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Metallic mirror coatings with high reflectivity using Au thin films deposited onto a Borosilicate BK7 glass substrates by a sputtering technique using ionic coating system (KIC-1A) were investigated. In order to facilitate the process of calculating the relationship between deposition duration and thin film thickness to reach to a certain thickness, so we have described and calculated the relationship between deposition duration and thin film thickness by theoretical analysis and then simulated by polynomial function. This study showed the relationship between the reflection and thin film thickness, where the highest value of the reflective coatings of 90.5% was obtained at thin film thickness of 153 nm.

This study proposed an unclad optical fiber biosensor based on the localized surface plasmon resonance phenomenon and operating at 650 nm using COMSOL Multiphysics 5.1 finite element method (FEM). Gold nanoparticles (50 nm thickness) were coated on the middle portion of the unclad fiber. Air, water, blood plasma, liver tissue, colon tissue, and pentanol (C5H11OH) were used as analytical layers with 3 µm. The sensor serves as a theoretical foundation for experimental research. The blood plasma had the highest sensitivity with a sensitivity of 10,638.297 nm/RIU and a resolution of 9.410-6RIU. The proposed sensor is a promising candidate for a low-cost, simple-geometry biochemical sensing solution.

The construction of a heat exchange element based on a matrix of silicon whiskers for thermal stabilization systems of miniature heat sources with specific power up to 100 W/cm2 operating over a wide range of ambient temperatures is proposed. Based on the developed mathematical model of convective heat transfer in a microchannel compact heat exchanger with a developed heat exchange surface, numerical simulation of the hydrodynamics and heat transfer processes for various configurations of microchannel insertions was carried out. Fields of pressures, flow velocities, coolant temperatures and matrix from silicon single crystals have been obtained in a wide range of coolant flow rates, criteria dependencies for the Nusselt number and pressure losses of various geometric configurations of heat exchangers have been determined. Critical operation modes are investigated; optimization directions are proposed. According to the developed technology, prototypes for testing have been manufactured.

In this work, the cuprous oxide (Cu2O) thin film on glass substrates were fabricated at low growth temperature by a single-step aqueous solution of chemical bath deposition method. In order to optimize optical and morphology quality, the effect of two different heat treatment methods are conventional furnace annealing process and continuous wave (CW) CO2 laser annealing technique were investigated. The effect of annealing temperatures on the properties of Cu2O thin films were systematically investigated by UV-Vis spectrophotometer, X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM).

The behaviors of yttrium aluminum garnet (YAG) phosphor powder doped by cerium (YAG:Ce3+) was studied. Here, the YAG:Ce3+ nanopowders have been synthesized using microwave combustion (MW) according to the formula, Y(3-0.04) Al5O12: 0.04Ce3+ to produce white light emitting diode (WLEDs) by conversion from blue indium gallium nitride light emitting diode (InGaN LED, 445 nm) chips; the whole process took only 20 min. Pure YAG phase was obtained after annealing at 1050 °C for 5 h with nonaggregated and spherical particles. Thermogravimetry and derivative thermogravimetry (TG/DTG), X-ray powder diffraction (XRPD), transmission electron microscope (TEM), photoluminescence (PL), electroluminescence (EL) emissions and standard CIE 1931 chromaticity diagrams have been used to characterize the samples. The highest WLEDs emission was achieved for the annealed YAG:Ce3+, together with proper color rendering index (CRI), and tunable correlated color temperature (CCT). Finally, we conclude that the decreasing EL intensity at increased injection current is caused by the thermal ionization from the 5d1 level to the conduction band.

This study involves synthesizing gallium nitride (GaN) nanoparticles (NPs) under six different ablation energies using the pulsed laser ablation method. The nanoparticle was deposited using drop cast method on a quartz substrate. XRD pattern shows two peaks of h-GaN nanoparticles at 2θ = 34.64 and 37.98, reflected from (002) and (100) planes. The morphological properties indicate the hexagonal crystal nature of GaN that shows in the XRD pattern. Photoluminescence (PL) spectra show the highest laser power, 2000 mj has a minor emission peaked at 3.34 eV. The maximum emission peak 3.83 eV at 1400 mJ. The study depends on the pulsed laser to generate nanoparticles with different characteristics.

