capacity can still reach 336.2 mAh g−1. In the rate test, after 10 cycles at 2000 mA g−1, the average specific capacity can still maintain at 404.5 mAh g−1. Through the analysis of chemical properties and electrochemical properties, it is believed that the superior performance may stem from the porous structure, appropriate crystallinity, and the suitable grain size induced by the suitable citric acid–nitrate molar ratio.

This paper designs a novel structure to increase the modulation bandwidth of GaN-based light-emitting diode. The structure mainly includes the periodic Ag nanopillar arrays and diamond arrays. The periodic Ag nanopillar arrays are used to induce surface plasmons, and surface plasmons can strongly couple with quantum wells to increase the carrier concentration of light-emitting diodes, so as to increase the recombination opportunities between electrons and holes, thus reducing the carrier recombination lifetime. The diamond arrays are used to improve the heat dissipation performance of the device, so as to reduce the carrier recombination lifetime by increasing the injection current density of the light-emitting diode. The COMSOL software is used to simulate the designed structure, and the average electric field mode and temperature distribution are obtained. The high modulation bandwidth light-emitting diode provides an advantage for increasing the transmission rate of the visible light communication system.

The performance of a solar photovoltaic module can be improved with aid to predictive, corrective and preventive maintenance procedures. Most of the solar modules installed in the roof top are under non-maintenance state. For the locations like dusty environments and deserts, the dust accumulation will be more. Hence, it is the major requirement to clean the PV modules which are much costlier to do in regular basis. In this paper, an anti-reflective coating (hydrophilic) is used to deteriorate the losses due to reflectance in a solar PV module and thereby enhancing its efficiency. In addition to it, easy-to-clean coating (super hydrophilic) is used to improve the dust cleaning effectiveness in a solar PV module. The material employed for anti-reflective coating is MgF2 and for easy-to-clean coating is SiO2. Two polycrystalline solar PV modules of 10 Wp capacity with model ADT12AN are connected to similar kind of optimized load of 40 Ω in a field condition. American Standard Testing Methodology (ASTM: E948) is used for standard test measurements. Based on the characteristics of different coating techniques, the optimized coating performance is considered. One module coated with anti-reflective and easy-to-clean coatings is considered for the analysis. The comparative analysis between the modules is undertaken with LABView software. An extensive analysis for module performance validation with experimental setup is carried out to show the effectiveness of the proposed system. From the results, it can be clearly observed that a 2% rise in the overall power performance using anti-reflective coating is achieved. This can lead to an increase in yearly energy output of the solar plant.

This paper presents corn husk-based microwave absorber along with the enhancement of microwave absorption performance by adding a different percentage of charcoal in the frequency range of 1–20 GHz. The open-ended coaxial probe method is used to measure the S11 parameter, and also dielectric properties of the samples. The computer simulation technology microwave studio (CST MWS) is used to design the proposed microwave absorber. The result shows that the sample with the utmost charcoal content (4.44 wt%) poses the best return loss value of − 50.2696 dB at 19.221 GHz frequency.

Bi12MO20 (M: Si, Ge, Ti, etc.) compounds are known as sillenites having fascinating photorefractive characteristics. The present paper reports the structural and optical characteristics of one of the members of this family, Bi12TiO20 single crystals, grown by Czochralski method. X-ray diffraction pattern of the crystal presented sharp and intensive peaks associated with planes of cubic crystalline structure with lattice constant of a = 1.0142 nm. The optical properties were studied by means of room temperature Raman and temperature-dependent transmission experiments at various temperatures between 10 and 300 K. Raman spectrum indicated peaks around 127, 162, 191, 219, 261, 289, 321, 497 and 537 cm(-1). The analyses of transmittance spectra indicated the increase of direct bandgap energy from 2.30 to 2.56 eV as temperature was decreased from room temperature to 10 K. The temperature-dependent bandgap characteristics of Bi12TiO20 were analyzed by means of Varshni and O'Donnell-Chen models. The analyses under the light of these models resulted in absolute zero bandgap energy of E-g(0) = 2.56(4) eV, rate of change of bandgap energy of gamma = - 1.11 x 10(-3) eV/K and average phonon energy of < E-ph & rang; = 8.6 meV. WOS:000592613600005 2-s2.0-85096598213

This paper treaty with the preparation, characterization, and Optical and Dielectric studies of xCdI2–(100 − x)[0.444 Ag2SO4–0.555 (0.4TeO2–0.6B2O3) glass system, where x is the wt% of CdI2 varying from 0 to 25 with step 5. These systems were prepared by melt quenching method and characterized by Differential scanning calorimeter (DSC), X-ray diffraction (XRD), and Fourier transforms infrared (FTIR) spectra. Physical parameters such as the density of materials, molar volume, average molecular weight, refractive index, oxygen mole present, polarizability, field strength, and Cd and Ag ions concentration were calculated. Based on optical absorption results, direct band gap Eg was premeditated by comparing Tauc’s plots and the ASF method. From these optical absorption results, Urbach energy (Eu) also calculated. Second-order deformation potential and free energy of the system have been resoluted by expending relation between Eu and Eg. Variation of these factors by changing the CdI2 composition is deliberated in detail. Refractive index, dielectric constant at optical and electrical frequencies have been discussed in detail.

Unlike conventional organic liquid electrolytes, which have uncontrollable lithium dendrite growth and serious safety concerns, gel polymer electrolytes (GPEs) are widely considered to be one of the best candidates for the next generation of high energy density lithium metal batteries (LMBs). However, the challenge of maintaining high mechanical strength and good electrochemical stability simultaneously has not yet been met by these materials. Therefore, in this paper, we designed bayberry silica nanoparticles (BSNPs) with ultra-high specific surface area and compounded them with polyvinylidene fluoride – hexafluoropropylene (PVDF-HFP) (BSNPs-CPE) to effectively solve these problems. The results show that compared with the blank sample and industrial silica nanoparticles (SNPs-CPE) composite electrolyte, BSNPs-CPE not only has higher absorption rate and ion conductivity but also has a higher lithium-ion migration. In addition, due to the good compatibility between BSNPs-CPE and lithium metal, a stable SEI layer can be generated. At the same time, lithium metal batteries of BSNPs-CPE exhibit good cycling performance and rate capacity. After 300 cycles, the excellent capacity of up to 147.2 mAh g− 1 remains at the current rate of 1.0 C. More encouragingly, the capacity of 119 mAh g− 1 was obtained at the current rate of 10 C, which keeps much higher than that of the blank sample (76.2 mAh g− 1). This kind of nanostructure with micropore and high specific surface area provides important significance for the design of high-performance lithium metal battery.

