Articles de revues : « Oxide doping »

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Rodwihok, Chatchai, Duangmanee Wongratanaphisan, Tran Van Tam, Won Mook Choi, Seung Hyun Hur et Jin Suk Chung. « Cerium-Oxide-Nanoparticle-Decorated Zinc Oxide with Enhanced Photocatalytic Degradation of Methyl Orange ». Applied Sciences 10, n^o 5 (2 mars 2020) : 1697. http://dx.doi.org/10.3390/app10051697.

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Cerium-oxide-nanoparticle-decorated zinc oxide was successfully prepared using a simple one-pot hydrothermal technique with different weight% Ce doping. It was found that an increase in Ce doping has an effect on the optical energy band-gap tunability. Ce dopant provides electron trapping on Ce/ZnO nanocomposites and also acts as a surface defect generator during hydrothermal processing. Additionally, a bi-metal oxide heterojunction forms, which acts as a charge separator to obstruct charge recombination and to increase the photodegradation performance. It was found that the methyl orange (MO) degradation performance improved with an increase in Ce doping. The decomposition of MO went from 69.42% (pristine ZnO) to 94.06% (7% Ce/ZnO) after 60 min under fluorescent lamp illumination.

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Marincaş, Alexandru-Horaţiu, et Petru Ilea. « Enhancing Lithium Manganese Oxide Electrochemical Behavior by Doping and Surface Modifications ». Coatings 11, n^o 4 (15 avril 2021) : 456. http://dx.doi.org/10.3390/coatings11040456.

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Lithium manganese oxide is regarded as a capable cathode material for lithium-ion batteries, but it suffers from relative low conductivity, manganese dissolution in electrolyte and structural distortion from cubic to tetragonal during elevated temperature tests. This review covers a comprehensive study about the main directions taken into consideration to supress the drawbacks of lithium manganese oxide: structure doping and surface modification by coating. Regarding the doping of LiMn2O4, several perspectives are studied, which include doping with single or multiple cations, only anions and combined doping with cations and anions. Surface modification approach consists in coating with different materials like carbonaceous compounds, oxides, phosphates and solid electrolyte solutions. The modified lithium manganese oxide performs better than pristine samples, showing improved cyclability, better behaviour at high discharge c-rates and elevated temperate and improves lithium ions diffusion coefficient.

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Robertson, John, et Zhaofu Zhang. « Doping limits in p-type oxide semiconductors ». MRS Bulletin 46, n^o 11 (novembre 2021) : 1037–43. http://dx.doi.org/10.1557/s43577-021-00211-3.

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AbstractThe ability to dope a semiconductor depends on whether the Fermi level can be moved into its valence or conduction bands, on an energy scale referred to the vacuum level. For oxides, there are various suitable n-type oxide semiconductors, but there is a marked absence of similarly suitable p-type oxides. This problem is of interest not only for thin-film transistors for displays, or solar cell electrodes, but also for back-end-of-line devices for the semiconductor industry. This has led to a wide-ranging search for p-type oxides using high-throughput calculations. We note that some proposed p-type metal oxides have cation s-like lone pair states. The defect energies of some of these oxides were calculated in detail. The example SnTa2O6 is of interest, but others have structures more closely based on perovskite structure and are found to have more n-type than p-type character. Graphic abstract

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Lu, Pei Hsuan Doris, Alison Lennon et Stuart Wenham. « Laser-Doping through Anodic Aluminium Oxide Layers for Silicon Solar Cells ». Journal of Nanomaterials 2015 (2015) : 1–8. http://dx.doi.org/10.1155/2015/870839.

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This paper demonstrates that silicon can be locally doped with aluminium to form localised p+surface regions by laser-doping through anodic aluminium oxide (AAO) layers formed on the silicon surface. The resulting p+regions can extend more than 10 μm into the silicon and the electrically active p-type dopant concentration exceeds 1020 cm−3for the first 6-7 μm of the formed p+region. Anodic aluminium oxide layers can be doped with other impurities, such as boron and phosphorus, by anodising in electrolytes containing the extrinsic impurities in ionic form. The ions become trapped in the formed anodic oxide during anodisation, therefore enabling the impurity to be introduced into the silicon, with aluminium, during laser-doping. This codoping process can be used to create very heavily doped surface layers which can reduce contact resistance on metallisation, whilst the deeper doping achieved by the intrinsic aluminium may act to shield the surface from minority carriers. laser-doping through AAO layers can be performed without introducing any voids in the silicon or fumes which may be harmful to human health.

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Yoshida, Hidehiro, Koji Morita, Byung Nam Kim et Keijiro Hiraga. « Grain Boundary Nanostructure and High Temperature Plastic Flow in Polycrystalline Oxide Ceramics ». Materials Science Forum 638-642 (janvier 2010) : 1731–36. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.1731.

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High temperature creep and superplastic flow in high-purity, polycrystalline oxide ceramics is very sensitive to a small amount of doping by various oxides. The doping effect is attributed to change in grain boundary diffusivity owing to grain boundary segregation of the doped cations. The doping effect on the grain boundary diffusivity is caused mainly by change of chemical bonding state in the vicinity of the grain boundary segregated with the doped cations. In other words, controlling of grain boundary nanostructure based on the doping process will be a useful way to develop new high-performance functional ceramics in the near future.

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den Engelsen, Daniel, et Georg Gaertner. « Rare earth oxide doping in oxide cathodes ». Applied Surface Science 253, n^o 2 (novembre 2006) : 1023–28. http://dx.doi.org/10.1016/j.apsusc.2006.04.046.

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Meffert, Matthias, Heike Störmer et Dagmar Gerthsen. « Dopant-Site Determination in Y- and Sc-Doped (Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δby Atom Location by Channeling Enhanced Microanalysis and the Role of Dopant Site on Secondary Phase Formation ». Microscopy and Microanalysis 22, n^o 1 (22 décembre 2015) : 113–21. http://dx.doi.org/10.1017/s1431927615015536.

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Abstract(Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ(BSCF) is a promising material with mixed ionic and electronic conductivity which is considered for oxygen separation membranes. Selective improvement of material properties, e.g. oxygen diffusivity or suppression of secondary phase formation, can be achieved by B-site doping. This study is concerned with the formation of Co-oxide precipitates in undoped BSCF at typical homogenization temperatures of 1,000°C, which act as undesirable nucleation sites for other secondary phases in the application-relevant temperature range. Y-doping successfully suppresses Co-oxide formation, whereas only minor improvements are achieved by Sc-doping. To understand the reason for the different behavior of Y and Sc, the lattice sites of dopant cations in BSCF were experimentally determined in this work. Energy-dispersive X-ray spectroscopy in a transmission electron microscope was applied to locate dopant sites exploiting the atom location by channeling enhanced microanalysis technique. It is shown that Sc exclusively occupies B-cation sites, whereas Y is detected on A- and B-cation sites in Y-doped BSCF, although solely B-site doping was intended. A model is presented for the suppression of Co-oxide formation in Y-doped BSCF based on Y double-site occupancy.

