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Rapid synthesis of AlON powders by low temperature solid-state reaction
摘要： High synthesis temperatures and long soaking times are generally required to fabricate AlON powders, which can cause coarsening and aggregation of the powder. Solid-state reaction methods form AlON powders by a direct reaction of Al2O3 and AlN, enabling rapid synthesis of AlON powder at low temperatures. In this work, single phase AlON powders were fabricated by a solid-state reaction method using Al2O3 and AlN powders as raw materials. To lower the synthesis temperature and shorten the soaking time, the raw materials particle sizes and the homogeneity of the Al2O3/AlN mixture were investigated. The effects of AlN content, synthesis temperature, and soaking time on the synthesis of AlON powders were examined. When the AlN content was 27 mol %, single phase AlON powders were synthesized by calcining Al2O3/AlN mixture at 1680 °C for 20 min. After ball-milling at 250 rpm for 24 h, the synthesized AlON powder was ground into a single phase fine AlON powder with an average particle diameter of 320 nm, a narrow size distribution, and good dispersibility. Transparent AlON ceramics with dimensions of Φ100 mm × 1 mm were fabricated by pressureless sintering the produced fine AlON powder.
关键词： B.Grain size,Aluminum oxynitride,A. Powders: solid-state reaction
更新于2025-11-19 16:56:35
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Effects of annealing conditions on the oxygen evolution activity of a BaTaO2N photocatalyst loaded with cobalt species
摘要： Precise engineering of the cocatalyst-photocatalyst interface and optimization of the cocatalyst dispersion are essential for improving the activity of particulate semiconductor photocatalysts. Herein, we report the effects of varying the conditions used to load cobalt oxide (CoOx) as a cocatalyst on the O2 evolution activity of a particulate BaTaO2N photocatalyst, based on trials in an aqueous silver nitrate solution under visible light irradiation. Annealing under an N2 flow after loading the Co species increased the O2 evolution rate threefold compared to that obtained following conventional annealing under an NH3 flow. Subsequent annealing under an H2 atmosphere exposed the BaTaO2N surface as a result of the aggregation of CoOx particles, and further enhanced the photocatalytic O2 evolution by a factor of two, yielding an apparent quantum efficiency of 0.55% at 420 nm. These results indicate the importance of intimate contact between cocatalyst particles and the photocatalyst, as well as the necessity of exposing the photocatalyst surface to make it available for reduction reactions during photocatalytic water oxidation.
关键词： Cocatalyst,Dispersion,Oxynitride,Visible light
更新于2025-11-19 16:51:07
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Thermal atomic layer deposition of AlOxNy thin films for surface passivation of nano-textured flexible silicon
摘要： Aluminum oxynitride (AlOxNy) films with different nitrogen concentration are prepared by thermal atomic layer deposition (ALD) for flexible nano-textured silicon (NT-Si) surface passivation. The AlOxNy films are shown to exhibit a homogeneous nitrogen-doping profile and the presence of an adequate amount of hydrogen, which is investigated by Time-of-Flight Elastic Recoil Detection Analysis (ToF-ERDA). The effective minority carrier lifetimes are measured after the NT-Si surface passivation; the minimum surface recombination velocity (SRV) of 5 cm-s-1 is achieved with the AlOxNy film in comparison to the Al2O3 and AlN films (SRV of 7–9 cm-s-1). The better SRV with AlOxNy film is due to the collective effect of field-effect passivation by the presence of fixed negative charges, and chemical passivation by the presence of hydrogen within the film. The capacitance-voltage, and conductance measurements also are carried out using metal-oxide-semiconductor structure to determine the fixed negative charge density (Nf,ox), and defect density of states (Dit) in the AlOxNy films. The better surface passivation is attributed to unusually large Nf,ox of ~6.07 × 1012 cm-2, and minimal Dit of ~1.01 × 1011 cm-2-eV-1 owing to the saturation of Si dangling bonds by the hydrogen within the AlOxNy film matrix after the annealing step.
