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Simulation and Experimental Study on Properties of Ag/SnO <sub/>2</sub> Contact Materials Doped with Different Ratios of Ce
摘要： SnO2 in the Ag/SnO2 contact material is a kind of high hardness and almost insulated wide bandgap semiconductor material. In the process of use, the contact resistance is larger and the temperature rise is higher, which reduces the reliability of contacts and shortens the electrical life. In order to improve the properties of Ag/SnO2 contact materials, based on the first principle of density functional theory, this paper presents a method of doping SnO2 with the calculation of different proportions of rare earth Ce electrical and mechanical properties. The results of energy band, density of state, and elastic constant show that when the doping ratio of Ce is 0.125, the electron mobility is the highest, the conductivity is the best; the hardness decreases, and the universal elastic anisotropy index is the smallest. Finally, in the experiment, SnO2 powders with different doping ratios are prepared by the sol-gel method, and Ag/SnO2 contacts with different doping proportions are prepared by powder metallurgy. Arc energy, contact resistance, and hardness are measured; scanning electron microscopy was used to observe and analyze the surface morphology. The final simulation and experimental results are well matched.
关键词： doping,contact materials,rare earth Ce,conductivity,hardness,Ag/SnO2
更新于2025-09-10 09:29:36
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A green one-pot approach for mesoporous g-C3N4 nanosheets with in situ sodium doping for enhanced photocatalytic hydrogen evolution
摘要： Synchronous nano-structuring and element-doping of g-C3N4 were realized via a green one-pot approach to improve its photocatalytic activity. Na-doped mesoporous g-C3N4 nanosheets of ~5 nm in thickness were facilely synthesized by calcining a mixture of dicyandiamide and sodium chloride. NaCl not only serves as a con?ning-reactor to con?ne the growth of g-C3N4 into mesoporous nanosheets, but also acts as a sodium source for Na-doping. The nanosheets own greater speci?c surface area, stronger optical absorption and lower recombination of photo-induced electron-hole pairs than bulk g-C3N4, and exhibit an excellent visible-light photocatalytic hydrogen evolution ef?ciency which is about 13 times that of bulk g-C3N4. Moreover, the thermostable and hydrosoluble NaCl is simply removed and recycled by water and then directly reused in a new synthesis, making the process to be environmental-friendly and sustainable.
关键词： g-C3N4,Sodium chloride,Photocatalytic hydrogen evolution,Sodium doping,Mesoporous nanosheet
更新于2025-09-10 09:29:36
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Substrate Temperature Dependent Properties of Sputtered AlN:Er Thin Film for In-Situ Luminescence Sensing of Al/AlN Multilayer Coating Health
摘要： The integrity and reliability of surface protective coatings deposited on metal surface could be in-situ monitored via the attractive luminescence sensing technique. In this paper, we report the influence of substrate temperature on the properties of erbium (Er) doped aluminum nitride (AlN) film, which could be applied as a luminescent layer for monitoring the health of multilayered Al/AlN coating. The AlN:Er films were deposited via reactive radio-frequency magnetron sputtering, and the silicon substrate temperature was varied from non-intentional heating up to 400 ?C. The composition, morphology, crystalline structure, and dielectric function of the AlN:Er films deposited under these different substrate temperature conditions were studied. These properties of the AlN:Er films show strong correlation with the substrate temperature maintained during film fabrication. The obtained AlN:Er films, without further annealing, exhibited photoluminescence peaks of the Er3+ ions in the visible wavelength range and the strongest photoluminescence intensity was observed for the AlN:Er film deposited with the temperature of substrate kept at 300 ?C. The results demonstrated in this work offer guidance to optimize the substrate temperature for the deposition of AlN:Er film for future application of this sensing technique to thin metal components.
