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In Situ SiO <sub/>2</sub> Passivation of Epitaxial (100) and (110)InGaAs by Exploiting TaSiO <sub/><i>x</i> </sub> Atomic Layer Deposition Process
摘要： In this work, an in situ SiO2 passivation technique using atomic layer deposition (ALD) during the growth of gate dielectric TaSiOx on solid-source molecular beam epitaxy grown (100)InxGa1?xAs and (110)InxGa1?xAs on InP substrates is reported. X-ray reciprocal space mapping demonstrated quasi-lattice matched InxGa1?xAs epitaxy on crystallographically oriented InP substrates. Cross-sectional transmission electron microscopy revealed sharp heterointerfaces between ALD TaSiOx and (100) and (110)InxGa1?xAs epilayers, wherein the presence of a consistent growth of an ～0.8 nm intentionally formed SiO2 interfacial passivating layer (IPL) is also observed on each of (100) and (110)InxGa1?xAs. X-ray photoelectron spectroscopy (XPS) revealed the incorporation of SiO2 in the composite TaSiOx, and valence band offset (ΔEV) values for TaSiOx relative to (100) and (110)InxGa1?xAs orientations of 2.52 ± 0.05 and 2.65 ± 0.05 eV, respectively, were extracted. The conduction band offset (ΔEC) was calculated to be 1.3 ± 0.1 eV for (100)InxGa1?xAs and 1.43 ± 0.1 eV for (110)InxGa1?xAs, using TaSiOx band gap values of 4.60 and 4.82 eV, respectively, determined from the fitted O 1s XPS loss spectra, and the literature-reported composition-dependent InxGa1?xAs band gap. The in situ passivation of InxGa1?xAs using SiO2 IPL during ALD of TaSiOx and the relatively large ΔEV and ΔEC values reported in this work are expected to aid in the future development of thermodynamically stable high-κ gate dielectrics on InxGa1?xAs with reduced gate leakage, particularly under low-power device operation.
关键词： in situ SiO2 passivation,atomic layer deposition,InxGa1?xAs,band alignment,TaSiOx,gate dielectric
更新于2025-09-23 15:21:01
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Peculiarities of using nanomaterials based on SiO <sub/>2</sub> -SnO <sub/>2-</sub> In <sub/>2</sub> O <sub/>3</sub> as sensitive elements of vacuum sensors
摘要： Experimental data on the use of nanomaterials based on SiO2-SnO2-In2O3 as sensitive elements of vacuum sensors are presented. It is shown that the sensory response of a three-component system under consideration is determined by the mass fraction of indium oxide. It was determined that depending on the content of In2O3 the nanomaterials under study can be characterized by a decrease and an increase in resistance when the pressure is reduced lower than atmospheric one. The mechanisms that potentially correspond to the observed phenomenon are considered.
关键词： nanomaterials,indium oxide,SiO2-SnO2-In2O3,vacuum sensors,sensitive elements
更新于2025-09-23 15:21:01
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Ethanol–water-assisted room temperature synthesis of CsPbBr3/SiO2 nanocomposites with high stability in ethanol
摘要： All-inorganic halide perovskites have attracted great attention by virtue of the merits of bright emission, tunable wavelength and narrow-band emission. Despite the excellent optical features, all-inorganic halide perovskite materials have suffered from intrinsic instability, which has limited their applications in various optoelectronic devices. To mitigate the intractable issue, we demonstrated the CsPbBr3 nanoparticles decorated with smaller SiO2 nanocrystals to passivate the surface defects; SiO2 nanoparticles were applied as a barrier layer to maintain the optical property and enhance environmental stability. A facile in situ method was proposed to prepare CsPbBr3/SiO2 nanocomposites, in which an environmental ethanol/water solvent system was needed with the addition of tetraethyl orthosilicate (TEOS) as a silicon precursor. The obtained CsPbBr3/SiO2 nanocomposites have better optical characteristic and stability than bare CsPbBr3 nanoparticles. Even 70% photoluminescence intensity of as-prepared CsPbBr3/SiO2 nanocomposites can be maintained after 168 h storage in ethanol. This newly developed synthesis will open up a new route for the fabrication of optoelectronic devices in an environmentally friendly way, and the as-obtained perovskite materials with improved stability will make them great potential for multifunctional optoelectronic devices.