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McGhee, Joseph, et Vihar P. Georgiev. « Simulation Study of Surface Transfer Doping of Hydrogenated Diamond by MoO3 and V2O5 Metal Oxides ». Micromachines 11, n^o 4 (20 avril 2020) : 433. http://dx.doi.org/10.3390/mi11040433.

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In this work, we investigate the surface transfer doping process that is induced between hydrogen-terminated (100) diamond and the metal oxides, MoO3 and V2O5, through simulation using a semi-empirical Density Functional Theory (DFT) method. DFT was used to calculate the band structure and charge transfer process between these oxide materials and hydrogen terminated diamond. Analysis of the band structures, density of states, Mulliken charges, adsorption energies and position of the Valence Band Minima (VBM) and Conduction Band Minima (CBM) energy levels shows that both oxides act as electron acceptors and inject holes into the diamond structure. Hence, those metal oxides can be described as p-type doping materials for the diamond. Additionally, our work suggests that by depositing appropriate metal oxides in an oxygen rich atmosphere or using metal oxides with high stochiometric ration between oxygen and metal atoms could lead to an increase of the charge transfer between the diamond and oxide, leading to enhanced surface transfer doping.

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El-Shobaky, Gamil A., Nagi R. E. Radwan et Farouk M. Radwan. « Catalytic Decomposition of H2O2 over Pure and Li2O-Doped Co3O4 Solids ». Adsorption Science & ; Technology 16, n^o 9 (octobre 1998) : 733–46. http://dx.doi.org/10.1177/026361749801600906.

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Pure and doped Co3O4 samples were prepared by the thermal decomposition at 500–900°C of pure and lithium nitrate-treated basic cobalt carbonate. The amounts of dopant added were varied in the range 0.75–6 mol% Li2O. The effects of this treatment on the surface and catalytic properties of cobaltic oxide solid were investigated using nitrogen adsorption at −196°C and studies of the decomposition of H2O2 at 30–50°C. The results obtained revealed that Li2O doping of Co3O4 followed by heat treatment at 500°C and 600°C resulted in a progressive increase in the value of the specific surface area, SBET, to an extent proportional to the amount of dopant present. However, the increase was more pronounced in the case of solid samples calcined at 500°C. This increase in the specific surface areas has been attributed to the fixation of a portion of the dopant ions on the uppermost surface layers of the solid leading to outward growth of the surface lattice. The observed increase in SBET due to Li2O doping at 500°C might also result from a narrowing of the pores in the treated solid as a result of the doping process. Lithium oxide doping of cobaltic oxide followed by heat treatment at 700–900°C resulted in a significant decrease in the SBET, Vp and r̄ values. Pure and doped solids precalcined at 500°C and 600°C exhibited extremely high catalytic activities which were not much affected by doping with Li2O. On the other hand, doping followed by calcination at 700–900°C brought about a considerable and progressive increase in the catalytic activity of the treated solids. This treatment did not modify the activation energy of the catalysed reaction, i.e. doping of Co3O4 solid followed by heating at 700°C and 900°C did not alter the mechanism of the catalytic reaction but increased the concentration of catalytically active constituents taking part in the catalytic process without altering their energetic nature.

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Lehr, Daniela, Markus R. Wagner, Johanna Flock, Julian S. Reparaz, Clivia M. Sotomayor Torres, Alexander Klaiber, Thomas Dekorsy et Sebastian Polarz. « A single-source precursor route to anisotropic halogen-doped zinc oxide particles as a promising candidate for new transparent conducting oxide materials ». Beilstein Journal of Nanotechnology 6 (18 novembre 2015) : 2161–72. http://dx.doi.org/10.3762/bjnano.6.222.

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Numerous applications in optoelectronics require electrically conducting materials with high optical transparency over the entire visible light range. A solid solution of indium oxide and substantial amounts of tin oxide for electronic doping (ITO) is currently the most prominent example for the class of so-called TCOs (transparent conducting oxides). Due to the limited, natural occurrence of indium and its steadily increasing price, it is highly desired to identify materials alternatives containing highly abundant chemical elements. The doping of other metal oxides (e.g., zinc oxide, ZnO) is a promising approach, but two problems can be identified. Phase separation might occur at the required high concentration of the doping element, and for successful electronic modification it is mandatory that the introduced heteroelement occupies a defined position in the lattice of the host material. In the case of ZnO, most attention has been attributed so far to n-doping via substitution of Zn2+ by other metals (e.g., Al3+). Here, we present first steps towards n-doped ZnO-based TCO materials via substitution in the anion lattice (O2− versus halogenides). A special approach is presented, using novel single-source precursors containing a potential excerpt of the target lattice 'HalZn·Zn3O3' preorganized on the molecular scale (Hal = I, Br, Cl). We report about the synthesis of the precursors, their transformation into halogene-containing ZnO materials, and finally structural, optical and electronic properties are investigated using a combination of techniques including FT-Raman, low-T photoluminescence, impedance and THz spectroscopies.

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Khlayboonme, S. Tipawan, et Warawoot Thowladda. « Synthesis and Characterization of Cu-Doped SnO₂ Thin Films by Aerosol Pyrolysis Technique for Gas Sensor Application ». Key Engineering Materials 766 (avril 2018) : 205–10. http://dx.doi.org/10.4028/www.scientific.net/kem.766.205.

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Thin films of un-doped and Cu-doped tin oxide were synthesized on quartz substrates by the purpose-built aerosol pyrolysis apparatus from 0.2 M SnCl4.5H2O – ethanol solution. CuCl2.2H2O was used as a source of Cu dopant. The Cu dopant of 1, 3 and 5 wt.% were used for doping SnO2 film. The morphological, structural, optical and electrical properties under the influence of the Cu-doping was examined by FE-SEM, XRD, UV-Vis transmission spectroscopy and Hall effect measurement technique. XRD patterns of all films exhibited rutile-phase SnO2. The doping content of 1%Cu improved the film crystallinity. The Cu doping content decreased optical bandgap from 4.36 eV for undoped SnO2 to 4.28 eV for 3%Cu-doped SnO2. The further Cu doping content increased the bandgap energy to 4.32 eV. The resistivity was increased for doping of Cu 1% but it was decreased with further increasing in Cu-doping contents

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Wang, Lin, Yuan Jun Sun, Jian Hai Luo, Yon Gan Zhu et Ping Wen Niu. « Influences of Doping Methods on Microstructure and Fracture Toughness of Mo-La Alloys ». Materials Science Forum 534-536 (janvier 2007) : 1265–68. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.1265.

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Lanthanum oxide was introduced to molybdenum powder by liquid-liquid doping and liquid-solid doping respectively. Mo alloys were prepared by powder metallurgy technology. The size distribution and feature of dopant particles and the fractographs of Mo alloys were investigated by TEM and SEM respectively. The results indicated that liquid-liquid doping method is favorable for refining and dispersing La2O3 particles uniformly in matrix. Fracture toughness of Mo alloys prepared by liquid-liquid doping showed better results than that of liquid-solid doping. Furthermore, the influences of the size distribution of La2O3 on properties of Mo alloys was discussed by dislocation pile-up theory.

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Zhao, Hai, et Jun Qing Liu. « Effect of Rare Earth for Removal of Carbonyl Sulfide from Synthesis Gas ». Advanced Materials Research 860-863 (décembre 2013) : 1017–20. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.1017.

