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Sulfur doping of M/In <sub/>2</sub> O <sub/>3</sub> (M=Al,W) nanowires with room temperature near infra red emission
摘要： We have investigated the growth of Al doped In2O3 nanowires via the vapor-liquid-solid mechanism at 800?C using Au as a catalyst. We find that the Al is not incorporated into the cubic bixbyite crystal structure of In2O3 but nevertheless was detected in the form of Al2O3. The nanowires had metallic like conductivities and exhibited photoluminescence at 2.3 eV which shifted to 1.5 eV after exposure to H2S above 500?C due to the formation of β-In2S3 and deep donor to acceptor transitions with a lifetime of ≈ 1 μs. The near infra red emission was also observed in W/In2O3 but not in W/SnO2 core-shell nanowires after processing under H2S at 600?C, confirming it is related to β-In2S3. The nanowires remain one dimensional up to 900?C due to the shell which is interesting for the fabrication of high temperature nanowire sensors.
关键词： β-In2S3,M/In2O3 nanowires,Al doped In2O3,room temperature near infra red emission,Sulfur doping
更新于2025-09-09 09:28:46
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Effect of indium and antimony doping on the transport properties of direct vapour transport (DVT) grown SnSe single crystals
摘要： Pure SnSe, 5% In, 10% In, 5% Sb, and 10% Sb doped SnSe single crystals were grown by the direct vapour transport technique. The energy dispersive X-ray analysis study of the samples showed them to be near stoichiometric but slightly Sn deficient. The X-ray diffraction study of all the as-grown single crystal samples showed that they possess an orthorhombic structure and the lattice parameters are in good agreement with the reported parameters. The thermoelectric power (S), dc electrical conductivity (σ), and thermal conductivity (κ) variation with temperature from ambient to 573 K substantiated the semiconducting nature of all the five samples. The sign of “S” was positive for all five samples for all the temperature range stating the sample to be a p-type semiconductor. The power factor (S2σ) and figure of merit (ZT) variation with temperature showed that pure SnSe possesses the highest value compared to doped samples. The obtained results are studied and discussed in detail.
关键词： direct vapour transport,thermoelectric,SnSe,doping,single crystals
更新于2025-09-09 09:28:46
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Electroluminescence of intrashell transitions in Eu doped single ZnO nanowires
摘要： Tunable nanoscale light emitters are essential to accomplish future multifunctional optoelectronic nano-devices. Here, we present an approach for achieving red electroluminescence from single ZnO nanowires implanted with Europium ions. The electroluminescence is emitted mainly from the end facets of ZnO nanowires at room temperature under the application of an AC voltage. The corresponding electroluminescence spectrum is attributed to the radiative intrashell transitions of the Eu ions, while contributions from near band edge or deep level emission of the ZnO remain absent. The total intensity of the electroluminescence is linearly proportional to the length of the nanowires, whereas there is no clear correlation with other morphology factors of the nanowire based device such as the diameter. Furthermore, the underlying excitation mechanism of the electroluminescence is proposed as direct-impact excitation of Eu ions by hot electrons in the ZnO nanowires.
关键词： electroluminescence,Zinc oxide (ZnO),Europium (Eu),nanowires,rare earth elements,ion beam doping
更新于2025-09-09 09:28:46
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Combined adsorption process and photocatalytic degradation of some commercial herbicides over N-doped TiO <sub/>2</sub> particles supported on recyclable magnetic hexagonal mesoporous silica
摘要： Magnetic hexagonal mesoporous silica (magnetic HMS) containing N-doped TiO2 was prepared by hydrothermal method and used for the removal of trifluralin, 2,4-dichlorophenoxyacetic acid, and glyphosate herbicides at the presence and absence of UV/visible lights. The prepared samples were found as efficient for the removal of the herbicides and easily recyclable after treatment by UV irradiation. A red shift effect by nitrogen doping was also observed in the prepared samples resulting photocatalytic activity at the presence of visible light. Kinetic studies indicated that the photodegradation followed as the first order and kUV ≈ 10kvis. The results also showed synergetic effects between the adsorption of herbicides on the surface of magnetic HMS and photoreactions over N-doped TiO2 species.