关键词： Ethanol–water-assisted room temperature synthesis,All-inorganic halide perovskites,High stability,CsPbBr3/SiO2 nanocomposites,Optoelectronic devices
更新于2025-09-23 15:21:01
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Large-scale preparation of rice-husk-derived mesoporous SiO2@TiO2 as efficient and promising photocatalysts for organic contaminants degradation
摘要： Mesoporous SiO2@TiO2 photocatalysts with application prospect for organic contaminants degradation were prepared by utilizing rice husk (RH), an easy-available bioresource, as the biotemplate. Structures and physicochemical properties of RH-derived SiO2@TiO2 photocatalysts were systematically characterized and discussed. Results indicate the RH-derived mesoporous and thermal-stable template, which can postpone the anatase-rutile phase transition of TiO2 at high temperatures, is mainly consisted of tightly compacted amorphous SiO2 nanoparticles. Optimized calcination temperature of 700 °C is positive for preparing the most active RH-derived SiO2@TiO2, which has the anatase phase, mesoporous structure, proper crystalline degree (grain size of 22.75 nm), specific surface area of 41.13 m2/g, and high ability in separating the photogenerated electron-hole pairs, for removal of Rhodamine B (RhB) in aqueous solutions under both the xenon lamp and visible light irradiation. Moreover, large-scale preparation, stable, and recyclable properties of the photocatalysts are also confirmed, which makes them as promising photocatalysts for practical application.
关键词： SiO2@TiO2 mesoporous structure,Biotemplate,Rice husk,Photocatalysis,Practical application
更新于2025-09-23 15:21:01
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Plasmonic Enhanced Gold Nanoclusters-Based Photoelectrochemical Biosensor for Sensitive Alkaline Phosphatase Activity Analysis
摘要： Low-toxicity gold nanoclusters-decorated Ag@SiO2 (Au NCs-Ag@SiO2) nanocomposites modified plasmonic photoelectrodes were firstly fabricated to improve the photoelectric properties of Au NCs and practical application in biological detection. Through adjusting distance between Au NCs and plasmonic silver nanoparticles (Ag NPs), the photocurrent intensity of Au NCs enhanced by 3.8 times attributed to strong competition between enhancement functions of hot electron transfer, local electric field, light scattering effects and quenching functions of nonradiative energy transfer. Further comparison between experimental results and theoretical simulations were conducted to gain a deeper understanding toward the photoelectric enhancement mechanism. Moreover, Au NCs-Ag@SiO2 nanocomposites was successfully applied to the construction of photoelectrochemical (PEC) biosensors for sensitively detecting alkaline phosphatase activity. This proposed PEC biosensor showed a wide linear range from 0.04 to 400 U·L-1, and a low detection limit of 0.022 U·L-1.
关键词： Alkaline phosphatase,Gold nanoclusters,Photoelectrochemical,Ag@SiO2
更新于2025-09-23 15:19:57
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Plasmonic Enhancement of Dye Fluorescence in Polymer/Metal Nanocomposites
摘要： The effect of the plasmonic enhancement of dye fluorescence in poly(vinyl butyral) films containing Ag/SiO2 core-shell nanoparticles has been thoroughly studied. It has been shown that the magnitude of this effect can be quite large (up to 5 times) even for a dye having a very high quantum yield (coumarin 7). Therewith, it substantially depends on the size and concentration of Ag/SiO2 particles and the quantum yield of a dye. The results obtained are discussed with involvement of mechanisms reported in the literature for plasmonic enhancement of fluorescence of dyes characterized by high and low quantum yields.