关键词： Surface passivation,Time-of-flight elastic recoil detection analysis (ToF-ERDA),Aluminum oxynitride,Thermal atomic layer deposition,Black flexible silicon
更新于2025-10-22 19:40:53
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Hybrid ZnON-Organic Light Emitting Transistors with Low Threshold Voltage <5 V
摘要： The electrical and optical properties of inorganic–organic hybrid light emitting transistors (HLETs) are investigated, which are fabricated using the n-type semiconductor zinc-oxynitride (ZnON) as an electron transporting layer and the poly(p-phenylene vinylene)-based copolymer, Super Yellow (SY), as the light emitting layer. Additionally, the influence of various source (S)–drain (D) electrodes (Al, Ag, and Au) with different work functions (WFs) (4.1, 4.6, and 5.1 eV, respectively) on the performance of HLETs is studied. In order to increase the rate of hole injection from the metal electrodes and increase hole accumulation at the emissive layer, the use of a molybdenum oxide (MoOx) interlayer is also investigated. As a result, optimized devices using MoOx/Au hole injecting electrodes yield high brightness of up to 3.04 × 10^4 cd?m^?2 at a low threshold voltage of 4.79 V. This study provides valuable information about the role of the WF of S–D electrodes in HLETs, which may be exploited to improve the device performance of optoelectronic devices in the future.
关键词： zinc-oxynitride,light emitting transistors,work function,super yellow,low threshold voltage
更新于2025-09-23 15:23:52
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Oxynitride Thin Films versus Particle-Based Photoanodes: a Comparative Study for Photoelectrochemical Solar Water Splitting
摘要： The solar water splitting process assisted by semiconductor photocatalysts attracts growing research interests worldwide for the production of hydrogen as a clean and sustainable energy carrier. Due to their optical and electrical properties several oxynitride materials show great promise for the fabrication of efficient photocatalysts for solar water splitting. This study reports a comparative investigation of particle- and thin films-based photocatalysts using three different oxynitride materials. The absolute comparison of the photoelectrochemical activities favors the particle-based electrodes due to the better absorption properties and larger electrochemical surface area. However, thin films surpass the particle-based photoelectrodes due to their more suitable morphological features that improve the separation and mobility of the photo-generated charge carriers. Our analysis identifies what specific insights into the properties of materials can be achieved with the two complementary approaches.
关键词： Oxynitride,pulsed laser deposition,photoelectrochemistry,thin films,solar water splitting,photoanode
更新于2025-09-23 15:23:52
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Synthesis, characterization and optical property study of BCNO and BCN related nanopowder
摘要： Boron carbon oxynitride (BCNO) and BCN nanocompounds are successfully synthesized by a solid state sintering method using boric acid, urea and dextrose as the sources of B, N and C respectively under inert atmosphere. X-ray diffraction (XRD) and infrared spectroscopy (FTIR) analysis show that nanomaterials are synthesized at the high temperature range of 1350 oC. Sufficient amount of oxygen impurities are present in the sample, which is manifested in their photoluminescence spectra. Increase in temperature to 1350 oC under N2 atmosphere causes elimination of significant amount of O-species from the system. The presence of ample amount of carbon in the system results in the formation of high amount of polycrystalline h-BCN with minor amount of h-BN. However, some residual oxygen in the sample, which is detected in the FTIR study, leads to the formation of BCNO compound. These semiconductor BCNO compounds act as the potential luminescence centers for the blue-green emissions of the particles. Thus, these materials may find potential application as a phosphor material in various opto-electronic devices.
关键词： optical properties,carbon,boron carbon nitride,Boron carbon oxynitride,impurities
更新于2025-09-23 15:22:29
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Synthesis and X-ray absorption spectroscopic analysis of exfoliated perovskite oxynitride nanosheets obtained from LiLaTa2O6.15N0.57 precursor
摘要： Layered perovskite oxynitride LiLaTa2O6.15N0.57 with Dion-Jacobson phase was successfully exfoliated into colloidal suspension by using proton-exchange reaction and followed intercalation of ethylamine and tetrabutylammonium ion. According to the X-ray di?raction pattern, a basal spacing of the layered perovskite oxynitride concomitantly increased as the intercalation reaction with bulky cations proceeded. Transmission electron microscopy and atomic force microscopy analysis indicated that the exfoliated perovskite oxynitride was composed of single-layered and multi-stacked nanoplatelets. UV–vis di?use re?ectance showed that the self-reassembled perovskite oxynitride nanosheet also had characteristic absorption in a visible range, revealing that visible light harvesting property of the perovskite oxynitride maintained even after exfoliation and subsequent reassembling reaction. Extended X-ray absorption ?ne structure (EXAFS) analysis of samples clearly showed that structural disorder upon intercalation reaction resulted in damping of EXAFS oscillation, suggesting nanosized feature of the exfoliated nanosheet.