Recently, Cu2ZnSnS4 (CZTS) chalcogenide has been given extra attention in CZTS thin-film solar cells. In order to enhance the conversion efficiency of CZTS thin-film solar cells, the physical properties of CZTS semiconductor have been improved by incorporating Cr elements into the CZTS semiconductor using the solvothermal method. The experimental results showed that the Cr[Formula: see text] ion had stronger hybridization and are more effective on energy storage than Zn[Formula: see text] ion. XRD pattern revealed that the crystal structure of CCrTS compound has high crystallinity and low distortion. Raman analysis indicated the structural transition from kesterite CZTS to stannite CCrTS occurred in the multicomponent CZCrTS samples with Cr content ([Formula: see text]) in the range of 0.75–1. In addition, VSM and UV–Vis absorption spectrum showed the CCrTS compound had a new opto-magnetic property and exhibit a strong ferromagnetic ordering at room temperature. Where the magnetic energy resulted from incorporating Cr[Formula: see text] ion in the Cu2ZnSnS4 has been stored and distributed in abroad absorption band in UV–vis ranges And Also, led to a decrease in the direct bandgap in the ranges of 1.54–1.25[Formula: see text]eV. FE-SEM showed that by replacing Cr[Formula: see text] ion with Zn[Formula: see text] ion, the particle size was decreased as a result of converting the applied strain from compressive strain to tensile strain in the CZCr[Formula: see text]TS resulting in decreasing the unit cell volume and the crystal size. This shows that incorporating Cr[Formula: see text] ions into CZTS compound may be well suitable for fabricating it as an absorber layer in CZTS thin-film solar cells.

The zinc (II) complex supported on magnetic nanoparticles Fe3O4 as a novel and efficient magnetically recoverable catalyst (Fe3O4-Phenanthroline-Zn) was designed and characterized using the most common spectroscopic techniques including FT-IR spectroscopy, SEM, TEM, EDX, XRD, VSM, and ICP-OES. The Fe3O4-Phenantroline-Zn catalyst is shown to be efficient for the multicomponent synthesis of heterocycles including highly substituted piperidines and pyrano[2,3-d]pyrimidines. This system has many advantages, such as excellent level of reusability of magnetic catalysts, high yields, simplicity of separation of catalysts using an external magnet, environmental benignity and ease of handling. To the best of our knowledge, it is the first report on the utilization of zinc nanomagnetic catalyst for the multicomponent synthesis of highly substituted piperidines.

In this article, structural and textural defects of LiNbO 3 waveguide are investigated using SEM imaging technology. The outcomes show that maximum power transfer can be maintained with a crack-free edges of the optical waveguide.

LiNbO3 optical waveguide is prepared at different wavelengths to investigate and measure the propagation loss and the efficiency. The results show that high efficiency is maintained at a stirring time of 48 hours at 630nm.

In this part, the process of preparing LiNbO3 in the laboratory is defined. The morphological analysis showed that a particle size of the deposited nanomaterials could be found in the range of 30-130nm.

In this article, a high-quality LiNbO3 thin film i s p repared u nder different stirrer times using Sol – Gel method. The results show that the longer the time the samples annealed, the thicker sample is obtained.