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Fe-Mn metal oxides nanosized particles have been prepared by doping with La. The effects of promoters on the oxides were investigated by XRD, BET and other methods. XRD results revealed that the degree of crystallinity and particle size of mixed oxide phase decreased due to doping with La2O3. Addition of La led to a progressive increase in the surface area of the sample. Tests showed that the addition of 3 wt % La2O3 greatly improved the absorption sulfur capacity of the sorbent for COS removal. Keywords: Hydrogen utilized; Carbonyl Sulfide; Doping; La2O3

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Licurgo, J. S. C., G. R. de Almeida Neto et H. R. Paes Junior. « Structural, electrical and optical properties of copper-doped zinc oxide films deposited by spray pyrolysis ». Cerâmica 66, n^o 379 (septembre 2020) : 284–90. http://dx.doi.org/10.1590/0366-69132020663792877.

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Abstract The effect of copper doping on structural, electrical, and optical properties of zinc oxide films was evaluated. Copper-doped films (ZnO:Cu) were successfully deposited on a glass substrate by spray pyrolysis at doping levels of 0, 2.5, and 7.5 at% (ZnO, ZC2.5, ZC7.5). All films were polycrystalline, single-phase with ZnO hexagonal wurtzite structure. The films presented nanostructured crystallites, from 36.7 to 38.2 nm. Cu doping increased the electrical conductivity of the ZnO films; this change was proportional to the Cu concentration. The films presented high optical transmittance of 70-80% in the visible wavelength. The energy gap decreased upon Cu doping. The photoluminescence spectrum of all films displayed an intense ultraviolet emission and a weaker blue emission. The emissions shifted to lower wavelengths with increasing dopant concentrations. ZC7.5 presented the most promising properties for an application as transparent conducting oxide: intense optical transmittance and UV photoluminescence, also the lowest electrical resistivity.

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Hu, Bo, Shuofeng Jian, Ge Yin, Wenhao Feng, Yaowen Cao, Jiaxuan Bai, Yanan Lai, Huiyun Tan et Yifan Dong. « Hetero-Element-Doped Molybdenum Oxide Materials for Energy Storage Systems ». Nanomaterials 11, n^o 12 (6 décembre 2021) : 3302. http://dx.doi.org/10.3390/nano11123302.

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In order to meet the growing demand for the electronics market, many new materials have been studied to replace traditional electrode materials for energy storage systems. Molybdenum oxide materials are electrode materials with higher theoretical capacity than graphene, which was originally used as anode electrodes for lithium-ion batteries. In subsequent studies, they have a wider application in the field of energy storage, such as being used as cathodes or anodes for other ion batteries (sodium-ion batteries, potassium-ion batteries, etc.), and electrode materials for supercapacitors. However, molybdenum oxide materials have serious volume expansion concerns and irreversible capacity dropping during the cycles. To solve these problems, doping with different elements has become a suitable option, being an effective method that can change the crystal structure of the materials and improve the performances. Therefore, there are many research studies on metal element doping or non-metal doping molybdenum oxides. This paper summarizes the recent research on the application of hetero-element-doped molybdenum oxides in the field of energy storage, and it also provides some brief analysis and insights.

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Ryabko A. A., Mazing D.S., Bobkov A. A., Maximov A. I., Levitskii V. S., Lazneva E. F., Komolov A. S., Moshnikov V. A. et Terukov E. I. « Interface doping of zinc oxide nanorods ». Physics of the Solid State 64, n^o 11 (2022) : 1657. http://dx.doi.org/10.21883/pss.2022.11.54187.408.

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The effect of an increase in the electrical conductivity of a system of zinc oxide nanorods by a factor of 105 during atomic layer deposition of a thin dielectric layer of aluminum oxide was found. It is shown that a change in the electrical conductivity of zinc oxide during atomic layer deposition of aluminum oxide on the surface is also observed for thin polycrystalline layers of zinc oxide. A study of polycrystalline layers of zinc oxide coated with aluminum oxide using ultraviolet and X-ray photoelectron spectroscopy is presented. Based on the results of photoelectron spectroscopy, two main factors for changing the electrical conductivity are proposed, which consist in the formation of a two-dimensional electron gas at the ZnO|Al2O3 interface and doping of the near-surface region of zinc oxide with aluminum atoms. Keywords: nanorods, zinc oxide, aluminum oxide, atomic layer deposition, transparent electrodes, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy.

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Abass, Hawraa Hadi, et Bushra A. Hasan. « Impact of Aluminum Oxide Content on the Structural and Optical Properties of ZnO : AlO Thin Films ». Iraqi Journal of Physics (IJP) 19, n^o 51 (1 décembre 2021) : 41–53. http://dx.doi.org/10.30723/ijp.v19i51.685.

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AlO-doped ZnO nanocrystalline thin films from with nano crystallite size in the range (19-15 nm) were fabricated by pulsed laser deposition technique. The reduction of crystallite size by increasing of doping ratio shift the bandgap to IR region the optical band gap decreases in a consistent manner, from 3.21to 2.1 eV by increasing AlO doping ratio from 0 to 7wt% but then returns to grow up to 3.21 eV by a further increase the doping ratio. The bandgap increment obtained for 9% AlO dopant concentration can be clarified in terms of the Burstein–Moss effect whereas the aluminum donor atom increased the carrier's concentration which in turn shifts the Fermi level and widened the bandgap (blue-shift). The engineering of the bandgap by low concentration of AlO dopant makes ZnO: AlO thin films favorable for the fabrication of optoelectronic devices. The optical constants were calculated and was found to be greatly affected by the increasing the doping ratio.

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Ye, Zhi Guo, Xian Liang Zhou, Hui Min Meng, Xiao Zhen Hua, Ying Hu Dong et Ai Hua Zou. « The Electrochemical Characterization of Electrochemically Synthesized MnO₂-Based Mixed Oxides for Supercapacitor Applications ». Advanced Materials Research 287-290 (juillet 2011) : 1290–98. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1290.

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Nanostructured elements, including: manganese-molybdenum (Mn-Mo) oxide, manganese-molybdenum-tungsten (Mn-Mo-W) oxide, manganese-molybdenum-iron (Mn-Mo-Fe) oxide, manganese-molybdenum-cobalt (Mn-Mo-Co) oxide, manganese-vanadium-tungsten (Mn-V-W) oxide, manganese-vanadium-iron (Mn-V-Fe) oxide and manganese-iron (Mn-Fe) oxide, have been anodically deposited onto titanium substrates by employing an iridium dioxide interlayer (Ti/IrO2anode). The electrochemical characteristics of the resultant oxide deposits have been investigated by cyclic voltammetry (CV) in an aqueous 0.1 M Na2SO4solution. The voltammetric behaviors of the oxide deposits observed are significantly influenced by the doped elements. Molybdenum doping is found to be advantageous at improving the capacitance characteristics of anodically deposited manganese oxide. Comparatively, iron and vanadium doping are found to be unfavorable. The structure and crystallinity of these deposits have been identified by X-ray diffraction (XRD). The surface morphologies of these oxides were acquired from field emission scanning electron microscopes (FESEM). The high values of electrical parameters for the doped deposits are attributed to the net-like and sponge-like nanostructure, and low crystallinity of the doped manganese oxides. The deposit of Mn-Mo oxides exhibits an excellent capacitive-like behavior, possessing the maximum specific capacitance of 810 F g-1at a CV scan rate of 5 mV s-1in aqueous 0.1 M Na2SO4solution.