关键词： Exfoliation,XANES,Layered perovskite oxynitride,EXAFS,Intercalation
更新于2025-09-23 15:21:21
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Highly Enhanced Photocatalytic Water-splitting Activity of Gallium Zinc Oxynitride Derived from Flux-assisted Zn/Ga Layered Double Hydroxides
摘要： The Ga/Zn-oxynitride solid solution [(GaN)1-x(ZnO)x] is one of the promising visible-light harvesting photocatalysts for overall water-splitting. A series of (GaN)1-x(ZnO)x (0.11 ≤ x ≤ 0.33) are synthesized by calcining the carbonate-type Zn/Ga-LDH precursor with and without sodium carbonate flux at 850 oC for 8 - 14 h under a NH3 gas-flow. The solid solutions without flux are determined to be low in crystallinity but plate-like in morphology with preferred orientation could be observed. On the other hand, those with flux turn out to be better in crystallinity, and eventually exhibit significantly higher photocatalytic activity for overall water splitting under visible-light irradiation than those without flux. In addition, the bandgap energies can also be engineered from 2.57 eV to 2.72 eV by changing the synthetic parameter such as nitridation time. It is, therefore, suggested that the present new approach can offer new opportunities for designing the next generation photocatalytic systems.
关键词： Overall water splitting,Photocatalyst,Gallium Zinc Oxynitride,Layered double hydroxides,Flux
更新于2025-09-23 15:21:21
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TiOxNy Thin Film Sputtered on a Fiber Ball Lens as Saturable Absorber for Passive Q-Switched Generation of a Single-Tunable/Dual-Wavelength Er-Yb Double Clad Fiber Laser
摘要： The use of titanium oxynitride (TiOxNy) thin ?lms as a saturable absorber (SA) element for generation of passive Q-switched (PQS) laser pulses, from a linear cavity Er-Yb double-clad ?ber (EYDCF) laser, is demonstrated. Additionally, the deposition of the material as a thin ?lm covering a ?ber micro-ball lens (MBL) structure is reported for the ?rst time. The TiOxNy coating is deposited by a direct current (DC) magnetron-sputtering technique. The MBL is inserted within the laser cavity in a re?ection con?guration, alongside a re?ecting mirror. As a result, the coated ?ber MBL simultaneously acts as a SA element for PQS laser pulses generation and as an interference ?lter for wavelength selection and tuning of the generated laser line. Tunable single-laser emission in a wavelength range limited by dual-wavelength laser generation at 1541.96 and 1547.04 nm is obtained. PQS laser pulses with a repetition rate from 18.67 to 124.04 kHz, minimum pulse duration of 3.57 μs, maximum peak power of 0.359 W, and pulse energy of 1.28 μJ were obtained in a pump power range from 1 to 1.712 W.
关键词： Q-switched ?ber lasers,titanium oxynitride,DC magnetron sputtering,?ber micro-ball lens,saturable absorber materials
更新于2025-09-23 15:21:01
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Tungsten-Doped Zinc Oxide and Indiuma??Zinc Oxide Films as High-Performance Electron-Transport Layers in Na??Ia??P Perovskite Solar Cells
摘要： Perovskite solar cells (PSCs) have attracted tremendous research attention due to their potential as a next-generation photovoltaic cell. Transition metal oxides in N–I–P structures have been widely used as electron-transporting materials but the need for a high-temperature sintering step is incompatible with flexible substrate materials and perovskite materials which cannot withstand elevated temperatures. In this work, novel metal oxides prepared by sputtering deposition were investigated as electron-transport layers in planar PSCs with the N–I–P structure. The incorporation of tungsten in the oxide layer led to a power conversion efficiency (PCE) increase from 8.23% to 16.05% due to the enhanced electron transfer and reduced back-recombination. Scanning electron microscope (SEM) images reveal that relatively large grain sizes in the perovskite phase with small grain boundaries were formed when the perovskite was deposited on tungsten-doped films. This study demonstrates that novel metal oxides can be used as in perovskite devices as electron transfer layers to improve the efficiency.
关键词： transparent metal oxide,zinc–oxynitride,perovskite solar cell,tungsten-doped InZnO
更新于2025-09-23 15:19:57