关键词： aluminum nitride,erbium doping,magnetron sputtering,luminescence sensing
更新于2025-09-10 09:29:36
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Impact of the anodization time on the photocatalytic activity of TiO <sub/>2</sub> nanotubes
摘要： Titanium oxide nanotubes (TNTs) were anodically grown in ethylene glycol electrolyte. The influence of the anodization time on their physicochemical and photoelectrochemical properties was evaluated. Concomitant with the anodization time, the NT length, fluorine content, and capacitance of the space charge region increased, affecting the opto-electronic properties (bandgap, bathochromic shift, band-edge position) and surface hydrophilicity of TiO2 NTs. These properties are at the origin of the photocatalytic activity (PCA), as proved with the photooxidation of methylene blue.
关键词： nanotubes,photocatalytic activity,photoelectrochemistry,titanium(IV) oxide (TiO2),fluorine doping
更新于2025-09-10 09:29:36
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Enhanced visible-light-driven photocatalytic activity of F doped reduced graphene oxide - Bi <sub/>2</sub> WO <sub/>6</sub> photocatalyst
摘要： The reduced graphene oxide‐Bi2WO6 (rGO‐BWO) photocatalysts with the different RF/O values (molar ratio of the F molar mass and the O's molar mass of Bi2WO6) had been successfully synthesized via one‐step hydrothermal method. The F‐doped rGO‐BWO samples were characterized by X‐ray diffraction patterns (XRD), field‐emission scanning electron microscopy (FE‐ESEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller surface area (BET), X‐ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra (DRS). The results indicate that F ions had been successfully doped into rGO‐BWO samples. With the increasing of the RF/O values from 0 to 2%, the evident change of the morphology and the absorption edges of F‐doped rGO‐BWO samples and the photocatalytic activities had been enhanced. Moreover, the photocatalytic activity of F‐doped rGO‐BWO with RF/O = 0.05 were better than rGO‐BWO and the other F‐doped rGO‐BWO under 500 W Xe lamp light irradiation. The enhanced photocatalytic activity can be attributed to the morphology of the intact microsphere that signify the bigger specific surface area for providing more possible reaction sites for the adsorption–desorption equilibrium of photocatalytic reaction, the introduction of F ions that may cause the enhancement of surface acidity and creation of oxygen vacancies under visible light irradiation, the narrower band gap which means needing less energy for the electron hole pair transition.
关键词： photocatalytic activity,rGO‐Bi2WO6,fluorine doping,hydrothermal method
更新于2025-09-10 09:29:36
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Tunable Schottky barrier width and enormously enhanced photoresponsivity in Sb doped SnS2 monolayer
摘要： Doping, which is the intentional introduction of impurities into a material, can improve the metal-semiconductor interface by reducing Schottky barrier width. Here, we present high-quality two-dimensional SnS2 nanosheets with well-controlled Sb doping concentration via direct vapor growth approach and following micromechanical cleavage process. X-ray photoelectron spectroscopy (XPS) measurement demonstrates that Sb contents of the doped samples are approximately 0.22%, 0.34% and 1.21%, respectively, and doping induces the upward shift of the Fermi level with respect to the pristine SnS2. Transmission electron microscopy (TEM) characterization exhibits that Sb-doped SnS2 nanosheets have a high-quality hexagonal symmetry structure and Sb element is uniformly distributed in the nanosheets. The phototransistors based on the Sb-doped SnS2 monolayers show n-type behavior with high mobility which is one order of magnitude higher than that of pristine SnS2 phototransistors. The photoresponsivity and external quantum efficiency (EQE) of Sb-SnS2 monolayers phototransistors are approximately three orders of magnitude higher than that of pristine SnS2 phototransistor. The results suggest that the method of reducing Shottky barrier width to achieve high mobility and photoresponsivity is effective, and Sb-doped SnS2 monolayer has significant potential in future nanoelectronic and optoelectronic applications.