Semiconductor photocatalysis technology is one of the ways to control environmental pollution using solar energy. Because of its chemical stability, low toxicity and high photocatalytic oxidation-reduction ability, titanium dioxide has become one of the most widely studied and applied semiconductor photocatalytic materials. However, there are also some problems such as the response only in the ultraviolet range, rapid recombination of electron pairs produced by light during photodegradation, and the small specific surface area. On account of the limitations of titanium dioxide photocatalyst, the key factors and breakthroughs to improve performance new materials, this paper uses g-C3N4 of improving the photocatalytic function of titanium dioxide. Because g-C3N4 has good conductivity, relatively strong adsorption capacity and larger specific surface area compared with other carriers, g-C3N4 is one of the most promising carriers. In this research work, g-C3N4/TiO2 heterogeneous nanocomposites were prepared by combining TiO2 nanowires with g-C3N4. First of all, we need to change the morphology of titanium dioxide. We use high-voltage electrospinning technology to achieve this goal. This method greatly increases the specific surface area and increases the active sites involved in photocatalytic activity. Then, g-C3N4 was prepared with melamine as raw material by high temperature calcination. Then, the hydrothermal method combined with the good characteristics of g-C3N4 enhanced the deflection of photogenerated electrons and prolongs the lifetime of photogenerated electron-hole pairs. The photocatalytic efficiency of nanocomposites is greatly improved Rhodamine B solution was completely degraded in 120 min.

This very paper focuses on the preparation of an eco-friendly and efficient photocatalyst aiming to degrade organic dyes in wastewater. The cheap and abundant straws were carbonized to prepare porous carbon pieces in this study. A simple hydrothermal method was employed to prepare the porous carbon/CdS (PC/CdS) composite. CdS nanoparticles were anchored on these porous carbon sheets, forming the PC/CdS composite. The composite was annealed at 300, 400, and 600 °C, respectively, and then these samples were characterized by SEM, TEM, XRD, and FTIR. As an important parameter, the porosities of PC and the PC/CdS were characterized by BET method. Particularly, the photo-electronic response of PC/CdS has been characterized by EIS, PL, and transient photocurrent. It is found that the carrier mobility and shape of PC itself and the annealing process improved the photocatalytic activity, as well as adsorption ability. Those composites were able to thoroughly degrade RhB within 90 min under the irradiation of visible light. What is interesting and quite different from other reports is that there was no conjugated part of RhB left in the solution after photocatalytic degradation.

© 2020, Springer Science+Business Media, LLC, part of Springer Nature.This paper reports that frequency response on profile of C–V–ƒ and G/ω–V–ƒ characteristics of spin-coated nanographite (NG)-doped polyvinylpyrrolidone (PVP)/n-Si structures in a wide frequency (1 kHz–5 MHz) and voltage (± 3 V) ranges at room temperature. Hereby, the basic parameters of the structure such as diffusion potential (VD), doping donor density (ND), Fermi energy level (EF), maximum electric field (Em), depletion layer thickness (Wd), and barrier height (ΦB) are derived by using the intercept and slope of C−2–V–ƒ plot for each frequency. Additionally, the energy density distribution of surface states (Nss) and their relaxation time values (τ) are also attained from the conduction method and their values are found as 4.999 × 1012 eV−1 cm−2 and 2.92 µs at 0.452 eV, and 3.857 × 1012 eV−1 cm−2 and 164 µs at 0.625 eV, respectively. The lower Nss values are the consequence of passivation effect of the used nanographite (NG)-PVP polymer interlayer. As a result, the polymer interlayer based nanographite (NG)-PVP is candidate instead of the widely used oxide/insulator layer for the purpose of decreasing the surface states or dislocations.

In this paper, sol-gel self-propagation is used as the experimental method, and glucose is used as the complexing agent to prepare magnesium–cobalt ferrite (Mg0.1Co0.9FeO4). In the experiment, the annealing temperature of the sample is changed to study the annealing temperature on the ferrite. The influence of the microstructure and magnetic properties. In order to explore the samples, (X-ray diffractometer) XRD, (Fourier infrared spectrometer) FTIR, (scanning electron microscope) SEM and (vibrating sample magnetometer) VSM are usually used to characterize the sample. The characterization results of the samples are analyzed to prove the changes in the microstructure and magnetic properties. There are several obvious diffraction peaks in the XRD diffraction patterns of the five samples. Analysis of the positions of the diffraction peaks can prove that the prepared samples have a pure phase spinel structure. In the Fourier infrared spectroscopy, there is an obvious absorption peak around 580 cm−1. The presence of this absorption peak can also prove that the sample has a spinel structure. The morphology of the sample in the SEM photograph of the sample is round or elliptical, and the particle distribution is obvious, and the size is 100 ~ 200 nm. Vsm tested the magnetic properties of the samples. On the hysteresis loop of each sample, can see that the saturation magnetization and the residual magnetization of the sample reached the maximum when the annealing temperature was 500 °C. When the annealing temperature was 600 °C the coercive force and magnetic susceptibility of the sample reached maximum.

In this paper, adipic acid crystals were grown using slow evaporation method in aqueous solution of l-alanine at room temperature. X-ray diffraction investigation shows that the crystal belongs to P21/n space group. EDAX study confirms the occurrence of elements in the crystal. The crystal is thermally stable up to 124 °C. Further, the grown crystals were exposed to Co-60 gamma radiations with different doses of 1 Mrad, 3 Mrad, and 5 Mrad at normal room temperature. After gamma irradiation, a small change in the intensity and a slight shift in the Powder X-Ray Diffraction (PXRD) peaks were seen. UV–visible analysis reveals an increase in reflectance after gamma irradiation. Increase in dielectric constant, dielectric loss, and AC conductivity was observed by dielectric studies. Second Harmonic Generation (SHG) efficiency of the crystal is 0.42 times that of the standard Potassium Dihydrogen Phosphate (KDP) crystal and is increased moderately up to the gamma irradiation dosage of 3 Mrad.