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Jurasz, Zbigniew, Krzysztof Adamaszek, Romuald Janik, Zbigniew Grzesik et Stanisław Mrowec. « Doping Effect in Nickel Oxide ». Defect and Diffusion Forum 289-292 (avril 2009) : 775–82. http://dx.doi.org/10.4028/www.scientific.net/ddf.289-292.775.

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Detailed investigations of nonstoichiometry as well as chemical and self-diffusion in nickel oxide have shown that doubly ionised cation vacancies and electron holes are the predominant defects in this material. The present work is an attempt to demonstrate that aliovalent impurities (Cr, Al, Na and Li) may considerably influence the concentration of these defects and, consequently, the oxidation rate of nickel at high temperatures. It has been shown that small amounts of tri-valent impurities (Cr, Al) bring about an increase of the oxidation rate, while mono-valent ones (Li, Na) decrease the rate of oxidation. These phenomena may satisfactorily be explained in terms of a doping effect. All experiments have been carried out as a function of temperature (1373-1673 K) and oxygen pressure (1-105 Pa) and consequently, it was possible to determine the influence of impurities not only on the oxidation rate but also on the activation energy of reaction and its pressure dependence. The results of these investigations could again be elucidated in terms of doping effect.

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Matsumoto, Yasumichi, Michio Koinuma, Yoshifumi Iwanaga, Tetsuya Sato et Shintaro Ida. « N Doping of Oxide Nanosheets ». Journal of the American Chemical Society 131, n^o 19 (20 mai 2009) : 6644–45. http://dx.doi.org/10.1021/ja807388t.

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Chung, Chih-Hung, Chiung-Yuan Lin, Tsung-Fu Yang, Hsin-Hui Huang, Tuo-Hung Hou et Blanka Magyari-Köpe. « Suppressing the filament formation by aluminum doping in anatase titanium oxide ». AIP Advances 12, n^o 12 (1 décembre 2022) : 125212. http://dx.doi.org/10.1063/5.0127412.

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For a resistance random access memory whose insulating matrix is based on transition metal oxides, the underlying microscopic mechanism of its conductive filaments is crucial yet challenging to understand. In this paper, our first-principles calculations predict that titanium oxide prefers its anatase phase over rutile either with or without aluminum doping. We report that an oxygen vacancy in the anatase titanium oxide is stable in its neutral charge state when free of an external field, while it is unstable in the singly and doubly charged states. By calculating the dissociation energy of a single vacancy from a conductive filament, we also study the filament rupture that is modeled by an array of oxygen vacancies, with or without a nearby aluminum dopant. We find that for the dopants at a specific site, the conductive filaments tend to disconnect, which, in turn, enhances the endurance of a non-filamentary resistance random access memory.

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Zhang, Xian Long, Lian Feng Zhang, Heng Jian Zhang, Xue Ping Wu, Jun Nan Cheng, Cheng Hua Xie et Cai Xia Yin. « Promotion of Cerium Oxide as Additive over MnOx/PG SCR Catalysts for Low Temperature Flue Gas NO Removal ». Advanced Materials Research 726-731 (août 2013) : 2264–69. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.2264.

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Manganese oxides supported palygorskite (MnOx/PG) catalysts used for low-temperature selective catalytic reduction of NO with NH3was modified by doping cerium oxide as additive for enhancement of its performance. The effects of doped cerium content on catalysts' activity were investigated. It was found that the NO removal efficiency of Mn8Ce5/PG catalyst was remarkably higher than Mn8/PG catalyst especially at low temperatures, revealing that the addition of cerium oxide effectively enhanced the catalysts' SCR activity. Catalysts were characterized by BET, XRD, XPS to explore the relation between structural properties and increasing in SCR activity via modification. Results showed that the doping of cerium oxide has improved the dispersion of manganese oxides as active species. And furthermore, the stability of surface MnO2was also improved which was suggested to be the main reason for the enhancement of catalysts' activity.

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Toh, W. S., Z. H. Zhou, J. M. Xue, J. Wang, Zoe H. Barber et J. E. Evetts. « Nanocrystalline W-Doped SrBi₂Ta₂O₉ of Layered Perovskite Structure Derived from Mechanical Activation ». Journal of Metastable and Nanocrystalline Materials 23 (janvier 2005) : 59–62. http://dx.doi.org/10.4028/www.scientific.net/jmnm.23.59.

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To study the effects of doping the layered perovskite SrBi2Ta2O9 with an appropriate amount of tungsten, both undoped and W-doped SrBi2Ta2O9 (SBT) of nanocrystallinity were synthesized by mechanical activation of constituent oxides of strontium oxide, bismuth oxide, tantalum oxide and tungsten oxide at room temperature. A nanocrystalline single perovskite phase was observed in SrBi2(Ta1-xWx)2O9 with up to x=0.1. SrBi2(Ta0.9W0.1)2O9 shows a higher Curie temperature than that of undoped SBT, although it exhibits a very similar layered perovskite structure. The ferroelectric and impedance behaviors of SrBi2 (Ta0.9W0.1)2O9 were studied over a range of test temperatures and frequencies, in order to understand the effects of W-doping in SBT, given that W exhibits a similar ionic size to Ta but with a variable valence.

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Sun, Yuan Jun, Guo Jun Zhang, Chao Zuo, Jian Feng Wei et Jun Sun. « Microstructure and Tensile Properties of Oxide Dispersion Strengthened Molybdenum Alloys Prepared by Different Doping Process ». Key Engineering Materials 353-358 (septembre 2007) : 481–84. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.481.

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The oxide lanthanum dispersion strengthened molybdenum alloys were prepared by proprietary powder metallurgy technology, in which the Mo-La2O3 powders were prepared by liquid-liquid doping process which the oxide lanthanum was added to ammonium bi-molybdate solutions as aqueous solutions of La(NO3)3 and liquid-solid doping process which the oxide lanthanum was added to molybdenum oxide solid particles as aqueous solutions of La(NO3)3, respectively. The microstructure and tensile properties of the molybdenum alloys were investigated at room temperature. The results show that the molybdenum alloys all have fine molybdenum grains, and the molybdenum alloy prepared by liquid-solid doping process mainly contain fine oxide lanthanum particles of submicron and nano-sized while the alloy prepared by liquid-liquid doping process mainly contain nano-sized fine oxide lanthanum particles. The molybdenum alloys prepared by liquid-liquid doping process have higher yield strength and ductility than yield-solid doping process. The results of strengthen mechanism analysis show that the high strength of the molybdenum alloys can be advisablely explained by the fine grain strengthening and particles dispersion strengthening mechanism through the Hall–Petch relationship and Orowan model.

