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Fabrication of large surface area nitrogen vacancy modified graphitic carbon nitride with improved visible-light photocatalytic performance
摘要： In this work, nitrogen vacancy modified graphitic carbon nitride (g-C3N4) with large surface area was synthesized and analyzed by a series of instruments, including XRD, FTIR, XPS, EPR SEM, TEM, DRS and PL, etc. and the photocatalytic H2-evolution activity was investigated. The results indicated that the as-synthesized g-C3N4 with nitrogen vacancy exhibited stronger visible light response capability, enlarged specific surface area and notably separated rate of photoinduced charge carriers, which caused the as-synthesized photocatalyst possessing the higher hydrogen evolution rate (5250 μmol h?1 g?1) and excellent recycle stability. Evidently, this work could provide a new insight for preparing highly efficient photocatalyst.
关键词： Large surface area,Nitrogen vacancy,Photocatalysis,g-C3N4,Photocatalytic performance
更新于2025-09-04 15:30:14
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Unraveling the oxygen effect on the property of sputtered BaSnO3 thin films
摘要： The perovskite oxide BaSnO3 is a highly topical material for next-generation transparent conducting semiconductors. The foreign chemical doping strategy is largely used to realize the high conductivity in BaSnO3. Removal of oxygen in BaSnO3 is another route to get high conductivity but the oxygen vacancy-property relationships have not been realized completely, which is of fundamental importance for the future optoelectronic applications. Here we report how the oxygen vacancies in sputtered BaSnO3 films can be accounted for the structural and chemical environment, the transport phenomena, and the optoelectronic properties. Oxygen vacancies in BaSnO3 films cause the expansion of the unit cell along the out-of-plane direction, enhance the conductivity, transform the electronic transport mechanism from the thermal activation model to the variable-range hopping (VRH) model, and spawn the sub-band level-assisted photoconduction. The present work further strengthens our understanding of the oxygen effect on the physical properties in BaSnO3-based systems.
关键词： oxygen vacancy,transport property,transparent conductive oxide,BaSnO3,photo response,thin film
更新于2025-09-04 15:30:14
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Correlation between Ni valence and resistance modulation on SmNiO <sub/>3</sub> chemical transistor
摘要： The resistance modulation under various gate voltage (Vg) application conditions was systematically studied for a chemical field effect transistor (FET) composed of a SmNiO3 (SNO) film channel and an ionic liquid gate insulator. The channel resistance of the SNO chemical FET changed nonlinearly over a wide range for different temperatures, Vg magnitudes, and Vg application durations. The correlation between the modulated resistance and the Ni valence state was quantitatively revealed using X-ray photoelectron spectroscopy. A model describing the resistance change with the Vg application conditions was proposed by considering the kinetics of the reduction reaction on the SNO channel. This model enables the resistance to be predicted for given Vg application conditions, and selective resistance modulation over a wide range of resistances has been demonstrated.
关键词： control resistance modulation,nonvolatile,redox reaction,oxygen vacancy,Nickelate thin film
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Determination of ratios of Auger electrons emission probabilities and K–L shell vacancy transfer probability for K and Ca compounds
摘要： Ratios of emission probabilities of Auger electrons (u = p(KLX)/p(KLL), ? = p(KXY)/p(KLL)) and the vacancy transfer probabilities from K to L shell, ηKL for K ve Ca compounds were studied using Ki (i = α, β) X-rays line intensities and WK the K shell fluorescence yields. We were used the experimental Kβ/Kα intensity ratios and K shell fluorescence yields WK . The obtained values were compared with the other theoretical values of K ve Ca elements.We could not make any comparison of the results of the K ve Ca compounds since there are no experimental and theoretical values for these compounds in the literature. The Ratios of emission probabilities of Auger electrons and the vacancy transfer probabilities for K ve Ca compounds are being reported here for the first time.
关键词： Fluorescent yield,Coster Kronig transition,Auger elektrons,Vacancy transfer
更新于2025-09-04 15:30:14
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Ferroelectric properties of Ag doped PbZr0.53Ti0.47O3 thin film deposited by sol–gel process
摘要： To suppress the generation of oxygen vacancy during the PbZr0.53Ti0.47O3 (PZT) film synthesis process, herein, the 0–3 type Ag/PZT film is chosen as a prototype to systematically investigate the mechanisms of oxygen vacancy decrease and the relationship of ferroelectric properties. The uniform and dense films were successfully fabricated on fluorine tin oxide glasses (FTO) by facile sol–gel processes. It is confirmed the existence of silver nanoparticles in the film, indicating the composite ferroelectric films are of 0–3 type. When Ag doping mole concentration is 0.010 in the sol, a large remnant polarization (Pr) of ~ 50.7 μΧ/cm2 is got, which is 37.9 μΧ/cm2 for pure PZT. UV–vis spectrum confirms the generation of Ag2O in the process of mixing the sol. Furthermore, the oxygen vacancies caused by natural evaporation of lead specie are effectively reduced because of the decomposition of Ag2O, confirmed by X-ray photoelectron spectroscopy. This work points out the generated Ag2O as the intermediate product is the key to achieve high remnant polarization in Ag/PZT based film and make it as a promising candidate for memory applications.