This paper reports a facile one-step reaction method to prepare rGo/Co hybrids with super-tiny Co nanocrystals coating on reduced graphene oxide, the rGo/Co hybrids have excellent electromagnetic wave absorption ability because of its good impedance matching and attenuation properties. The crystal structure, microtopography, and magnetic property of rGOs/Co hybrids were characterized by X-ray diffraction, transmission electron microscope, and vibrating sample magnetometer, respectively. Electromagnetic parameters were measured by vector network analyzer in the frequency range of 1–18 GHz using a coaxial line method. The rGOs can serve as perfect supports for dense coating of Co nanocrystals with an average size of 3.87 nm. Compared with pure rGOs and Co NPs, the rGO/Co hybrids exhibit excellent electromagnetic wave absorption properties with an optimal reflection loss (RL) value reaching up to − 52.73 dB at 14.34 GHz and a broad effective bandwidth (RL values lower than − 10 dB) of 6.2 GHz (11.8 to 18 GHz) at a thin thickness of 2.1 mm only. This work provides an efficient process to prepare a micro-nano composite absorber with strong and broadband electromagnetic wave absorption.

In this paper, a comparative study between irradiation-induced defected mixed carbon nanotube bundle (MCB) and copper based interconnects concerning functional crosstalk as well as dynamic crosstalk, at the far end of both aggressor and victim lines, are presented at 14 nm technology node for a temperature range (300 K-500 K). Four different structures of MCB namely ST-1, ST-2, ST-3 and ST-4 are taken for the analysis. If the temperature increases from 300 to 500 K, each structure of MCB with irradiation-induced defect is showing larger propagation delay as compared to defect-free MCB structures. Due to irradiation-induced defect, there is a considerable increase in crosstalk induced noise peak and duration in every MCB structure. The results further reveal that crosstalk-induced noise voltage peaks of the victim output are found to be larger in copper as compared to MCB. Also, the ST-4, considering with defect(WD) and without defect(WOD), has smaller crosstalk induced delay and time duration with higher noise voltage peaks of the victim output pulse among other structures of MCB. Moreover, the crosstalk-induced delay of coupled interconnects of the best structure of MCB (i.e. ST-4), considering irradiation-induced defect, is evaluated using the temperature-dependent (TD) and temperature-independent (TID) circuit models at different interconnect lengths (200 µm–1000 µm).

The paper reports the fabrication of fluorine-doped zinc oxide/p- silicon (ZnO/p-Si) heterojunction solar cells and the effects of fluorine content on efficiency of these solar cells. Fluorine-doped zinc oxide nanoparticles (FZO) were synthesized using sol–gel method and heterojunctions of n-FZO/p-Si solar cells were fabricated by the spray pyrolysis technique. FZO thin films were also deposited on the glass substrate under the same conditions for the investigation of their optical properties. The structural characterizations of FZO films were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Optical characterization of these thin films was studied by UV–Vis spectroscopy and transmittance values of over 84% were obtained at the visible region. The current–voltage characteristic of the n-FZO/p-Si heterojunction solar cells was measured at room temperature in the dark and under illumination (90 mW/cm2). Series resistance (Rs) values obtained from solar cells were found between 5.52 and 10.12 Ω. The conversion efficiency of the fabricated solar cell of between 3.82 and 6.74% was obtained.

In this paper, NdFeO3 nanoparticles were synthesized by the co-precipitation method. The particle size of NdFeO3 nanoparticles was controlled by changing the NaOH concentration in the co-precipitation method, mainly because NaOH concentration could control grain growth. The samples were characterized by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). They were found that with the change of NaOH concentration, the lattice parameters and cell volume of NdFeO3 nanoparticles changed little, but the average particle size ranged from ~ 100 to ~ 142 nm. And the influence of particle size on electrical properties of samples was also explored. The results showed that the dielectric constant of the sample increased with the decrease of the average particle size, and the dielectric loss decreases. When the average particle size was ~ 100 nm and the frequency was 103 Hz, the dielectric constant (e′) was at most (~ 1.4 × 104) at room temperature, indicating that it had potential applications in dielectric capacitors. In addition, the conduction mechanism of NdFeO3 nanoparticle was studied by frequency dependence of AC conductivity. The effect of the grain and grain boundaries of NdFeO3 nanoparticles on the electrical properties of material was observed in complex impedance spectroscopy. The grain boundary resistance played a leading role in the resistance of the material, and the values of resistance increased with the decrease of the particle size.

In this paper, Ba(Mg1/3Nb2/3)O3 (BMN) ceramics with x (x = 0–9) wt% BaWO4 were synthesized using the conventional solid-state sintering technique. Effects of BaWO4 addition on the microstructure and microwave dielectric properties of BMN ceramics were evaluated. X-ray diffraction (XRD) analysis showed that there were three phases: main crystalline phase Ba(Mg1/3Nb2/3)O3 and secondary phases BaWO4 and Ba5Nb4O15. Meanwhile, the (100) super-lattice reflection peaks shifted to a higher 2θ angle with increasing BaWO4 content. SEM photographs suggested that BaWO4 working as a sintering additive promoted the densification and grain growth. The dielectric properties were examined by Vector network analyzer. The dielectric constant (er) was largely determined by the relative density and phase composition. Meanwhile, the addition of BaWO4 had a positive effect on the Q × f value, for example the specimen with x = 5 possessed the highest Q × f value of 111,300 GHz. Optimum microwave dielectric properties (er = 31.7, Q × f = 111,300 GHz (f = 8 GHz) and τf = 0.16 ppm/°C) were obtained for the specimen with x = 5 sintered at 1350 °C for 6 h.

In this paper, 0.5 wt% carbon nanotubes (CNTs) and 0.05 wt% graphene nanosheets (GNSs) were selected as additives to modify the properties of Sn–Cu–Ni solder joints for solar cell. The mechanical properties of Sn–Cu–Ni solder joints can be improved by 20–25%. The interface growth behavior of Cu–Sn intermetallic compounds at Sn–Cu–Ni/Cu and Sn–Cu–Ni–0.5CNTs–0.05GNSs/Cu couples after 250 °C and 260 °C soldering with 10 min and 20 min. The experimental results indicate that the growth rate of Cu6Sn5 IMC of Sn–Cu–Ni/Cu solder joints is higher than that of Sn–Cu–Ni–0.5CNTs–0.05GNSs/Cu solder joints. That is, adding 0.5 wt% CNTs and 0.05 wt% GNSs can reduce the growth rate of the Cu6Sn5 IMC layer, which can be attributed to the reduction of the element diffusion coefficient. In addition, the stress–strain of the two solder joints were calculated using finite element method, it is found that the Sn–Cu–Ni–0.5CNTs–0.05GNSs/Cu solder joints have significantly less stress–strain than Sn–Cu–Ni/Cu solder joints, due to the reduction of Cu6Sn5 layer thickness, fatigue life of solder joints can be enhanced by three times.