关键词： nitrogen doping,titanium oxide,herbicide,HMS,Photocatalyst
更新于2025-09-09 09:28:46
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Improved Negative Bias Stress Stability of Sol-Gel-Processed Mg-Doped In <sub/>2</sub> O <sub/>3</sub> Thin Film Transistors
摘要： We demonstrate sol–gel-processed Mg-doped In2O3 thin film transistors (TFTs) with high performance and improved stability. To improve the performance of indium oxide, which is unstable at a high negative threshold voltage, magnesium is used to suppress oxygen vacancy formation. As the Mg doping concentration increases, the oxygen deficiencies and OH impurities decrease, resulting in a positive shift in the threshold voltage and improved stability in negative bias stress environments. In this experiment, Mg-doped (0 to 2 wt%) indium oxide TFTs are fabricated. Indium oxide prepared from a synthesized solution of an indium nitrate hydrate precursor and 2-methoxyethanol has a mobility of 17.2 cm2/V s. In2O3 TFTs doped with 1 wt% Mg also show a high mobility of 11.02 cm2/V s and a noticeable ?1.5 V threshold voltage shift under negative bias stress. Our results suggest that the sol–gel-processed Mg-doped In2O3 TFTs are a promising candidate for use in high-stability and high-performance applications in transparent devices.
关键词： thin film transistors,negative bias stress,Mg doping,Sol-gel,In2O3
更新于2025-09-09 09:28:46
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The stability and electronic properties of Si-doped ZnO nanosheet: A DFT study
摘要： This work deals with stability, structural and electronic properties of perfect ZnO nanosheet and substiutionally doped ZnO nanosheet with Si are simulated and optimized successfully using density functional theory (DFT) with the help of SIESTA program in the generalized gradient approximation (GGA). The substitution atoms have been replaced on the oxygen site in line and zigzag doping. The stability of perfect ZnO nanosheet and ground state structures of Sin-ZnO (n=1-6) are studied in terms of binding energy, show that a maximum stabilized of one Si in line doping and two Si in zigzag doping due to the dopant located in the center of nanosheet is a more stable. The electronic properties of ZnO nanosheet and Si-doped are discussed using ionization potential, electron affinity, HOMO–LUMO gap, electronegativity, and hardness. The results showed the presence of silicon atoms substitution expands the bond length with respect to perfect ZnO nanosheets. The obtained values of HOMO and LUMO are slightly different and this suggests that different of position dopant play significant roles on electronic properties and large electron affinity at four silicon atoms doped ZnO nanosheet in two cases that it improved the electron more accepting ability. The study of HOMO-LUMO gap reveals that the gap decreases with the increase in number of Si dopant atoms in ZnO nanosheet. These results global gave molecular electronics important electronic applications and help us to replace some oxygen atoms instead of silicon atoms in ZnO nanosheet.
关键词： ZnO nanosheet,Silicon-doping,Electronic property.,Line & zigzag doping
更新于2025-09-04 15:30:14
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In <sub/>0.49</sub> Ga <sub/>0.51</sub> P/GaAs heterojunction bipolar transistors (HBTs) on 200 mm Si substrates: Effects of base thickness, base and sub-collector doping concentrations
摘要： We report performance of InGaP/GaAs heterojunction bipolar transistors (HBTs) fabricated on epitaxial films directly grown onto 200 mm silicon (Si) substrates using a thin 100% germanium (Ge) buffer layer. Both buffer layer and device layers were grown epitaxially using metalorganic chemical vapor deposition (MOCVD). With the assistance of numerical simulation, we were able to achieve high performance GaAs HBTs with DC current gain of ～100 through optimizing the base doping concentration (C-doped, ～ 1.9×1019/cm3), base layer thickness (～55 nm), and the sub-collector doping concentration (Te-doped, > 5×1018/cm3). The breakdown voltage at base (BV ceo) of higher than 9.43 V was realized with variation of < 3% across the 200 mm wafer. These results could enable applications such as power amplifiers for mobile phone handsets and monolithic integration of HBTs with standard Si-CMOS transistors on a common Si platform.