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Modafferi, Vincenza, Claudia Triolo, Michele Fiore, Alessandra Palella, Lorenzo Spadaro, Nicolò Pianta, Riccardo Ruffo, Salvatore Patanè, Saveria Santangelo et Maria Grazia Musolino. « Effect of Hematite Doping with Aliovalent Impurities on the Electrochemical Performance of α-Fe2O3@rGO-Based Anodes in Sodium-Ion Batteries ». Nanomaterials 10, n^o 8 (12 août 2020) : 1588. http://dx.doi.org/10.3390/nano10081588.

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The effect of the type of dopant (titanium and manganese) and of the reduced graphene oxide content (rGO, 30 or 50 wt %) of the α-Fe2O3@rGO nanocomposites on their microstructural properties and electrochemical performance was investigated. Nanostructured composites were synthesized by a simple one-step solvothermal method and evaluated as anode materials for sodium ion batteries. The doping does not influence the crystalline phase and morphology of the iron oxide nanoparticles, but remarkably increases stability and Coulombic efficiency with respect to the anode based on the composite α-Fe2O3@rGO. For fixed rGO content, Ti-doping improves the rate capability at lower rates, whereas Mn-doping enhances the electrode stability at higher rates, retaining a specific capacity of 56 mAhg−1 at a rate of 2C. Nanocomposites with higher rGO content exhibit better electrochemical performance.

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Liu, Yu, Wei Wang, Xiaomin Xu, Jean-Pierre Marcel Veder et Zongping Shao. « Recent advances in anion-doped metal oxides for catalytic applications ». Journal of Materials Chemistry A 7, n^o 13 (2019) : 7280–300. http://dx.doi.org/10.1039/c8ta09913h.

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Susilawati, Susilawati, Aris Doyan, Lalu Muliyadi et Syamsul Hakim. « Growth of Tin Oxide Thin Film by Aluminum and Fluorine Doping Using Spin Coating Sol-Gel Techniques ». Jurnal Penelitian Pendidikan IPA 6, n^o 1 (14 octobre 2019) : 1. http://dx.doi.org/10.29303/jppipa.v6i1.264.

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Abstract: The growth of tin oxide thin film by Aluminum doping and Fluorine has been carried out with the sol-gel spin coating technique. The growth aims to determine the quality of the thin layer formed based on variations in doping aluminum and fluorine. The basic ingredients used were SnCl2.2H2O, while the doping materials used were Al (Aluminium) and F (Fluorine) with variations in dopant concentrations (0, 5, 10, 15, 20 and 25)%. The growth of a thin layer using measured glass (10x10x 3) mm as a substrate. The growth of thin films includes substrate preparation, sol-gel making, thin film making, and heating processes. The growth of thin layer was dripped on a glass substrate with sol-gel spin coating technique at 1 M sol concentration and treated with maturation for 24 hours. The next step is making a thin layer using a spin coater at a speed of 2000 rpm for 3 minutes. After that, the substrate is heated in an oven at 100°C for 60 minutes. The results showed that the transparency level of the tin oxide layer increases with increasing amounts of doping Aluminum and fluorine. Key words: Aluminum, Fluorine, Sol-gel, Spin Coating, Thin Film, Tin Oxide

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Doyan, Aris, Susilawati, Ahmad Harjono, Syifa Azzahra et Muhammad Taufik. « Characterization of TiN Oxide Doping Antimony Thin Layer with Sol- Gel Spin Coating Method for Electronic Device ». Materials Science Forum 966 (août 2019) : 30–34. http://dx.doi.org/10.4028/www.scientific.net/msf.966.30.

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Antimony tin oxide coating research has been carried out using a spin sol gel coating method with different doping concentrations (0, 5, 10, 15, 20)%. The results of the study on the morphological structure (SEM) of thin films that have been carried out showed more cracks on the surface of the morphology of thin layers without doping compared to thin layers with doping antimony. The Results of crystal structure of XRD in thin antimony doping tin oxide layer shows the grinding index of tin oxide crystals, 101, 110, 211, 220. In grain size, with increasing antimony doping percentage, the average grain size decreases. The optical properties using UV-Vis in thin films of antimony tin oxide doping show samples including semiconductor materials that can be used as electronic devices as seen from the reduction of this energy gap (3,680 - 3,574) eV. Also seen is an increase in the percentage of antimony doping and repetition of layers, the lower the transmissions value, but the value of absorbance of the thin layer increases.

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Ahmed, Sabah M. « Characterization of Al-doped ZnO nanorods grown by chemical bath deposition method ». Innovaciencia Facultad de Ciencias Exactas, Físicas y Naturales 6, n^o 1 (28 décembre 2018) : 1–9. http://dx.doi.org/10.15649/2346075x.463.

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Introduction: In recent years a metal oxide semiconductors have been paid attention due to their excellent chemical and physical properties. ZnO (Zinc oxide) is considered as one of the most attractive semiconductor materials for implementation in photo-detectors, gas sensors, photonic crystals, light emitting diodes, photodiodes, and solar cells, due to its novel electrical and optoelectronic properties. There are different uses of metal oxide semiconductors such us, UV photodetectors which are useful in space research’s, missile warning systems, high ﬂame detectors, air quality spotting, gas sensors, and precisely calculated radiation for the treatment of UV-irradiated skin. ZnO is a metal oxide semiconductors and it is used as a transparent conducting oxide thin ﬁlm because it has the best higher thermal stability, best resistance against the damage of hydrogen plasma processing and relatively cheaper if one compares it with ITO. Materials and Methods: On glass substrates, Al-doped ZnO (AZO) nanorods have been grown by a low -cost chemical bath deposition (CBD) method at low temperature. The seed layer of ZnO was coated on glass substrates. The effect of the Al-doping on the aligned, surface morphology, density, distribution, orientation and structure of ZnO nanorods are investigated. The Al-doping ratios are 0%, 0.2%, 0.8% and 2%. The Aluminum Nitrate Nonahydrate (Al (NO3)3.9H2O) was added to the growth solution, which is used as a source of the aluminum dopant element. The morphology and structure of the Al-doped ZnO nanorods are characterized by field emission scanning electron microscopy (FESEM) and high-resolution X-ray diffractometer (XRD). using the radio RF (Radio frequency) magnetron technique. Results and Discussion: The results show that the Al-doping have remarkable effects on the topography parameters such as diameter, distribution, alignment, density and nanostructure shape of the ZnO nanorods. These topography parameters have proportionally effective with increases of the Al-doping ratio. Also, X-ray diffraction results show that the Al-doping ratio has a good playing role on the nanostructure orientation of the ZnO nanorods. Conclusions: The Aluminum Nitride Nanohydrate considered as a good Aluminum source for doping ZnONR. It is clear from FESEM results that the Al-doping of ZnONR has a remarkable effect on the surface topography of nanorods for all aluminum doping ratios. From XRD patterns, it concludes that as the Al-doping ratio increases, the reorientation of the nanostructure of ZnO increases towards [100] direction. The results obtained also have shown that the average diameter of a nanorod is increased with increasing the ratio of Al-doping.