In this paper, the thickness effect of tin-doped zinc oxide (SZO) thin films on structural, morphological, optical, and electrical properties have been investigated for optimal SZO/p-Si heterojunction. For that, a series of SZO films were deposited on glass substrates by the sol–gel spin coating method at different cycles (5, 10, 15, 20, and 25) with a concentration of Sn doping fixed at 5%. The X-ray diffraction exhibits that all films are polycrystalline with hexagonal wurtzite structure highly oriented along the c axis. The surface morphology visualized by scanning electronic microscopy (SEM) and atomic force microscopy (AFM) analysis shows a homogeneous granular structure, less rough, with a grain size which increases with the film thickness. UV–Visible spectroscopy shows a good optical transmittance of about 90% in the visible range and a high absorption in the UV domain, the maximum value of gap energy is 3.24 eV. Hall effect measurements reveal that electrical resistivity is limited both by the density and the mobility of the charge carriers according to the thickness of the elaborated films. Finally, the SZO/p-Si heterojunction that we elaborated showed a rectification behavior with an ION/IOFF ratio of 12.92 at 2 V, a turn-on voltage of 3.24 V and an ideality factor of 6.91 in dark. Under illumination, the structure shows the following photoelectric parameters ISC = $$1.12\times {10}^{-7}$$ A, VOC = 0.39 V, and FF = 30.82%.

The structure and surface properties of the sensing materials have been considered as the main factors for the fabrication of metal–oxide semiconductor gas sensors. In this paper, a one-step hydrothermal method for the preparation and control of the morphology of α-Fe2O3 is reported. The results show that the amount of glycol has a great influence on the morphology of the products. With the variation in ethylene glycol concentration (from 30 to 110 ml), we can obviously see the product was assembled into three-dimensional porous α-Fe2O3 micro-flower structure from two-dimensional nanochips from scanning electron microscope (SEM) pictures. When the ethylene glycol was 70 ml, the micro-flower structure was the most uniform and perfect. It additionally showed the largest specific surface area (63.69 m2/g) and the biggest oxygen vacancy in nitrogen adsorption–desorption and XPS analysis. Further gas sensitivity test showed that gas sensitivity was also the best. Under the low operating temperature (210 °C), the porous α-Fe2O3 micro-flower (70 ml glycol) showed the highest response (49.4) to 100 ppm acetone, the sensitivity of other materials was 8.2/30 ml, 14.7/40 ml, 38.4/50 ml, 36.7/90 ml, 10.3/100 ml, 4.8/110 ml, respectively. In addition, the porous α-Fe2O3 micro-flower (70 ml glycol) has excellent selectivity, short response/recovery time (1 s/31 s), low detection offline (2.2 to 0.2 ppm acetone), and good stability. The reason for the improvement of gas-sensing performance is mainly due to the change of morphology, decrease of crystallite size, the increase of oxygen vacancy, and specific surface area.

The synthesis of Ti3Al(Sn)C2 usually uses elemental powder as the raw material, and the synthesis temperature is up to 1500 °C. Low-temperature ceramic sintering is the key to inhibit the formation of competitive phases and reduce the ceramic sintering cost. In this paper, a new method of low-temperature synthesis of Ti3Al(Sn)C2 was proposed, and high-purity Ti3Al(Sn)C2 sample was successfully prepared at low temperature by using the replacement reaction method. Research shows that the temperature of 600 °C for 5 h is the optimal process conditions for Ti3Al(Sn)C2 synthesis. Furthermore, the introduction of Sn changed the high-temperature oxidation resistance of Ti3AlC2. Compared to pristine Ti3AlC2, the oxidation resistance of Ti3Al(Sn)C2 at 900 °C increases by 33%. The comparative analysis of the formation energy of replacement Ti sites and Al sites shows that the formation energy of Sn-replaced Al sites is lower. These results have broad reference implications for low-temperature synthesis of other MAX phases.

Recently, rGO has been widely used in gas-sensitive research because of its high conductivity and large specific surface area. In this paper, rGO/MoO3 nanocomposites were first synthesized via a hydrothermal method, and then the ternary rGO/MoO3/Au hybrid nanomaterials were synthesized by adding Au nanoparticles. Its structure and morphology were fully characterized by SEM, TEM, EDS, XRD, TG and other methods and the results show that the three components are well combined. Then rGO/MoO3/Au gas sensors were prepared and their performance was tested. 160 °C is the optimal operating temperature, and the response to 10 ppm TMA can reach 68.5 at this temperature, which is much higher than pure MoO3 and rGO/MoO3. At the same time, it has good selectivity and repeatability. The reason is that the p–n heterojunction generated at the interface between rGO and MoO3 and the catalytic activity of precious metal Au nanoparticles can improve the gas-sensitive properties of the material.

In this paper, polyimide (PI) films were modified by using non-thermal plasma, which was generated by dielectric barrier discharge (DBD) in atmospheric air. Under repetitive impulse voltage, the lifetime of plasma treated PI films increases obviously, which reaches the maximum value of 16.8% higher than that of untreated PI films, obtained by 20 s’ treatment. For further understanding lifetime improvement mechanism, energy level distribution of both electron-type and hole-type traps was calculated based on isothermal surface potential decay (ISPD) measurement. It is found that energy level of both shallow and deep traps decrease after treatment, reaching the lowest value for the films treated for 20 s. Lower energy for shallow trap is beneficial to charge dissipation, so that local electrical field would be mitigated. Furthermore, lower energy for deep trap results in less amount of trapped surface charges. Thus, surface PD intensity would be suppressed, ending up with longer lifetime. Analysis of chemical bonding structure reveals that active groups rich in oxygen and nitrogen were introduced into the near-surface region of plasma treated sample, which are responsible for corresponding change of trap energy level distribution. However, in order to prolong lifetime effectively, plasma treating time must to be controlled in an appropriate range.

In this paper, using the hydrothermal method, we prepared α-Ag3VO4 loaded with nano-metal Pd. We performed X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet–visible diffuse reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and other technical means to test and characterize the prepared Pd-loaded α-Ag3VO4. By degrading rhodamine B and methyl orange under visible light, we studied the effect of different Pd loadings on the photocatalytic performance of α-Ag3VO4. The results show that when the Pd loading is 3.5 wt%, the photocatalytic performance of α-Ag3VO4 increases the most. However, if the Pd loading continues to increase, the photocatalytic activity of α-Ag3VO4 will decrease. This is because the addition of an appropriate amount of precious metal Pd can accelerate the separation of electrons and holes in α-Ag3VO4, generating more active free radicals in the photocatalytic process. However, when the metal Pd content is too high, the metal Pd itself will become the active center of electron–hole recombination, leading to the decrease of α-Ag3VO4 photocatalytic activity.

