Search Results (62)

Fogging on glass poses a severe challenge in daily life, potentially even becoming life-threatening during driving and surgery; therefore there is a need for antifog surface structures. Fabricating superhydrophilic surfaces has been one of the major solutions to the challenge. Conventional direct thermal annealing glass in a furnace at 900 K for 2 h led to superhydrophicity but failed to produce superhydrophilicity on quartz. Meanwhile, it degraded transmission and was low throughput. This study developed a programmed fast plasma treatment of planar soda-lime glass and quartz in air, applied for only a few seconds, that was able to fabricate superhydrophilic surfaces. The process led to a 0° contact angle without sacrificing transmission, a result unreported before. The plasma treatment covered a whole 30 × 30 cm² substrate in only approximately 5 s, resulting in superhydrophilicity, which has rarely been reported before. This simple yet controllable process has great potential for further scale-up and practical applications. Full article

Micro-Electro-Mechanical System (MEMS) technology is employed to fabricate surface acoustic wave (SAW)-type and resistive-type ozone sensors on quartz glass (SiO₂) substrates. The fabrication process commences by using a photolithography technique to define interdigitated electrodes (IDEs) on the substrates. Electron-beam evaporation (EBE) followed by radio frequency (RF) magnetron sputtering is then used to deposit platinum (Pt) and chromium (Cr) electrode layers as well as a zinc oxide (ZnO) sensing layer, respectively. Finally, annealing is performed to improve the crystallinity and sensing performance of the ZnO films. The experimental results reveal that the ZnO thin films provide an excellent ozone-concentration sensing capability in both sensors. The SAW-type sensor demonstrates a peak sensitivity at a frequency of 200 kHz, with a rapid response time of just 35 s. Thus, it is suitable for applications requiring a quick response and high sensitivity, such as real-time monitoring and high-precision environmental detection. The resistive-type sensor shows optimal sensitivity at a relatively low operating temperature of 180 °C, but has a longer response time of approximately 103 s. Therefore, it is better suited for low-cost and large-scale applications such as industrial-gas-concentration monitoring. Full article

In this work, the influence of Ba/Ca ratios on the BaO-CaO-SiO₂ (BCS) glass network structure, crystallization phases, and coefficient of thermal expansion (CTE) was investigated. As the Ba/Ca ratio increases, the Qⁿ units in the glass network structure have undergone significant changes. The Q⁴ units in the BCS glass network transform into Q³ units, indicating the reduction of the glass network connectivity. The variation in the Ba/Ca ratio leads to a change in the crystallization phases of BCS glass-ceramics sintered at a temperature higher than Tc (crystallization temperature). The addition of α-SiO₂ (quartz) could regulate the crystallization phases and their ratio of the barium silicates (BaSi₂O₅, Ba₂Si₃O₈, and Ba₅Si₈O₂₁) in the BCS glass-ceramics. An abundant orthorhombic BaSi₂O₅ phase can be obtained in the BCS glass-ceramics with 15 wt% α-SiO₂ calcinated over 875 °C. The α-SiO₂ modified BCS glass-ceramics exhibited excellent properties (CTE = 12.10 ppm/°C, ε_r = 7.49 @ 13.4 GHz, tanδ = 4.96 × 10⁻⁴, Q × f = 27,034 GHz) sintered at optimized conditions, making it a promising candidate material for RF module and electronic packaging substrate. Full article

In this research, Hall effect experiments and optical fittings were mainly conducted to elucidate the effect of hydrogen annealing on the electronic properties of polycrystalline Al-doped Zinc Oxide thin films by distinguishing the scattering by ion impurities and the scattering by grain boundaries. By comparing the carrier density and those mobilities of H₂-annealed samples with Ar-annealed samples, the effect of H₂ annealing was highlighted. AZO thin films were prepared on the quartz glass substrate at R.T. by an RF magnetron sputtering method, and the carrier density was controlled by changing the number of Al chips on the Zn target. After fabricating them, they were post-annealed in hydrogen or argon gas. Optical fitting was based on the Drude model using the experimental data of Near-Infrared spectroscopy, and the mobility at grain boundaries was analyzed by Seto’s theory. Other optical and crystalline properties were also checked by SEM, EDX, XRD and profilometer. It is indicated that the H₂ annealing would improve both carrier density and mobility. The analysis referring to Seto’s theory implied that the improvement of mobility was caused by the carrier generation from introduced hydrogen atoms both at the grain boundary and its intragrain region. Furthermore, the effect of H₂ annealing is relatively pronounced especially in low-doped region, which implies that Al and H have some interaction in AZO thin film. The interaction between Al and H in AZO thin film is still not confirmed, but this result implied that this interaction negatively affects the mobility at grain boundary. Full article