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Vini, K., et K. M. Nissamudeen. « Facile Combustion Synthesis of (Y,Pr)2O3 Red Phosphor : Study of Luminescence Dependence on Dopant Concentration and Enhancement by the Effect of Co-dopant ». Zeitschrift für Naturforschung A 75, n^o 4 (28 avril 2020) : 357–71. http://dx.doi.org/10.1515/zna-2019-0346.

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AbstractThere occurs a great interest in explaining the dependence of dopant concentration on the luminescence efficiency of rare earth oxides. Unambiguously, this study explains that luminescence intensity increases with increase in dopant concentration only up to optimised value. The syntheses of doped and co-doped yttrium oxide (Y2O3) nanophosphors in this study were carried out by making use of combustion method. This method produces the nanophosphors that have sizes ranging between 5 and 20 nm as confirmed by transmission electron microscopy. X-ray diffraction pattern confirms that the incorporation of praseodymium oxide (Pr3+) and gadolinium oxide (Gd3+) does not cause any change in the cubic structure of Y2O3. The phase purity has been confirmed by Fourier transform infrared spectrum. Diffuse reflectance spectra reveal that the bandgap increases with increase in annealing temperature. Bandgap has been calculated by making use of the Kubelka–Munk function. Strongest emission was observed at 605 nm with 2 wt% of Pr3+ as optimised concentration. Replacement of Y3+ by Gd3+ partially enhances the 605-nm emission linearly. The [Y:Pr:Gd] exhibits luminescence intensity of 2.705 times more than that of Y:Pr nanophosphors. This is for the first time our team has made a detailed study regarding the effects of co-doping in the case of Y2O3:Pr powders. We have successfully presented the changes that happen to the particle after co-doping especially in the particle size and luminescence properties.

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Koo, Bonjae, Jongsu Seo, Jun Kyu Kim et WooChul Jung. « Isovalent doping : a new strategy to suppress surface Sr segregation of the perovskite O2-electrode for solid oxide fuel cells ». Journal of Materials Chemistry A 8, n^o 27 (2020) : 13763–69. http://dx.doi.org/10.1039/d0ta02870c.

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Patra, Shanti Gopal, et Dan Meyerstein. « On the Mechanism of Heterogeneous Water Oxidation Catalysis : A Theoretical Perspective ». Inorganics 10, n^o 11 (26 octobre 2022) : 182. http://dx.doi.org/10.3390/inorganics10110182.

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Earth abundant transition metal oxides are low-cost promising catalysts for the oxygen evolution reaction (OER). Many transition metal oxides have shown higher OER activity than the noble metal oxides (RuO2 and IrO2). Many experimental and theoretical studies have been performed to understand the mechanism of OER. In this review article we have considered four earth abundant transition metal oxides, namely, titanium oxide (TiO2), manganese oxide/hydroxide (MnOx/MnOOH), cobalt oxide/hydroxide (CoOx/CoOOH), and nickel oxide/hydroxide (NiOx/NiOOH). The OER mechanism on three polymorphs of TiO2: TiO2 rutile (110), anatase (101), and brookite (210) are summarized. It is discussed that the surface peroxo O* intermediates formation required a smaller activation barrier compared to the dangling O* intermediates. Manganese-based oxide material CaMn4O5 is the active site of photosystem II where OER takes place in nature. The commonly known polymorphs of MnO2; α- (tetragonal), β- (tetragonal), and δ-(triclinic) are discussed for their OER activity. The electrochemical activity of electrochemically synthesized induced layer δ-MnO2 (EI-δ-MnO2) materials is discussed in comparison to precious metal oxides (Ir/RuOx). Hydrothermally synthesized α-MnO2 shows higher activity than δ-MnO2. The OER activity of different bulk oxide phases: (a) Mn3O4(001), (b) Mn2O3(110), and (c) MnO2(110) are comparatively discussed. Different crystalline phases of CoOOH and NiOOH are discussed considering different surfaces for the catalytic activity. In some cases, the effects of doping with other metals (e.g., doping of Fe to NiOOH) are discussed.

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Stub, Sindre Østby, Knut Thorshaug, Per Martin Rørvik, Truls Norby et Einar Vøllestad. « The influence of acceptor and donor doping on the protonic surface conduction of TiO2 ». Physical Chemistry Chemical Physics 20, n^o 23 (2018) : 15653–60. http://dx.doi.org/10.1039/c8cp00571k.

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Surface protonic transport in porous oxides is important for many catalytic and electrochemical applications and is altered by changing the acid–base properties of the oxide surface through aliovalent doping.

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GUO-LI, SONG. « LUMINESCENCE CHARACTERISTICS OF RARE-EARTH ERBIUM ION-DOPED NANOCRYSTALLINE ZINC OXIDE ». Journal of Nonlinear Optical Physics & ; Materials 18, n^o 04 (décembre 2009) : 649–56. http://dx.doi.org/10.1142/s0218863509004853.

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Er3+ -doped ZnO nanocrystalline powders are successfully prepared by the chemical precipitation method, using various doping concentrations of Er3+ at different annealing temperatures from 500°C to 900°C. The characteristic emission peaks of the excitation state 4S3/2 (550 nm), 2 H 11/2 (520 nm), 4 F 5/2 (455 nm) → 4 I 15/2 transition of Er3+ ions are observed in a wide visible band of the ZnO host. The relationship between the PL intensity of integration of nanocrystalline ZnO:Er3+ and the annealing temperature and doping concentration of Er3+ is given; it is found that the optimal dopant concentration and annealing temperature are 4.0 × 10-3 M and 850°C for the 4 S 3/2 → 4 I 15/2 (550 nm) and 4 F 5/2 → 4 I 15/2 (455 nm) transition of Er3+ . Based on these results, the mechanism of the emission spectra of ZnO is analyzed and its defects on the spectral properties are discussed. An energy transfer from excited states of ZnO hosts to doping Er3+ ion centers is revealed by the fact that PL intensity of the peaks of nanocrystalline ZnO:Er3+ changes with the annealing temperature and doping concentration of Er3+ , and another from the 4f–4f transition of Er3+ .

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Sun, Xi Lian, et Hong Tao Cao. « Effects of Nitrogen Doping on Optical Properties of Tungsten Oxide Thin Films ». Advanced Materials Research 616-618 (décembre 2012) : 1773–77. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.1773.

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In depositing nitrogen doped tungsten oxide thin films by using reactive dc pulsed magnetron sputtering process, nitrous oxide gas (N2O) was employed instead of nitrogen (N2) as the nitrogen dopant source. The nitrogen doping effect on the structural and optical properties of WO3 thin films was investigated by X-ray diffraction, transmission electron microscopy and UV-Vis spectroscopy. The thickness, refractive index and optical band gap energy of these films have been determined by analyzing the SE spectra using parameterized dispersion model. Morphological images reveal that the films are characterized by a hybrid structure comprising nanoparticles embeded in amorphous matrix and open channels between the agglomerated nanoparticles. Increasing nitrogen doping concentration is found to decrease the optical band gap energy and the refractive index. The reduced band gaps are associated with the N 2p orbital in the N-doped tungsten oxide films.