In this paper, Co-doped molybdenum disulfide anchored on the surface reduced graphene oxide (Co@MoS2/rGO) has been successfully synthesized using a simple and effective hydrothermal approach to measure their microwave shielding properties. The X-ray diffraction (XRD) technique confirmed the successful doping of magnetic atoms into the MoS2 lattice. The experiments show that 15% and 20% Co@MoS2/rGO nanocomposite have higher electromagnetic interference shielding effectiveness (EMI SE) value up to SET ~ 38.26 and ~ 46.02 dB, respectively. But pure MoS2/rGO nanocomposite demonstrates a lower EMI SE value of around ~ 28.90 dB over the frequency range of 8.0–12.0 GHz with a 1.7 mm thickness. A higher value of the EMI SE depends mainly on the doping percentage of Co-ion. This nanocomposite network enhances the defect dipole polarization, electric conduction, interfacial polarization, and impedance matching characteristics. It is favorable for strong attenuation and dissipation loss ability of microwave energy inside the shielding material. The actual role of Co-doping is to form a highly conductive and magnetic channel between multi-interfaces leading to enhance the migration and hopping of electrons at defective sites or interface. Therefore, the 20% Co@MoS2/rGO nanocomposite is considered as novel microwave shielding material and can be widely used in electronic information and communication devices.

In this paper, we reported a new method to fabricate Cu2ZnSnS4 (CZTS) thin film solar cells. Oxygen containing precursor thin films were deposited on the Mo-coated soda lime glass (SLG) by sputtering ZnO, SnO2 and Cu targets. For getting higher quality CZTS thin films, the effects of different annealing temperatures of 380 °C, 480 °C, 580 °C and 650 °C on CZTS films were systematically investigated. The results showed that the optimum annealing temperature was 580 °C. Through optimizing the sulfurization process, phase-pure CZTS thin films with compact and large grains were obtained. Composition analysis showed that O was not detected after sulfurizing process which indicated all of O was replaced by S. And due to the stability of SnO2, the loss of tin can be avoided. In addition, ZnO not only can provide zinc sources, but also can decrease the thickness of MoS2 as a barrier layer. Finally, CZTS solar cells based on sputtering oxides targets were obtained and the preliminary fabricated CZTS thin film solar cells had an efficiency of 5.08%, with an open-circuit voltage of 645 mV, a short-circuit current density of 21.74 mA/cm2 and a fill factor of 36.23%.

Photocatalysis technology has received much attention on the treatment of antibiotics residues. In this paper, CdS quantum dots (QDs)-decorated TiO2 (CDS-T for short) have been prepared successfully through a photodeposition method and utilized as photocatalysts for degradation of metronidazole (MTZ). Under visible light irradiation for 60 min, the degradation ratio of MTZ over CDS-T-3 that was prepared by 3 h of photodeposition reached up to 90.9%, which was 1.5 times than that reached over commercial CdS. The decoration of CdS QDs onto TiO2 can enlarge light absorption range to visible region. Furthermore, greatly improved separation efficiency of photogenerated carriers is realized through forming heterojunction. Activity control experiments demonstrate that O2·− serve as the main active species, while ·OH and holes (h+) play secondary roles on the MTZ degradation. Moreover, electron spin resonance (ESR) technique, terephthalic acid photoluminescence (TA-PL) technique and N,N-diethyl-p-phenylenediamine (DPD) method confirm that larger amounts of active species are generated from CDS-T-3 than that from commercial CdS under visible light. This study can not only offer an easy method to prepare CdS quantum dots-decorated TiO2 but also enlarge its application in solving the problem of metronidazole contamination.

The rapid growth of industrialization has driven the development of wastewater treatment technologies to overcome the environmental pollution that comes with it. Organic-based pollutants such as dyes and petroleum-based hydrocarbons are known to be the major pollutants from industries. Advanced photocatalysts is an alternative solution for organic pollutants clean up without the generation of toxic by-products. In this paper, a forthright dye removal technique by CCTO/SiO2 core–shell composites produced via chemical precipitation was introduced. The core–shell CCTO/SiO2 composites were produced from a silica precursor, i.e. TEOS. The effects of TEOS content (x = 0.5 and 1 ml) on the morphology, structure, and photocatalytic activities of core–shell CCTO/SiO2 composites were studied. The phase compositions and structural properties of core–shell CCTO/SiO2 composites were analyzed by TEM-EDAX, XRD, FTIR, and BET. The particle and crystallite sizes of core–shell CCTO/SiO2 composite produced with higher TEOS content (x = 1 ml) were smaller, i.e. 380 ± 57 nm and 42 nm respectively. However, higher surface area (8.23 m2g−1) was observed. The photodegradation efficiency (η%) of core–shell CCTO/SiO2 composite prepared using 1 ml of TEOS was 76.5% after 40 min exposure to UV light; better than product from the system with 0.5 ml TEOS. The C1S photocatalyst was very stable with a high photodegradation efficiency of 73.5% even after 4 cycles of RhB degradation.

In this paper, we report one-pot fabrication of Fe3O4 nanoparticles electrochemically decorated onto porous graphene nanosheets (PGNs) as high-performance nanocomposite for energy storage applications. In this regard, a novel and facile electrophoretic/electrochemical deposition (EPD/ECD) method was developed for the fabrication of binder-free high performance Fe3O4@PGNs/Ni foam. For comparison, pristine Fe3O4/Ni foam and PGNs/Ni foam electrodes were also fabricated via electrochemical and electrophoretic methods, respectively. The prepared materials were characterized by XRD, FT-IR, FE-SEM, TEM, TGA/DSC and BET techniques. The results confirmed co-deposition of Fe3O4 particles and porous graphene sheets onto the surface of Ni foam. The capabilities of the fabricated electrodes (i.e. Fe3O4/Ni foam, PGNs/Ni foam, Fe3O4@PGNs/Ni foam) were investigated as the binder-free electrodes for supercapacitor applications. The composite electrode showed specific capacitance as high as 892 F g−1 at the current density of 0.5 A g−1, where Fe3O4/Ni foam, PGNs/Ni foam electrodes exhibited only 312 F g−1 and 401 F g−1, respectively. Furthermore, the rate capability of the Fe3O4@PGNs/Ni foam electrode was found to be 73.2% as the current density increased to 10 A g−1, which was much higher than those of both pure Fe3O4/NF and PGNs/NF electrodes (i.e. 40% and 59%, respectively). In addition, the cycling stabilities of the composite electrode were measured to be 95.2% and 87.6% after 4000 successive charge/discharge cycles at the current densities of 2 and 5 A g−1, where the pristine Fe3O4/Ni foam exhibited capacity retentions of 81% and 67% at the current loads of 2 and 5 A g−1, respectively. The obtained results confirmed an outstanding performance of the fabricated Fe3O4@PGNs composite electrode as compared with single-component electrodes (i.e. Fe3O4/Ni foam, PGNs/Ni foam). These findings implicated the positive synergistic effects between Fe3O4 and porous graphene nanosheets to exhibit high supercapacitive performance.