Cerium-doped transparent Y3Al5O12 (YAG:Ce3+) is the most widely used phosphor for converting blue to white light in light-emitting diodes (LEDs). Here, YAG:Ce3+ powders were synthesised through microwave-assisted combustion by using organic fuel urea. In YAG system applications, the powder structure and properties play key roles in the performance of terms of white LEDs (WLEDs). Accordingly, this study aimed to determine the effects of thermal treatment and Ce3+ concentration on the structure, morphology, chemical composition and luminescence properties of YAG powders. A direct conversion from the monoclinic and hexagonal phases to the cubic one was achieved at >850 °C. This conversion was accompanied by increased particle size in the range of 50–100 nm and decreased lattice strain. However, powder sintering at high temperature was required to incorporate Ce3+ into the YAG matrix and eliminate residual impurity phases. The highest electroluminescence (EL) emission was achieved for the sintered powders at 1050 °C with low dopant concentration (2.0 mol%), offering daylight WLED with a correlated colour temperature of 6834 K and corresponding colour-rendering index of 68.2. Finally, a slightly decreased intensity and red-shift in the EL peak position were observed. These findings were attributed to the presence of a separated CeO2 cubic phase (Ce4+) and concentration quenching for YAG ceramics with >2.0 mol% cerium content.

Here, we report the seed/catalyst-free growth of 2D and 3D ZnO nanostructures on a glass substrate by thermal evaporation of Zn powder in the presence of O2 gas. These nanostructures were grown on (75 ± 5 nm) ZnO seed layers, which were deposited on glass substrates by radio frequency magnetron sputtering. Prior to synthesized ZnO nanostructures, the sputtered ZnO seeds were annealed using the continuous wave CO2 laser at 450 ℃ in air for 15 min.The effects of carrier gas flow rate on the morphological, structural, and optical properties were systematically studied using field emission scanning electron microscopy, X-ray diffraction and UV-Vis spectroscopy.

A seed layer-assisted chemical bath deposition (SCBD) method at low temperature has been developed to growth uniform and high crystal quality cuprous oxide (Cu2O) nanoparticles on transparent conductive/glass substrates. These films were grown on indium-doped tin oxide (ITO) as seed layer which deposited on glass substrates using magnetron sputtering-RF . The ITO seed annealing process by continuous beam (CW) of CO2 laser was used prior to growing the Cu2O nanoparticles. In this study, controlled synthesis of Cu2O films were investigated by controlling the growth temperature at 55, 60, 65, and 70 oC, respectively. The products of films were characterized in detail by using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD). Optical properties of this Cu2O nanoparticles were examined UV-Vis spectroscopy. The study suggests synthesis route for developing high quality Cu2O nanoparticles using SCBD method for optical and electronic applications.

In this study, one-dimensional (1D) zinc oxide (ZnO) nanoneedles are successfully fabricated on a Ag catalyst-coated glass substrate through simple physical vapor deposition via thermal evaporation of zinc (Zn) powder in the presence of oxygen (O2) gas at a low growth temperature of 450°C. The growth rate and diameter of ZnO nanoneedles increase as a function of varying silver (Ag) film thicknesses and argon (Ar) flow rates. Detailed structural investigations confirm that the synthesized nanoneedles have high crystallinity with a hexagonal wurtzite structure, and they preferentially grow along the c-axis orientation. This approach provides a simple and cost-effective method for the synthesis and controlled growth of 1D nanostructures, which can be useful in solid-state devices and various optoelectronic applications.

Catalyst-free growth of ZnO nanostructures were synthesized on ZnO seed layers with different thickness (25–150 nm) coated glass substrates by thermal evaporation method. Prior to the growth process, the sputtered ZnO seed layers were annealed using the continuous wave CO2 laser as a heat source at 450 °C in air for 15 min. The fabrication and characterization of a metal–semiconductor–metal ultraviolet photodetectors based on ZnO nanostructures with different thickness of seed layer were successfully fabricated. Upon exposure to 365 nm light (1.5 mW/cm2) at five-bias voltage, the device with 100 nm thick seed layer showed a relatively high UV sensitivity, quick response, and high responsivity. The prototype device shows a cost effective glass substrate using thermal evaporation method for ZnO nanostructures synthesis and demonstrates the possibility of constructing nanoscale photodetectors for nano-optics applications.