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Mahmoud, Arshad Ahmed, et Mohammad J.F. « Copper Doping Effect on Nanocrystalline Tin Oxide (SnO2) Thin Films for Gas Sensing Applications ». NeuroQuantology 20, n^o 5 (18 mai 2022) : 723–28. http://dx.doi.org/10.14704/nq.2022.20.5.nq22228.

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In this work, Nanocrystalline SnO2 and copper doped SnO2 with (SnO2:Cu, Cu: 1%, 3%, 5%) was grown on glass substrates at (350 °C) via chemical pyrolysis method. The results of the structural properties using XRD analysis showed that The films have diffraction angles of different intensities and have a tetragonal crystal structure. The intensity decreases with an increased doping ratio. Atomic force microscopy showed that with increasing copper doping, the average grain size decreased. Transmittance of the prepared films is greater than 70% at 550 nm. The energy gap of the calculated tin oxide is 3.9 eV and decreases with increasing copper doping, while the absorption coefficient increases with increasing Cu ratio.

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Syafnur, Zulfikri, et Elvaswer Elvaswer. « Karakteristik Arus-Tegangan Semikonduktor Copper Oxide Didoping dengan Zinc Oxide Sebagai Sensor Gas Hidrogen ». Jurnal Fisika Unand 6, n^o 2 (4 avril 2017) : 176–82. http://dx.doi.org/10.25077/jfu.6.2.176-182.2017.

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Telah dilakukan karakterisasi sensor gas hidrogen berupa pelet dengan bahan utama CuO yang didoping dengan ZnO. Pelet dibuat dengan variasi konsentrasi doping ZnO. Sensor gas hidrogen dibuat dengan menggunakan metode reaksi dalam keadaan padat. Sensor gas hidrogen diuji pada temperatur ruang dengan melihat karakteristik I-V, sensitivitas, konduktivitas, waktu respon, dan kristalinitas. Karakteristik I-V menunjukkan bahwa sampel dengan doping ZnO sebanyak 8% mol memiliki sensitivitas tertinggi yaitu 4,59 pada tegangan kerja 21 Volt. Nilai konduktivitas tertinggi dimiliki sampel CuO doping 2% mol ZnO yaitu 21,91 x 10-5/Ωm pada lingkungan hidrogen. Waktu respon sampel CuO didoping 8% mol ZnO adalah 45 s pada tegangan 21 Volt. Hasil XRD menunjukkan ukuran kristal CuO didoping 8% mol ZnO lebih besar dibandingkan dengan bahan CuO tanpa doping. Sensor gas hidrogen telah mampu membedakan kondisi di lingkungan hidrogen dengan kondisi di lingkungan udara, dengan sensitivitas yang tinggi dan waktu respon yang singkat. Sensor yang paling optimal digunakan adalah CuO didoping 8% mol ZnO.Kata kunci : sensor gas hidrogen, CuO, ZnO, sensitivitas, waktu respon

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Ngidi, Nonjabulo P. D., Moses A. Ollengo et Vincent O. Nyamori. « Effect of Doping Temperatures and Nitrogen Precursors on the Physicochemical, Optical, and Electrical Conductivity Properties of Nitrogen-Doped Reduced Graphene Oxide ». Materials 12, n^o 20 (16 octobre 2019) : 3376. http://dx.doi.org/10.3390/ma12203376.

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The greatest challenge in graphene-based material synthesis is achieving large surface area of high conductivity. Thus, tuning physico-electrochemical properties of these materials is of paramount importance. An even greater problem is to obtain a desired dopant configuration which allows control over device sensitivity and enhanced reproducibility. In this work, substitutional doping of graphene oxide (GO) with nitrogen atoms to induce lattice–structural modification of GO resulted in nitrogen-doped reduced graphene oxide (N-rGO). The effect of doping temperatures and various nitrogen precursors on the physicochemical, optical, and conductivity properties of N-rGO is hereby reported. This was achieved by thermal treating GO with different nitrogen precursors at various doping temperatures. The lowest doping temperature (600 °C) resulted in less thermally stable N-rGO, yet with higher porosity, while the highest doping temperature (800 °C) produced the opposite results. The choice of nitrogen precursors had a significant impact on the atomic percentage of nitrogen in N-rGO. Nitrogen-rich precursor, 4-nitro-ο-phenylenediamine, provided N-rGO with favorable physicochemical properties (larger surface area of 154.02 m2 g−1) with an enhanced electrical conductivity (0.133 S cm−1) property, making it more useful in energy storage devices. Thus, by adjusting the doping temperatures and nitrogen precursors, one can tailor various properties of N-rGO.

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Jiang, Man, Jing-Li Zhang, Fei Qiao, Rui-Ying Zhang, Ling-Bao Xing, Jin Zhou, Hongyou Cui et Shuping Zhuo. « Self-assembled reduced graphene hydrogels by facile chemical reduction using acetaldehyde oxime for electrode materials in supercapacitors ». RSC Advances 6, n^o 54 (2016) : 48276–82. http://dx.doi.org/10.1039/c6ra04348h.

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Self-assembled three-dimensional (3D) reduced graphene hydrogels (RGHs) were fabricated by the facile chemical reduction of a graphene oxide (GO) dispersion with ammonia using acetaldehyde oxime as reducing and doping agent.

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Siddharthan, R., P. Mahalingam, E. Kanagaraj et K. Saravanan. « Microwave Assisted Chemical Modification of Graphite Oxide for Supercapacitor Application ». Asian Journal of Chemistry 33, n^o 11 (2021) : 2621–25. http://dx.doi.org/10.14233/ajchem.2021.23346.

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In present work, graphite oxide was chemically modified with boron, nitrogen and sulfur co-doping in a simple, single step green method by microwave treatment. Borax, urea and thiourea were used as precursors for doping. Mixtures of graphite oxide with precursors were microwave treated using domestic microwave oven at 800 W for 5 min. The products obtained were characterized for its morphology, structure, composition and electrical properties. The results showed that simultaneous reduction of graphite oxide and doping of boron, nitrogen and sulfur were occurred. The elemental doping distorts the structure without much affecting the crystalline nature. The boron, nitrogen and sulfur elements were doped in graphite oxide to the extent of 9.97 at%, 2.67 at% and 0.84 at%, respectively. The cyclic voltammetry and electrochemical impedance spectroscopy studies showed that boron, nitrogen and sulfur co-doped graphite oxide could be a suitable material for supercapacitor application.

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Singh, Bhavana, S. B. Shrivastava et V. Ganesan. « Effects of Mn Doping on Zinc Oxide Films Prepared by Spray Pyrolysis Technique ». International Journal of Nanoscience 16, n^o 01 (février 2017) : 1650024. http://dx.doi.org/10.1142/s0219581x16500241.

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The work deals with the preparation of Zinc Oxide (ZnO) thin films on microscopic glass substrate by spray pyrolysis technique. The systematic study on the influence of Mn doping up to 15% has been performed. The structural studies revealed that pure and doped film has hexagonal structure. In order to reduce the internal strain due to Mn doping, the crystallite size decreases. The atomic force microscopy (AFM) measurement shows the decrease in grain size and roughness with doping. The resistivity curve shows a clear hump corresponding to smaller Mn doping ([Formula: see text]) around [Formula: see text]. This hump was found to reduce with the increase in Mn concentration and for [Formula: see text], beyond which it vanishes completely. This is attributed to critical behavior of resistivity and may be due to the scattering of carriers by magnetic spin fluctuation via exchange interaction. The optical measurement shows the shift in absorption edge of Mn doped ZnO films toward the longer wavelength side. This correlates the reduction in grain size as a function of Mn concentration. The optical bandgap goes down, whereas refractive index increases with dopant concentration.