关键词： plasmonic enhancement,dye fluorescence,quantum yield,polymer/metal nanocomposites,Ag/SiO2 core-shell nanoparticles
更新于2025-09-23 15:19:57
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Synergetic adsorption and photo-Fenton degradation of methylene blue by ZnFe <sub/>2</sub> O <sub/>4</sub> /SiO <sub/>2</sub> magnetic double-mesoporous-shelled hollow spheres
摘要： Adsorption and Fenton technologies have been widely employed to deal with wastewater. ZnFe2O4/SiO2 magnetic double-mesoporous-shelled hollow spheres (MDSHSs) were feasibly synthesized by a solvothermal method. The as-synthesized MDSHSs show excellent adsorption and selectivity for methylene blue (MB), which it took about only 1 min to reach the adsorption equilibrium. About 50% MB was removed by adsorption, and other 50% MB was degraded under further photo-Fenton process. Effects of experimental conditions on the adsorption and photo-Fenton process were investigated. The mechanisms of MDSHSs formation and photo-Fenton process were proposed. Total organic carbon (TOC) reduction reached as high as 90% with 60 mg/L of MB for 90 min. The experimental results indicated that MDSHSs exhibit a remarkable adsorption and catalytic activity for photo-Fenton process in a wide pH range of 3.3–11.0. Simultaneously, the composite shows an excellent stability and reusability.
关键词： photo-Fenton,magnetic property,porous materials,ZnFe2O4/SiO2,adsorption
更新于2025-09-23 15:19:57
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Refractory plasmonics enabling 20% efficient lead-free perovskite solar cells
摘要： Core-shell refractory plasmonic nanoparticles are used as excellent nanoantennas to improve the efficiency of lead-free perovskite solar cells (PSCs). SiO2 is used as the shell coating due to its high refractive index and low extinction coefficient, enabling the control over the sunlight directivity. An optoelectronic model is developed using 3D finite element method (FEM) as implemented in COMSOL Multiphysics to calculate the optical and electrical parameters of plain and ZrN/SiO2-modified PSCs. For a fair comparison, ZrN-decorated PSCs are also simulated. While the decoration with ZrN nanoparticles boosts the power conversion efficiency (PCE) of the PSC from 12.9% to 17%, the use of ZrN/SiO2 core/shell nanoparticles shows an unprecedented enhancement in the PCE to reach 20%. The enhancement in the PCE is discussed in details.
关键词： lead-free perovskite solar cells,refractory plasmonics,ZrN/SiO2 core/shell nanoparticles,power conversion efficiency,optoelectronic modeling
更新于2025-09-23 15:19:57
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Ion Implantation - Research and Application || MeV Electron Irradiation of Ion-Implanted Si-SiO2 Structures
摘要： The effect of (10–25) MeV electron irradiation on Si‐SiO2 structures implanted with different ions (Ar, Si, O, B, and P) has been investigated by different methods, such as deep‐level transient spectroscopy (DLTS), thermo‐stimulated current (TSCM), Rutherford backscattering (RBS), and soft X‐ray emission spectroscopy (SXES). It has been shown that in double‐treated Si‐SiO2 structures, the defect generation by high‐energy electrons depends significantly on the location of preliminary implanted ions relative to the Si‐SiO2 interface as well as on the type (n‐ or p‐Si) of silicon wafer. SiO2 surface roughness changes, induced by ion implantation and high‐energy electron irradiation of Si‐SiO2 structures, are observed by the atomic force microscopy (AFM). Si nanoclusters in SiO2 of ion‐implanted Si‐SiO2 structures generated by MeV electron irradiation is also discussed.
关键词： ion implantation,Si nanoclusters,MeV electron irradiation,Si‐SiO2 structures,radiation defects
更新于2025-09-23 15:19:57
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Structural and optical properties of doped ZnO/SiO <sub/>2</sub> nanocomposite
摘要： The synthesis of ZnO/SiO2 nanocomposite doped with Co, Cu and Mn nanoparticles were performed using sol-gel method. Rietveld refinement analysis was done for the X-ray diffraction data and results showed that all samples are single wurtzite hexagonal phase and have an average crystallite size ~14 nm. The lattice parameters, bond length, crystallite size, microstrain, dislocation density and the system volume were studied in details. Transmission electron microscopy technique showed that nanoparticles characterized by an elliptical shape. Fourier transform infrared and scanning electron microscope techniques proved the presence of SiO2 in the system. The energy gap values of both undoped and doped samples with Co, Mn and Cu were 2.84, 2.47, 2.71 and 2.8 eV, respectively. Photoluminescence spectra for undoped and doped ZnO/SiO2 were investigated in details.
关键词： ZnO/SiO2,Sol-gel,Nanocomposites,Structure,Photoluminescence
更新于2025-09-23 15:19:57