This paper presents the ionizing radiation effects on current-voltage (I-V) characteristics of Au/TiO2/n-Si metal-insulator-semiconductor (MIS) structure. The TiO(2)film as the dielectric interface layer of Au/n-Si was deposited using RF magnetron sputtering method. The MIS structure was exposed to gamma irradiation from Co-60 source with the dose rate of 0.69 kGy/h, and it was irradiated in the range of 0-100 kGy. The electronic parameters such as barrier height (phi(b0)), ideality factor (n), series resistance (R-s), and interface state density (N-ss) of the MIS structure were calculated from the measured I-V data. Experimental results showed that all calculated parameters change with the irradiation dose rate. To determine current conduction mechanisms of the MIS structure, the In (I-F) vs In (V) and In (I-R) vsV(1/2)curves for all irradiation doses are plotted under both forward bias and reverse bias, respectively.

MXene belongs to the family of 2D carbides and nitrides. The controlling of process parameters is key to obtain high-quality MXene films. The layered structure of MXene is obtained successfully by tuning the process parameters which is confirmed through the presence of XRD peak (110) at 2 theta value of 60 degrees. Moreover, the accordion-like structure of MXene is confirmed through SEM which is also highly dependent on the process parameters. It is also observed that if the etchant with sufficient concentration is used for an optimised time the (002) peak gets shifted to a lower angle and confirms the increase in spacing of MXene layers to 12.92 A. Further reduction in the etching time leads to a decrease in the d-spacing of MXene layers due to the presence of aluminium and the presence of defects corresponding to the unsuccessful removal of AlF3 by-products which is confirmed by (106), (108) and (109) XRD peaks. However, the occurrence of (106), (108) and (109) peaks which correspond to the growth of AlF3 is highly dependent on any variation in process parameters. The increase in the quantity also impacts the properties of MXene formed. It can be seen that increasing the quantity of hydrofluoric acid will lead to thicken the MXene layers. If etching is done for the greater quantity of HF, the toxicity is increased which leads to the greater number of fluorine groups which will lead to an increase in the number of defects in the MXene material. This paper also discusses the correlation of process parameters with that of the electrical properties of MXene layers. It is found that to get the best MXene layers in terms of structurally and electrically, the process parameters need to tune in such a way that the etching of aluminium can be done completely without increasing the fluorine content in the MXene. Herein, we report for the first time the fabrication of best optimised MXene film on the flexible polypropylene (PP) substrate using the best optimised parameters for supercapacitor applications and compared with the Polyethylene terephthalate (PET) and glass substrate results. The PP-supported MXene device exhibits lower contact resistance of 141 ohms and the areal capacitance of 82.6mF/cm2 at 5 mV/s and capacitive retention of 73.3%. The study opens up new possible designs for the high-performance devices employing different flake sizes, morphologies of MXene and their combinations.

At present, there have been many researches on the effect of trace elements on the mechanical properties of Sn–Ag–Cu solder, and the methods used are mainly shear test or nanoindentation test. However, the size of structural solder joints in electronic packaging has reached the order of micrometers, and the mechanical behavior characteristics related to the strain rate of solder at the micro-scale are obviously more needed for the application of small-scale structural solder joints. For this reason, this paper selects Sn0.3Ag0.7Cu solder with superior comprehensive properties such as ductility and shear strength and low cost, and uses universal testing machine and Split Hopkinson Pressure Bar to perform quasi-static and dynamic compression tests on it. After fitting the Johnson–Cook constitutive model parameters of Sn0.3Ag0.7Cu, the dynamic indentation process at the micro-scale was simulated by ABAQUS, and the effect of strain rate on the mechanical behavior of the material at the macro-scale and micro-scale was analyzed, respectively. Our macro test results show that the yield strength of Sn0.3Ag0.7Cu solder is about 28.74 MPa. Under quasi-static load, the rate of increase of the stress value in the strain hardening stage will increase with the increase of the strain rate; while under dynamic load, the stress value corresponding to different strain rates does not increase significantly, and the main difference lies in the magnitude of plastic strain. In our numerical simulation of dynamic indentation, the result shows that when Sn0.3Ag0.7Cu solder is subjected to a high strain rate load at the micro-scale, a certain degree of hardening occurs in the middle and late stages of indentation propagation. At the same time, the calculated load–displacement curves indicate that the plastic flow ability of Sn0.3Ag0.7Cu solder in the micro-scale increases with the increase of the indentation expansion rate.

A series of Fluorapatite-structured phosphors with structural formula Y6Ba4(SiO4)6F2 (YBSF) doped with different mol% (0.2, 0.4, 0.6, 0.8 & 1) of terbium were synthesized by solid-state reaction method and its structural and photoluminescence (PL) properties were studied. X-ray diffraction (XRD) patterns confirm that the prepared phosphors were successfully synthesized in the form of hexagonal crystal structure with space group P63/m. Prepared phosphors are polycrystalline in nature with rod-like structure and all the initial reactants were present. Presence of Si–H stretching in Fourier transform Infrared spectroscopy confirms the successful incorporation of terbium ion in the Host lattice. Photoluminescence excitation and emission spectra of the as-prepared phosphors show different transition of 4f8–4f75d and 4f–4f; moreover, the prepared phosphors when excited with 250 nm show blue emission due to 5D3–7FJ and show green emission due to 5D4–7FJ when excited by 290 nm. The results indicate that the emitted wavelength depend on excited wavelength and, therefore, can be tuned accordingly. The mechanism behind color tuning is due to cross-relaxation process which is discussed in detail in the present paper. The prepared phosphors showed high quantum efficiency with satisfactory thermal stability. Commission Internationale de I’Eclairage chromaticity coordinate also shows the shifting from blue region to green region for the prepared phosphors.