Lanthanum oxide (La₂O₃) layers are widely used in electronics, optics, and optoelectronics due to their properties. Lanthanum oxide is also used as a dopant, modifying and improving the properties of other materials in the form of layers, as well as having a large volume. In this work, lanthanum oxide layers were obtained using MOCVD (Metalorganic Chemical Vapor Deposition) on the inner walls of tubular substrates at 600–750 °C. The basic reactant was La(tmhd)₃ (tris(2,2,6,6-tetramethyl-3,5-heptanedionato)lanthanum(III)). The evaporation temperature of La(tmhd)₃ amounted to 170–200 °C. Pure argon (99.9999%) and air were used as the carrier gases. The air was also intended to remove the carbon from the synthesized layers. Tubes of quartz glass were used as the substrates. La₂O₃ layers were found to be growing on their inner surfaces. The value of the extended Gr_x/Re_x² criterion, where Gr—Grashof’s number, Re—Reynolds’ number, x—the distance from the gas inflow point, was below 0.01. The microstructure of the deposited layers of lanthanum oxide was investigated using an electron scanning microscope (SEM). Their chemical composition was analyzed via energy-dispersive X-ray (EDS) analysis. Their phase composition was tested via X-ray diffraction. The transmittance of the layers of lanthanum oxide was determined with the use of UV-Vis spectroscopy. The obtained layers of lanthanum oxide were characterized by a nanocrystalline microstructure and stable cubic structure. They also exhibited good transparency in both ultraviolet (UV) and visible (Vis) light. Full article

Lead sulfide (PbS) on the nanoscale was synthesized via a chemical route at room temperature using lead nitrate {Pb(NO₃)₂} and sodium sulfide (Na₂S). The Na₂S was prepared at ~105 °C using sodium hydroxide (NaOH) and sulfur (S) powder. The produced PbS, denoted as Lab-PbS, was compared with a high-concentration PbS phase of galena. The produced Na₂S and Lab-PbS were examined using scanning electron microscopy and energy dispersive X-ray spectroscopy for microstructural and chemical analysis. The results confirmed a high-purity PbS compound (>99%) with a nanoscale particle size. The results showed that ultrasonic agitation was vital for obtaining the nanoparticle size of the Lab-PbS. Furthermore, thin films from the synthesized Lab-PbS and galena were successfully thermally evaporated on glass, quartz, and silicon substrates. The formation of nanometric grains was confirmed by scanning electron microscopy (SEM). XRD and FTIR spectroscopy were carried out for the Lab-PbS, galena fine powders, and galena thin films. The average crystal diameter was calculated for the galena thin films and was found to be approximately 26.6 nm. Moreover, the UV–Visible transmission curve was measured for the thin films in the wavelength range of 200–1100 nm in order to calculate the bandgap energy (E_g) for the thin films. The values of E_g were approximately 2.65 eV and 2.85 eV for the galena and Lab-PbS thin films, respectively. Finally, the sintering of the Lab-PbS and galena powders was carried out at ~700 °C for 1 h under vacuum, achieving relative densities of ~98.1% and ~99.2% for the Lab-PbS and galena, respectively. Full article

In this paper, multifunctional, multilevel phase plates of quartz substrate were efficiently prepared by using a newly developed polygon scanner-based femtosecond laser photolithography system combined with inductively coupled discharge plasma reactive-ion etching (ICP-RIE) technology. The femtosecond laser photolithography system can achieve a scanning speed of 5 m/s and a preparation efficiency of 15 cm²/h while ensuring an overlay alignment accuracy of less than 100 nm and a writing resolution of 500 nm. The ICP-RIE technology can control the etching depth error within ±5 nm and the mask-to-mask edge error is less than 1 μm. An 8-level Fresnel lens phase plate with a focal length of 20 mm and an 8-level Fresnel axicon phase plate with a cone angle of 5° were demonstrated. The diffraction efficiency was greater than 93%, and their performance was tested for focusing and glass cutting, respectively. Combined with the high-speed femtosecond laser photolithography system’s infinite field-of-view (IFOV) processing capability, the one-time direct writing preparation of phase plate masks of different sizes was realized on a 6-inch wafer. This is expected to reduce the production cost of quartz substrate diffractive optical elements and promote their customized mass production. Full article