Yttrium and aluminium nitrate phosphors doped with cerium nitrate and mixed with urea (fuel) are prepared by using microwave-induced combustion synthesis according to the formula Y(3–0.06)Al5O12:0.06Ce3+ (YAG:Ce3+) to produce white light emitting diodes by conversion from blue indium gallium nitride-light emitting diode chips. The sintering time with fixed temperature (1050°C) for phosphor powder was optimized and found to be 5 h. The crystallinity, structure, chemical composition, luminescent properties with varying currents densities and chromaticity were characterized by x-ray diffraction, field emission-scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, photoluminescence emission, electroluminescence and standard CIE 1931 chromaticity diagram, respectively. The energy levels of Ce3+ in YAG were discussed based on its absorption and excitation spectra. The results show that the obtained YAG:Ce3+ phosphor sintered for 5 h has good crystallinity with pure phase, low agglomerate with spherical shaped particles and strong yellow emission, offering cool-white LED with tuneable correlated color temperature and a good color rendering index compared to those prepared by sintering for 2 h and as-prepared phosphor powders.

White light emission from blue light-emitting diodes (blue-LED) was generated using phosphor. Yttrium nitrate and aluminum nitrate phosphor doped with cerium nitrate (activator) and mixed with urea (fuel) were synthesized by a novel technique that uses continuous wave–CO2 laser-induced solution combustion synthesis (LISCS, 40 W). The annealing temperature to enhance crystallinity of particles at 1050 °C was achieved for 5 h. The crystallinity, structure, chemical composition, electroluminescence properties, and chromaticity of the powder phosphor samples with the composition Y(3−x) Al5O12:xCe3+ (x = 0.04) are reported in this study. All samples were investigated using Brunauer–Emmett–Teller method, X-ray diffraction, field emission-scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, electroluminescence and standard CIE 1931 chromaticity analysis. By controlling the composition and chemical structure of Y2.96Al5O12:0.04Ce3+ (YAG:Ce+3) mixed with epoxy, white light with a broadband luminescence spectrum, high color rendering index, and tunable correlated color temperature exhibits and offer cool white LED. Results reveal that the phosphor prepared using the novel technique (such as LISCS) produces excellent crystal phase and morphology, as well as better luminescence properties than the phosphor synthesized by using the traditional microwave technique.

We report the growth mechanism of ZnO nanowire balls by thermal evaporation under intermittently pumped carrier gas as a new and simple nucleation method. The structural, morphological, and optical properties of the nanowires were analyzed by field emission scanning electron microscopy, X-ray diffraction, UV–vis spectroscopy, and photoluminescence spectroscopy. Results showed that the proposed method facilitates epitaxial nucleation and growth of high density vertically aligned ZnO nanowires with length of several micrometers and that have a smaller diameter compared to that of ZnO nanowires fabricated by traditional continuous pumping described in the literature under the same growth condition. These findings suggest that the use of intermittently pumped carrier gas is one of effective control parameters that promote the nucleation and growth of nanomaterials using thermal evaporation method.

Novel one-dimensional single-crystalline ZnO nanorod and nanoneedle arrays on a Cu catalyst layer-coated glass substrate were investigated via a simple physical vapor-deposition method by thermal evaporation of Zn powder in the presence of O 2 gas. The ZnO nanorods and nanoneedles were synthesized along the c-axis growth direction of the hexagonal crystal structure. The diameter and growth rate of the high-quality and well-oriented one-dimensional ZnO nanostructures is achieved as a function of varying growth temperature and growth time. This study serves as the basis for further research on the growth of 1D ZnO nanostructures on a cost-effective glass substrate and at low temperature.

We report the catalyst-free growth of various morphologies of three-dimensional ZnO tetrapods on glass substrate by thermal evaporation of Zn powder in the presence of O 2 gas. In this study, controllable synthesis of tetrapods was achieved through two independent temperature regions: 650–425 °C and 750–475 °C. The effects of the growth temperature on the structural, morphological, and optical properties of tetrapods were systematically studied using field emission scanning electron microscopy, X-ray diffraction, UV–vis spectroscopy, and photoluminescence spectroscopy. In the presence of junctions (needle–wire junctions), the optimal sample of ZnO tetrapods-based metal-semiconductor-metal UV detector was fabricated. Upon exposure to 365 nm light (0.22 mW/cm 2 ) at five-bias voltage, the device exhibited a high sensitivity of 15.22 × 10 3 with a low dark current. In addition, the internal photoconductive gain was 153.2, and the photoresponse peak was 917 mA/W. Furthermore, the response and recovery times were 1.1 and 0.59 s, respectively. This new approach provides a cost effective substrate and simple method to control the synthesis of tetrapods and demonstrates the possibility of constructing nanoscale photodetectors for nano-optics applications.