Metal semiconductor oxides are widely used in the field of gas sensors in recent years due to the advantages of good gas sensitivity, low raw material cost and facile preparation. To achieve more sensitive, accurate and rapid detection of ethanol gas, tetrakaidecahedral ZnSnO3 nanoparticles were successfully synthesized by means of a facile template-free co-precipitation method. The nano-Ag particles were decorated evenly on the surface of the ZnSnO3 particles with a heat treatment at 250 °C. The as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). The results of gas sensing test experiment show that the tetrakaidecahedral ZnSnO3 decorated by nano-Ag (Ag@ZnSnO3) sample has excellent gas sensitivity properties to ethanol at 220 °C. In particular, the composite Ag@ZnSnO3 material gas sensor has a short response time of 2 s and recovery time of 23 s as the nano-Ag modification ratio is 5%. The responsivity of the Ag@ZnSnO3 gas sensor with a modification ratio of 5% to the 500 ppm ethanol is 258 at 220 °C, which is 2.83 times of the pristine ZnSnO3 gas sensor. The minimum limit detection of the sensor to ethanol is 2 ppm. The research in this paper confirms that Ag@ZnSnO3 composite material has potential application prospects in the manufacture of high-performance ethanol sensors.

Cu-to-Cu interconnection has drawn increasing attention as the bump pitch is decreasing continuously. Cu-to-Cu interconnections exhibit excellent mechanical, electrical, and thermal properties without forming IMCs, which usually degrade the interconnect reliability due to their brittle nature. In this paper, Cu-to-Cu interconnection can be realized at 150 °C for 10 min under a pressure of 3 MPa. The microstructure of the nanoporous Cu coarsened significantly and the interfaces of the bondline can not be distinguished clearly after bonding at 250 °C for 30 min under a pressure of 3 MPa. The microstructure was more densified along the bonding interface than the rest part, and the degree of densification was increased with the increasing bonding temperature and pressure. The average resistivity, thermal conductivity, and shear strength of the bondlines were determined to be 4.12 μΩ cm, 176.49 W m−1 K−1, and 18.78 MPa, respectively. After aging at 200 °C for 300 h, the shear strength was increased by 44.5% due to the increased densification rate brought by the diffusion of Cu atoms, which confirmed the Cu–Cu interconnection reliability during long-term service.

GdFeO3 perovskite attracted large interest in different fields thanks to peculiar magnetic and optical properties that are further tunable by means of doping processes and achievable on both Gd and Fe sites or by properly choosing the synthesis routes. In this paper, nanometric GdFeO3 compounds, undoped and doped with diamagnetic Ca2+ and Mg2+ ions, were synthesized by microwave assisted, sol–gel, and polyol syntheses and characterized by X-ray diffraction, showing solid solutions formation. Raman spectroscopy allowed us to confirm, from peak enlargements, the Ca and Mg substitution on Gd and Fe sites, respectively. The magnetic data showed the presence of magnetic domains as consequence of doping with diamagnetic ions, which seem to play a crucial role in the magnetic activity of the compounds. A superparamagnetic behaviour is evidenced; nevertheless, its intrinsic character is not definitely demonstrated. Indeed, the possible presence of traces of magnetic impurities, which are easily obtainable in these samples, such as iron oxides, must be taken into account.

In this paper, we have reported that the field emission properties of multiwall carbon nanotubes (MWCNTs) were significantly increased by decorating their surface by iron oxide nanoparticles. MWCNTs were prepared on silicon substrate through low-pressure chemical vapour deposition using acetylene as source gas. The iron oxide nanoparticles were grown on the surface of MWCNTs by thermal evaporation technique. Modified surface morphologies of the prepared films were characterized through field emission scanning electron microscope (FESEM), Raman spectroscopy and X-ray diffraction. A significant change in current density, stability and turn-on voltage has been observed in iron oxide-coated MWCNT films. Decoration of iron oxide nanoparticles reduces turn-on voltage from 4 to 3.4 V/μm, while current density increases from 10.15 to 33.26 mA/cm2. For practical MWCNT-based field emission devices, it is necessary to improve the emission current density and stability. The excellent field emission parameters are obtained and calculated which make them useful for high-performance field emission-based devices. The mechanism of emission of electrons is well described by the Fowler Nordheim theory.

In this paper, urchin-like ZnO nanostructures were synthesized via a facile one-step hydrothermal method. CdS was deposited on the ZnO nanostructures by the deposition method. Field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were used to analyze the morphology and structure of samples. FESEM images show that urchin-like ZnO nanostructures gradually turn into flower-like CdS@ZnO nanostructures with the increase of deposition times. XRD patterns confirm that the ZnO nanostructures present hexagonal wurtzite crystalline structure and CdS@ZnO nanostructures have high crystallinity. UV-vis absorption spectra and photoluminescence spectra (PL) were used to characterize the optical properties of samples. The results show that CdS@ZnO nanocomposites have higher visible light utilization when compared with the pure urchin-like ZnO. Furthermore, the results of photocatalysis experiments show that the absorption towards visible light of ZnO is significantly enhanced because of the incorporation of CdS. This kind of material with excellent optical properties can be used in photocatalysis and optoelectronic devices.

In the present paper, we report the influence of phase segregation (hexagonal and monoclinic phase) of facile microwave-assisted BPO (BiPO4) nanostructures on optical and electrochemical properties for supercapacitor applications. The XRD patterns reveal pure phase formation of both the samples of BiPO4 synthesized at 300 °C and 600 °C (JCPDS #15-0766 and JCPDS #43-0637). Phase transition of BiPO4 from hexagonal to monoclinic phase obtained by sintering the sample (BP600) at 600 °C. The FWHM values of the X-ray diffraction peaks observed to decrease with an increase in sintering temperature, which can be ascribed to the enhancement of the crystallite size. The synthesized samples of BiPO4 are in the nanometer dimension, which also revealed through FESEM examination. FTIR, Raman, and PL spectroscopy also revealed the crystal structure symmetry distinction among the hexagonal and monoclinic BiPO4 phase. Specific capacity calculated from GCD (galvanostatic charge and discharge) analysis for BP300 and BP600 samples is 1074 Cg−1 and 451 Cg−1, correspondingly, at the current density of 1 Ag−1. The investigation divulges that the phase segregation plays a considerable utility in tuning the electrochemical performance of BiPO4 nanostructures as active electrode material for next-generation electrochemical capacitors application.