Recently, much research has focused on the search for new mixed donor–acceptor layers for applications in organic electronics. Organic heterostructures with layers based on the generation 1 poly(propylene thiophenoimine) (G1PPT) dendrimer, N,N′-diisopropylnaphthalene diimide (MNDI), and a combination of the two were prepared and their electrical properties were investigated. Single layers of G1PPT and MNDI and a mixed layer (G1PPT:MNDI) were obtained via spin coating on quartz glass, silicon, and glass/ITO substrates, using chloroform as a solvent. The absorption mechanism was investigated, the degree of disorder was estimated, and the emission properties of the layers were highlighted using spectroscopic methods (UV–Vis transmission and photoluminescence). The effects of the concentration and surface topographical particularities on the properties of the layers were analyzed via atomic force microscopy. All of the heterostructures realized with ITO and Au electrodes showed good conduction, with currents of the order of mA. Additionally, the heterostructure with a mixed layer exhibited asymmetry in the current–voltage curve between forward and reverse polarization in the lower range of the applied voltages, which was more significant at increased concentrations and could be correlated with rectifier diode behavior. Consequently, the mixed-layer generation 1 poly(propylene thiophenoimine) dendrimer with N,N′-diisopropylnaphthalene diimide can be considered promising for electronic applications. Full article

The efficiency of thin film photoelectric devices can be improved by redirecting incident electromagnetic radiation along their surface layers. Redirection can be achieved using antireflection coatings made of subwavelength dielectric particle arrays. In this study, we fabricate such coatings, consisting of Ge particles on quartz glass substrates via solid-state dewetting, transforming thin Ge films into compact particles. Using optically transparent substrates, we measure reflection and transmission spectra and determine absorption spectra, showing that substrates coated with Ge particles absorb much more strongly than substrates coated with continuous Ge films. The spectra obtained using objective lenses with different aperture angles indicate that scattered radiation is predominantly directed at glancing angles to the substrate surface. The lateral propagation of scattered radiation is the result of destructive interference, which suppresses both reflected and transmitted radiation. Full article

Glass microlens arrays (MLAs) have tremendous prospects in the fields of optical communication, sensing and high-sensitivity imaging for their excellent optical properties, high mechanical robustness and physicochemical stability. So far, glass MLAs are primarily fabricated using femtosecond laser modification assisted etching, in which the preparation procedure is time-consuming, with each concave-shaped microlens being processed using a femtosecond laser point by point. In this paper, a new method is proposed for implementing large-scale glass MLAs using glass particle sintering with the assistance of ultraviolet (UV) lithography. The glass particles are dispersed into the photoresist at first, and then immobilized as large-scaled micropillar arrays on quartz glass substrate using UV lithographing. Subsequently, the solidified photoresist is debinded and the glass particles are melted by means of sintering. By controlling the sintering conditions, the convex microlens will be self-assembled, attributed to the surface tension of the molten glass particles. Finally, MLAs with different focal lengths (0.12 to 0.2 mm) are successfully fabricated by utilizing different lithography masks. Meanwhile, we also present the optimization of the sintering parameter for eliminating the bubbles in the microlenses. The main factors that affect the focal length of the microlens and the image performance of the MLAs have been studied in detail. Full article

Numerical studies of the waveguide properties of liquid crystal layers bounded by substrates with indium tin oxide (ITO) electrodes using the finite difference time-domain (FDTD) method are carried out. On the basis of the experimental transmittance spectra of ITO-coated glass substrates in the visible and near-infrared ranges, a Lorentz model describing the dielectric properties of the ITO electrodes is created. Then, by numerical modeling, optical systems including a homogeneously aligned LC layer between the thin alignment films and the ITO electrodes on the quartz substrates are studied. It is shown that, in the case of the use of traditional alignment films or their absence, the ITO electrodes lead to significant resonant losses in the waveguide mode for both TE- and TM-polarized light. The losses mechanism based on a phase-synchronized mode coupling occurring in relatively narrow spectral ranges is discussed. We also propose a method to control and exclude the losses using thin alignment films with a proper thickness and low refractive index. Full article