Here, we report for the first time the fabrication of metal–semiconductor–metal ultraviolet photodetector based on catalyst-free growth of ZnO nanowire networks on ITO seeds/glass substrates by thermal evaporation method. The morphological, structural, and optical properties of the sample were studied by using field emission scanning electron microscopy, X-ray diffraction, photoluminescence, and UV–Vis spectrophotometer. Upon exposure to 365 nm light (1.5 mW/cm2) at five-bias voltage, the device showed 2.32 × 103 sensitivity. In addition, the photocurrent was 1.79 × 10−4 A, and the internal gain of the photodetector was 24.2. The response and the recovery times were calculated to be 3.9 and 2.6 s, respectively, upon illumination to a pulse UV light (365 nm, 1.5 mW/cm2) at five-bias voltage. All of these results demonstrate that this high-quality detector can be a promising candidate as a low-cost UV photodetector for commercially integrated photoelectronic applications.

Novel three-step directions of glass substrate for catalyst-free growth of ZnO tetrapods (ZnO-Ts) without using catalyst or seed layer via thermal evaporation method were investigated. In this study, controlled synthesis of ZnO-Ts was achieved through glancing angle deposition by three-step directions of glass substrate with inclination angles of 0°, 45°, and 90° toward the gas flow at a growth temperature of 650 °C. The effects of substrate inclination angles on the morphological, structural, and optical properties were systematically investigated using field emission scanning electron microscopy, X-ray diffraction, UV–vis spectroscopy, and photoluminescence spectrum. Results showed that the substrate tilt angle is one of the most critical control parameters in determining the nucleation and growth of ZnO-Ts. This new approach provides a cost-effective and simple method for the synthesis of tetrapods, which can be useful in various optoelectronic applications and solid-state devices.

Here, we report for the first time the catalyst-free growth of large-scale uniform shape and size ZnO tetrapods on a glass substrate via thermal evaporation method. Three-dimensional networks of ZnO tetrapods have needle–wire junctions, an average leg length of 2.1–2.6 μm, and a diameter of 35–240 nm. The morphology and structure of ZnO tetrapods were investigated by controlling the preparation temperature of each of the Zn powder and the glass substrate under O2 and Ar gases. Studies were carried out on ZnO tetrapods using X-ray diffraction, field emission scanning electron microscopy, UV–vis spectrophotometer, and a photoluminescence. The results showed that the sample grow in the hexagonal wurtzite structure with preferentially oriented along (002) direction, good crystallinity and high transmittance. The band gap value is about 3.27 eV. Photoluminescence spectrum exhibits a very sharp peak at 378 nm and a weak broad green emission.

Novel catalyst-free growth of ZnO nanowires (ZnO-NWs) on ITO seeds/glass substrate by thermal evaporation method, and effects of continuous wave CO2 laser thermal annealed seed layer on the morphology and properties of ZnO-NWs growth were investigated. The effects of sputtered ITO seed layer laser annealing temperature on the morphological, structural, and optical properties of ZnO-NWs was systematically investigated at temperatures 250, 350, and 450 °C, respectively. The surface morphology and structure of the seeds and the products of ZnO-NWs were characterized in detail by using field emission scanning electron microscopy, atomic force microscopy, and X-ray diffraction. Optical properties were further examined through photoluminescence, and UV–Vis spectrophotometer. A growth mechanism was proposed on the basis of obtained results. The results showed that the nanowires were strongly dependent on the seed layer annealing temperatures, which played an important role in nucleation and dissimilar growth of the nanowires with varying sizes and geometric shapes.