关键词： doping,two-dimensional,SnS2,optoelectronics,Schottky barrier width
更新于2025-09-10 09:29:36
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Synthesis of All-Inorganic Cd-Doped CsPbCl <sub/>3</sub> Perovskite Nanocrystals with Dual-Wavelength Emission
摘要： Doped lead halide perovskite nanocrystals (NCs) have garnered significant attention due to their superior optoelectronic properties. Here, we report a synthesis of Cd-doped CsPbCl3 NCs by decoupling Pb- and Cl-precursors in a hot injection method. The resulting Cd-doped perovskite NCs manifest a dual-wavelength emission profile with the first reported example of Cd-dopant emission. By controlling Cd-dopant concentration, the emission profile can be tuned with a dopant emission quantum yield up to 8%. A new secondary emission (~610 nm) is induced by an energy transfer process from photo-excited hosts to Cd-dopants, and a subsequent electronic transition from excited state (3Eg) to ground state (1A1g) of [CdCl6]4- units. This electronic transition matches well with a first-principles density functional theory calculation. Further, the optical behavior of Cd-doped CsPbCl3 NCs can be altered through post-synthetic anion-exchange reactions. Our studies present a new model system for doping chemistry studies in semiconductors for various optoelectronic applications.
关键词： Energy transfer,Doping,Perovskite,Anion exchange,Nanocrystals
更新于2025-09-10 09:29:36
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Part I: Physical Insight Into Carbon-Doping-Induced Delayed Avalanche Action in GaN Buffer in AlGaN/GaN HEMTs
摘要： Physics behind the improvement in breakdown voltage of AlGaN/GaN HEMTs with carbon-doping of GaN buffer is discussed. Modeling of carbon as acceptor traps and self-compensating acceptor/donor traps is discussed with respect to their impact on avalanche breakdown. Impact of carbon behaving as a donor as well as acceptor traps on electric field relaxation and avalanche generation is discussed in detail to establish the true nature of carbon in GaN that delays the avalanche action. This understanding of the behavior of carbon-doping in GaN buffer is then utilized to discuss design parameters related to carbon doped buffer. Design parameters such as undoped channel thickness and relative trap concentration induced by carbon-doping are discussed with respect to the performance metrics of breakdown voltage, leakage current, sheet charge density, and dynamic ON-resistance.
关键词： AlGaN/GaN HEMTs,breakdown voltage,self-compensating traps,donor traps,Acceptor traps,buffer designing,carbon-doping
更新于2025-09-10 09:29:36
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Si doping superlattice structure on 6H-SiC(0001)
摘要： Si-DSL structures multilayers are prepared on 6H-SiC(0001) successfully. The energy offsets of the n-Si/n-6H-SiC heterojunction in the conduction band and valance band are 0.21eV and 1.65eV, respectively. TEM characterizations of the p/n-Si DSL confirms the epitaxial growth of the Si films with [1-11] preferred orientation and the misfit dislocations with a Burgers vector of 1/3 <21-1? at the p-Si/n-Si interface. J-V measurements indicate that the heterostructure has apparent rectifying behavior. Under visible illumination with light intensity of 0.6W/cm2, the heterostructure demonstrates significant photoelectric response, and the photocurrent density is 2.1mA/cm2. Non-UV operation of the SiC-based photoelectric device is realized.
关键词： non-UV operation,Si doping superlattice structure,photoelectric response,6H-SiC
更新于2025-09-10 09:29:36
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Identification of donor deactivation centers in heavily As-doped Si using time-of-flight medium-energy ion scattering spectroscopy
摘要： Electrically-inactive arsenic (As) complexes in silicon are investigated using time-of-flight medium-energy ion scattering spectroscopy. In heavily As-doped Si, the As atoms that are segregated in the Si interface region just below the SiO2 are found to be in interstitial forms (Asi), while the As atoms in the bulk Si region are found to be in the substitutional form (AsSi). Despite the substitutional form of As, most of the As are found to be electrically inactive in the bulk region, and we identify the As to be in the form of a h111i-oriented AsSi-Si-vacancy (AsSi-VSi) complex. The Asi atoms in the interface Si region are found to exist together with Si-interstitial atoms (Sii), suggesting that the Asi atoms in the interface Si region accompany the Sii atoms.
关键词： silicon,electrical deactivation,arsenic,doping,ion scattering spectroscopy
更新于2025-09-10 09:29:36