The construction industry is particularly responsible for the appearance of the earth and the environment and for its partial degradation related to climate warming through the production of cement, brick burning, and the processing of substrates for the production of building materials (lime, gypsum, polystyrene, processed materials, etc.). An important aspect of the 21st century has been the overproduction and excessive use of natural resources, including sand. The purpose of this article is to analyze the possibility of using glass sand as a substitute for quartz sand in the production of materials resulting from hydrothermal treatment (so-called silicate bricks). The article is a review of the research conducted since 2016 on laboratory tests on the modification of silicate mass with glass sand from recycled bottle glass, the properties of the mass modified in this way (hydration temperature, consistency, and humidity of the mixture), its physical and mechanical properties, and its structural and potential durability, which is related to, e.g., the direction and degree of crystallization of the C-S-H phase. Tests of compressive strength, density, water absorption, oxide composition (XRF), structure (XRD), microstructure (SEM), and porosity (CT analysis using computer tomography) were carried out. A special point of the research was the use of geochemical modeling code in the form of the GEMS-PSI program in the process of analyzing the modification of silicate mass by glass sand, which is beneficial in limiting ineffective modifications, thus saving time, money, and energy. Studies have shown that the use of glass cullet has a positive effect on the consistency of the modified raw material mass, on the density (1.6–1.75 kg/dm³), and on the compressive strength (15.729–20.3 MPa), while the crystallization of the C-S-H phase occurs in the direction of natrolite and gyrolite, less frequently towards the M-S-H or brucite phase. Full article

The radio frequency (RF) reactive sputtering technique has been used to prepare Zn_1−xNi_xO thin films with 0 ≤ x ≤ 0.08. Composite targets were obtained by mixing and pressing NiO and ZnO powders. Sapphire, quartz and glass were used as substrates. X-ray diffraction analysis of Ni-doped ZnO films indicates that all samples are crystalised in a hexagonal wurtzite structure with a preferred orientation along the (002) plane. Any secondary phase, corresponding to metallic nickel clusters or nickel oxides was not observed. High-resolution transmission electron microscopy (HR-TEM) image observed for Zn_1−xNi_xO thin film shows a strong preferred orientation (texture) of crystalline columns in the direction perpendicular to the substrate surface. Different surface morphology was revealed in AFM images depending on the film composition and growth condition. Optical absorption spectra suggest the substitution of Zn²⁺ ions in the ZnO lattice by Ni²⁺ ions. The energy bandgap value was also found a complex dependence with an increase in Ni dopant concentration. In photoluminescence spectra, two main peaks were revealed, which are ascribed to near band gap emission and vacancy or defect states. Faraday rotation demonstrates its enhancement and growth of ferromagnetism with the increase in Ni content of Zn_1−xNi_xO thin films at room temperature. Full article

Predicting the interfacial thermal resistance (ITR) for various material systems is a time-consuming process. In this study, we applied our previously proposed ITR machine learning models to discover the material systems that satisfy both high transparency and low thermal conductivity. The selected material system of TiO₂/SiO₂ shows a high ITR of 26.56 m²K/GW, which is in good agreement with the predicted value. The nanoscale layered TiO₂/SiO₂ thin films synthesized by sputtering exhibits ultralow thermal conductivity (0.21 W/mK) and high transparency (>90%, 380–800 nm). The reduction of the thermal conductivity is achieved by the high density of the interfaces with a high ITR rather than the change of the intrinsic thermal conductivity. The thermal conductivity of TiO₂ is observed to be 1.56 W/mK with the film thickness in the range of 5–50 nm. Furthermore, the strong substrate dependence is confirmed as the thermal conductivity of the nanoscale layered TiO₂/SiO₂ thin films on quartz glass is three times lower than that on Si. The proposed TiO₂/SiO₂ composites have higher transparency and robustness, good adaptivity to electronics, and lower cost than the current transparent thermal insulating materials such as aerogels and polypropylene. The good agreement of the experimental ITR with the prediction and the low thermal conductivity of the layered thin films promise this strategy has great potential for accelerating the development of transparent thermal insulators. Full article

The aim of this study was to develop a comprehensive technology for the utilization of tailings from quartz vein-hosted gold deposits. We investigated the recovery potential and separation process for gold, feldspar, and quartz from tailings samples collected from the Jinqu gold mine in Henan province, China. The sequence of the principal flowsheet of the comprehensive utilization of gold, feldspar, and quartz from the tailings samples was determined according to the process mineralogy and corresponding experiments. The residual gold in the tailings was extracted, and both feldspar and quartz concentrates were recovered according to the flowsheet of selective desliming, flotation of gold-bearing sulfide ore, removal of iron-containing impurities, flotation separation of feldspar, and purification of quartz. The quartz concentrate met China’s industrial standard for raw-material quartz sand for producing high-grade glass, such as cover glass for touch electronics and TFT LCD liquid crystal substrate glass. The feldspar concentrate also met China’s ceramic industry standards. The established process provides an efficient way for recovering the main valuable minerals in tailings from quartz vein-hosted gold deposits. Moreover, this study demonstrates the synthetic recovery of the same type of gold tailings. Full article