关键词： InGaP/GaAs heterojunction bipolar transistors,base doping concentrations,base thickness,Si substrates,HBTs,sub-collector doping concentrations
更新于2025-09-04 15:30:14
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Chemical Speciation and Mapping of the Si in Si Doped LFP Ingot with Synchrotron Radiation Technique
摘要： Development of LiFePO4 cathode material with high cycle life through Si doping (substituting Si at P sites of LiFePO4) has shown that small changes to the structure of LiFePO4 can significantly affect the performance of Li ion batteries. However, determining the nature of elemental doping and their effects on the electronic and atomic structure of LiFePO4 remains challenging. Here we present X-ray absorption spectroscopy and X-ray fluorescence mapping as ideal characterization methods for understanding the effect of Si doped LiFePO4 prepared using a melt-synthesis process. X-ray absorption spectra of silicon doped LiFePO4 indicate subtle changes in the local structure surrounding the dopants compared to SiO2 and amorphous glass phases formed as impurities in Si containing un-doped samples. The study of Fe and P K-edges X-ray absorption spectra illustrates the effect of Si in the LiFePO4 structure in doped and impurity containing samples. Utilizing X-ray absorption spectroscopy, in conjunction with X-ray fluorescence mapping, has enabled a better overview of the non-uniform nature of prepared ingot samples. These results highlight the power of X-ray absorption spectroscopy as a tool for better understanding the structure of modified LiFePO4 and subsequently designing materials for Li ion batteries. This article is protected by copyright. All rights reserved
关键词： Li ion battery,XRF mapping,XAS,silicon doping,LiFePO4
更新于2025-09-04 15:30:14
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Photodegradation of Methyl Orange Over CdS–TiO2/L-zeolite Composite Photocatalyst
摘要： A stable and active composite photocatalyst CdS–TiO2/L-zeolite has been synthesized through sol–gel method. The composite photocatalyst exhibits enhanced light harvesting in visible region indicating the improved photoresponsive ability because of CdS dopant. Photocatalytic conditions, such as the doping quantity of CdS, the concentration of photocatalyst, initial pH values and concentrations of methyl orange solutions have been systematically studied to obtain the highest photocatalytic efficiency. Photocatalytic kinetics of the composite photocatalyst is proved to conform to the first-order equation. The mechanism of the photocatalytic process is proposed in this work. L-zeolite support and CdS dopant could prevent the undesired electron/hole recombination and promote charge separation aiding for the continuous generation of active radicals. The novel composite photocatalyst shows good promise for applications in degrading environmental pollutants.
关键词： TiO2,Composite photocatalyst,Stability,CdS doping,L-zeolite
更新于2025-09-04 15:30:14
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Resistance-switching properties of Bi-doped $$\hbox {SrTiO}_{3}$$SrTiO3 films for non-volatile memory applications with different device structures
摘要： SrTiO3 and Bi-doped SrTiO3 ?lms were fabricated with different device structures using the sol–gel method for non-volatile memory applications, and their resistance-switching behaviour, endurance and retention characteristics were investigated. SrTiO3 and Sr0.92Bi0.08TiO3 ?lms grown on Si or Pt have the same phase structure, morphologies and grain size; however, the grain size of the Sr0.92Bi0.08TiO3 ?lms grown on Si is slightly larger than those of the SrTiO3 ?lms grown on Si and the Sr0.92Bi0.08TiO3 ?lms grown on Pt. The SrTiO3 or Sr0.92Bi0.08TiO3 ?lms grown on Si or Pt all exhibit bipolar resistive-switching behaviour and follow the same conductive mechanism; however, the Ag/Sr0.92Bi0.08TiO3/Si device possesses the highest RHRS/RLRS of 105 and the best endurance and retention characteristics. The doping of Bi is conducive to enhance the RHRS/RLRS of the SrTiO3 ?lms; meanwhile, the Si substrates help improve the endurance and retention characteristics of the Sr0.92Bi0.08TiO3 ?lms.
关键词： SrTiO3,resistance-switching properties,Bi doping,device structure,sol–gel
更新于2025-09-04 15:30:14