This paper reports a tailored structure, morphology, optical behavior, and growth evolution of catalyst-free ZnO nanostructures (ZONSs) synthesized on quartz substrates using the wet thermal evaporation method. The as-prepared samples were thoroughly characterized to determine the influence of varying rates of Ar and wet O2 gas flow (150, 250, and 350 sccm) on their overall properties. Scanning electron microscopy (SEM) images revealed the formation of high-quality ZONSs of various shapes, including nanowires, aligned nanorods, and nanorods-like tetrapods with different dimensions. X-ray diffraction (XRD) patterns displayed the most intense diffraction peak at (002), which was attributed to the preferred growth orientation and crystallinity of such nanomaterials. Photoluminescence (PL) spectra showed an enhancement in the peak intensity. The position of the ultraviolet emission peak of ZONSs was red-shifted as the gas flow rate increased. Raman spectra exhibited the high-intensity E2 and very weak (suppressed) E1L Raman mode for all samples, indicating the accomplishment of good crystal quality in wurtzite hexagonal crystalline ZONSs of the samples. Furthermore, the optimum flow rate for synthesizing high-density, superior quality, and higher nanocrystalline ZONSs was found to be 350 sccm. This work can contribute toward the development of the production of various nano-optical devices.

In this paper, a non-toxic water-soluble copolymer of isobutene and maleic anhydride (Isobam) was used for gelcasting of Ba0.5Sr0.5TiO3 (abbreviated as BST50) ceramics as both dispersant and gelling agent. The rheological properties and gelation behavior of BST50 suspensions have been investigated. BST50 suspension with 54 vol% solid loading and 0.1 wt% Isobam was optimized for the gelcasting process. Complex-shaped green bodies were prepared with homogeneous microstructure without large defects. BST50 samples sintered at 1500 °C were processed at a high relative density of 99.6%. The sample possessed a high dielectric tunability of 22% (30 kV/cm) and tanδ of 0.006 (1 kHz) which is decreased by 70% compared with that of dry-pressed samples. The present method has great potential in the preparation of other functional ceramics with complex shape and enhanced performance.

The paper reports on properties of the elastomer multimode optical channel waveguides. The waveguides were fabricated by the doctor blade technique using the nickel mold with the dimension of the core 50 × 50 µm2 and irradiated by gamma rays from 60Co source with the dose rate 1 kGy/h. The applied irradiations were 14.6 kGy and 33.9 kGy and we studied the influence of gamma rays on the properties of the elastomer waveguides. We measured transmission spectra, refractive indices and the waveguide propagation losses. The lowest values of the optical losses were 0.21 dB/cm at 1310 nm and 0.35 dB/cm at 850 nm in the samples irradiated with dose 14.6 kGy and 0.55 dB/cm at 1310 nm and 0.66 dB/cm at 850 nm for the sample irradiated with a higher dose 33.9 kGy. The average value of the optical losses at 650 nm was 0.78 dB/cm (dose 14.6 kGy) and 1.05 dB/cm (dose 33.9 kGy). Optical silicone elastomers have unique properties and can be used for the realization of the optical waveguides for interconnection or realization photonics structures for applications in extreme environments.

This paper discusses the growth and evolution of residual stresses in (0002) preferentially oriented aluminum nitride (AlN) layers on Si (111) wafers by sputtering technique for the development of micro-electro-mechanical system (MEMS) accelerometer. The microstructure of the deposited films exhibited vertical columnar structures. Residual stresses in the sputtered AlN films are − 1.2 GPa, − 0.8 GPa, and − 0.25 GPa for the film thickness of 600 nm, 750 nm, and 900 nm respectively. The effect of the residual stress on the piezoelectric MEMS acceleration sensor structure is analyzed. The presence of residual stress reduced the resonant frequency (up to 14.72%) and bandwidth (up to 27.3%) of the accelerometer. The locations of the von-Mises stress maxima are shifted from the beam edges (adjoining to the proof-mass) to the whole proof-mass area. The normalized stress sensitivity (which defines the piezoelectric charge sensitivity) is reduced by two orders due to the residual stress in the AlN layers.

This paper explore the ability of bismuth selenide (Bi2Se3) as an alternative light sensitizer for photoelectrochemical (PEC) solar cell. Herein, we applied novel chemical route, namely, chemical bath deposition (CBD) for growth of Bi2Se3 nanoparticles over spin-coated TiO2 at room temperature. The structural, surface morphological, and optical properties of TiO2/Bi2Se3 films are systematically studied. The deposition time for the growth of Bi2Se3 using CBD can enable to tune the size of Bi2Se3 nanoparticles over porous TiO2 which significantly influences the physical properties of resultant heterostructure. The potential of Bi2Se3 nanoparticles in PEC solar cell is demonstrated by preparing FTO|TiO2|Bi2Se3|polysulphide electrolyte|carbon-coated FTO device structure and tested with current density–voltage (J-V) and electrochemical impedance spectroscopy (EIS) measurements. The result presented in this study established that the photoconversion efficiency and electron life time of device are affected by deposition time for Bi2Se3 using CBD. The J-V measurement done with above-proposed devices shows maximum photoconversion efficiency around 0.152% for 20 min deposited Bi2Se3.

Many investigations employ oxides grown by spray pyrolysis whose desired features depend on the synthesis parameters. This paper reports the influence of precursor dilution on the structural, morphological, and optical properties of ZnO films. For this purpose, the applied aqueous solutions using zinc acetate as precursor covered a wide range of molarities from 10–3 to 1. The films were deposited on silicon and glass substrates and characterized by several techniques. X-ray diffraction showed that well-diluted conditions are essential for crystalline ordering. Atomic force microscopy and scanning electron microscopy confirmed extensive coating with rougher surfaces on silicon substrates. The optical transparency is remarkable, and the optical emissions measured by photoluminescence are predominantly in the ultraviolet range, related to near band edge transitions. X-ray photoelectron spectroscopy indicated surfaces with a high percentage of adventitious carbon. In contrast, at high molarities, the films are white and powder-like. Defect-level recombination dominates the optical emissions in the visible range. Moreover, the stoichiometric surfaces present lower levels of adventitious carbon. This investigation shows that the precursor molarity is crucial for ZnO films architecture, as demonstrated in their chromaticity characteristics by the redshift of UV emission and the raise of the visible band.