关键词： remnant polarization,oxygen vacancy,Ag doped PbZr0.53Ti0.47O3,sol–gel process,Ferroelectric properties
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Austin, TX, USA (2018.9.24-2018.9.26)] 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Carrier Transport in a Two-Dimensional Topological Insulator Nanoribbon in the Presence of Vacancy Defects.
摘要： We model transport through two-dimensional topological insulator (TI) nanoribbons. To model the quantum transport, we employ the non-equilibrium Green’s function approach. With the presented approach, we study the effect of lattice imperfections on the carrier transport. We observe that the topologically protected edge states of TIs are robust against a high percentage (2%) of vacancy defects. We also investigate tunneling of the edge states in two decoupled TI nanoribbons.
关键词： nanoribbon,vacancy defects,non-equilibrium Green’s function,carrier transport,two-dimensional topological insulator
更新于2025-09-04 15:30:14
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Imaging the Local Charge Environment of Nitrogen-Vacancy Centers in Diamond
摘要： Characterizing the local internal environment surrounding solid-state spin defects is crucial to harnessing them as nanoscale sensors of external fields. This is especially germane to the case of defect ensembles which can exhibit a complex interplay between interactions, internal fields, and lattice strain. Working with the nitrogen-vacancy (NV) center in diamond, we demonstrate that local electric fields dominate the magnetic resonance behavior of NV ensembles at a low magnetic field. We introduce a simple microscopic model that quantitatively captures the observed spectra for samples with NV concentrations spanning more than two orders of magnitude. Motivated by this understanding, we propose and implement a novel method for the nanoscale localization of individual charges within the diamond lattice; our approach relies upon the fact that the charge induces a NV dark state which depends on the electric field orientation.
关键词： diamond,local electric fields,nanoscale localization,nitrogen-vacancy center,magnetic resonance
更新于2025-09-04 15:30:14
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Reversible Control of Physical Properties via an Oxygen-Vacancy-Driven Topotactic Transition in Epitaxial La <sub/>0.7</sub> Sr <sub/>0.3</sub> MnO <sub/>3?</sub><i> <sub/>δ</sub></i> Thin Films
摘要： The vacancy distribution of oxygen and its dynamics directly affect the functional response of complex oxides and their potential applications. Dynamic control of the oxygen composition may provide the possibility to deterministically tune the physical properties and establish a comprehensive understanding of the structure–property relationship in such systems. Here, an oxygen-vacancy-induced topotactic transition from perovskite to brownmillerite and vice versa in epitaxial La0.7Sr0.3MnO3?δ thin films is identified by real-time X-ray diffraction. A novel intermediate phase with a noncentered crystal structure is observed for the first time during the topotactic phase conversion which indicates a distinctive transition route. Polarized neutron reflectometry confirms an oxygen-deficient interfacial layer with drastically reduced nuclear scattering length density, further enabling a quantitative determination of the oxygen stoichiometry (La0.7Sr0.3MnO2.65) for the intermediate state. Associated physical properties of distinct topotactic phases (i.e., ferromagnetic metal and antiferromagnetic insulator) can be reversibly switched by an oxygen desorption/absorption cycling process. Importantly, a significant lowering of necessary conditions (temperatures below 100 °C and conversion time less than 30 min) for the oxygen reloading process is found. These results demonstrate the potential applications of defect engineering in the design of perovskite-based functional materials.
关键词： La0.7Sr0.3MnO3 films,polarized neutron reflectometry,brownmillerite,oxygen vacancy ordering,magnetism
更新于2025-09-04 15:30:14
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Monoisotopic Ensembles of Silicon-Vacancy Color Centers with Narrow-Line Luminescence in Homoepitaxial Diamond Layers Grown in H <sub/>2</sub> –CH <sub/>4</sub> – <sup> [ <i>x</i> ] </sup> SiH <sub/>4</sub> Gas Mixtures ( <i>x</i> = 28, 29, 30)
摘要： Silicon-vacancy (SiV?) color center in diamond is of high interest for applications in nanophotonics and quantum information technologies, as a single photon emitter with excellent spectral properties. To obtain spectrally identical SiV? emitters, we doped homoepitaxial diamond ?lms in situ with 28Si, 29Si, and 30Si isotopes using isotopically enriched (>99.9%) silane SiH4 gas added in H2?CH4 mixtures in the course of the microwave plasma-assisted chemical vapor deposition process. Zero-phonon line components as narrow as ～4.8 GHz were measured in both absorption and luminescence spectra for the monoisotopic SiV? ensembles with a concentration of a few parts per billion. We determined with high accuracy the Si isotopic energy shift of SiV? zero-phonon line. The SiV? emission intensity is shown to be easily controlled by the doped epi?lm thickness. Also, we identi?ed and characterized the localized single photon SiV? sources. The developed doping process opens a way to produce the SiV? emitter ensembles with energy con?ned in an extremely narrow range.
关键词： diamond,silicon-vacancy center,CVD synthesis,optical absorption,photoluminescence,doping,silicon isotope
更新于2025-09-04 15:30:14