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Seo, Juhyung, et Hocheon Yoo. « Remote Doping Effects of Indium–Gallium–Zinc Oxide Thin-Film Transistors by Silane-Based Self-Assembled Monolayers ». Micromachines 12, n^o 5 (23 avril 2021) : 481. http://dx.doi.org/10.3390/mi12050481.

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Oxide thin-film transistors (TFTs), including indium–gallium–zinc oxide (IGZO) TFTs, have been widely investigated because of their excellent properties, such as compatibility with flexible substrates, high carrier mobility, and easy-to-fabricate TFT processes. However, to increase the use of oxide semiconductors in electronic products, an effective doping method that can control the electrical characteristics of oxide TFTs is required. Here, we comprehensively investigate the effect of silane-based self-assembled monolayer (SAM) doping on IGZO TFTs. Instead of a complex doping process, the electrical performance can be enhanced by anchoring silane-based SAMs on the IGZO surface. Furthermore, differences in the doping effect based on the structure of SAMs were analyzed; the analysis offers a systematic guideline for effective electrical characteristic control in IGZO TFTs.

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Zhang, Weidong, Paola Anguita, Javier Díez-Ramírez, Claude Descorme, Jose Luis Valverde et Anne Giroir-Fendler. « Comparison of Different Metal Doping Effects on Co3O4 Catalysts for the Total Oxidation of Toluene and Propane ». Catalysts 10, n^o 8 (3 août 2020) : 865. http://dx.doi.org/10.3390/catal10080865.

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Metal-doped (Mn, Cu, Ni, and Fe) cobalt oxides were prepared by a coprecipitation method and were used as catalysts for the total oxidation of toluene and propane. The metal-doped catalysts displayed the same cubic spinel Co3O4 structure as the pure cobalt oxide did; the variation of cell parameter demonstrated the incorporation of dopants into the cobalt oxide lattice. FTIR spectra revealed the segregation of manganese oxide and iron oxide. The addition of dopant greatly influenced the crystallite size, strain, specific surface area, reducibility, and subsequently the catalytic performance of cobalt oxides. The catalytic activity of new materials was closely related to the nature of the dopant and the type of hydrocarbons. The doping of Mn, Ni, and Cu favored the combustion of toluene, with the Mn-doped one being the most active (14.6 × 10−8 mol gCo−1 s−1 at 210 °C; T50 = 224 °C), while the presence of Fe in Co3O4 inhibited its toluene activity. Regarding the combustion of propane, the introduction of Cu, Ni, and Fe had a negative effect on propane oxidation, while the presence of Mn in Co3O4 maintained its propane activity (6.1 × 10−8 mol gCo−1 s−1 at 160 °C; T50 = 201 °C). The excellent performance of Mn-doped Co3O4 could be attributed to the small grain size, high degree of strain, high surface area, and strong interaction between Mn and Co. Moreover, the presence of 4.4 vol.% H2O badly suppressed the activity of metal-doped catalysts for propane oxidation, among them, Fe-doped Co3O4 showed the best durability for wet propane combustion.

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Matsumoto, Y. « Solid oxide electrochemical doping (SOED) method ». Solid State Ionics 100, n^o 1-2 (septembre 1997) : 165–68. http://dx.doi.org/10.1016/s0167-2738(97)00310-x.

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El-Shobaky, G. A., G. A. Fagal, A. S. Ahmed et M. Mokhtar. « Physicochemical Surface and Catalytic Properties of the Na2O-doped CuO–ZnO/Al2O3 System ». Adsorption Science & ; Technology 16, n^o 2 (mars 1998) : 77–86. http://dx.doi.org/10.1177/026361749801600202.

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In order to investigate the effect of Na2O doping (0.75–4.5 mol%) on metal oxide-support interactions, the surface and catalytic properties of the CuO–ZnO/Al2O3 system have been studied using XRD, nitrogen adsorption at -196°C and the catalytic oxidation of CO by O2 at 150–200°C. Pure and doped mixed oxide solid samples were prepared via the wet impregnation method using Al(OH)3, NaNO3. Zn(NO3)2 and Cu(NO3)2 solutions, followed by drying and calcination at 600°C and 700°C.The nominal composition of the solids thus prepared was 0.25CuO:0.06ZnO: Al2O3. The results obtained showed that Na2O doping followed by heating in air at 600°C leads to enhanced crystallization of the CuO crystallites to an extent proportional to the amount of dopant present, while doping followed by heating in air at 700°C hinders the solid–solid interactions between CuO andA12O3, and leads to the production of CuAl2O4. The specific surface area was found to increase progressively as a function of the dopant concentration for the solid calcined at 700°C. The catalytic activity was also found to increase progressively on increasing the amount of dopant added. The maximum increase in the catalytic activity measured at 150, 175 and 200°C over solids calcined at 700°C was 114, 102 and 82%. respectively. The doping process did not modify the mechanism of the catalyzed reaction but rather increased the concentration of catalytically active constituents (surface CuO crystallites) involved in the chemisorption and catalysis of the CO oxidation reaction without affecting their energetic nature.

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Kamada, Kai, et Yasumichi Matsumoto. « Cation Doping of Oxide Ceramics Using Solid Oxide Electrochemical Doping : Evaluation of the SOED 2 Method ». Journal of Solid State Chemistry 146, n^o 2 (septembre 1999) : 406–10. http://dx.doi.org/10.1006/jssc.1999.8380.

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Bitay, Enikő, Irén Kacsó et Erzsébet Veress. « Chemical Durability of Uranium Oxide Containing Glasses ». Acta Materialia Transilvanica 1, n^o 1 (1 avril 2018) : 12–18. http://dx.doi.org/10.2478/amt-2018-0004.

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Abstract ZrO2 doped Na-Ba-borosilicate glasses suitable as matrix materials for HLW immobilization were synthesized and corrosion behaviour was investigated in different aqueous media. Hydrolytic stability is increased with the doping level until 5 mol %; above this value the glass vitrification tendency is strongly intensified. Unexpectedly, ZrO2 doping diminished the corrosion stability in 1M HCl solution, and low ZrO2 content showed a low corrosion resistance in 1M Na2CO3 solution also. Doping effect was negligible in case of synthetic seawater. The glass structure is significantly stabilized by the integration of the 30% UO3 added.

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Guilmeau, E., A. Maignan et C. Martin. « Thermoelectric Oxides : Effect of Doping in Delafossites and Zinc Oxide ». Journal of Electronic Materials 38, n^o 7 (28 avril 2009) : 1104–8. http://dx.doi.org/10.1007/s11664-009-0815-2.

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Malinovskaya, Tatyana D., Victor I. Sachkov, Valentina V. Zhek et Roman A. Nefedov. « Method for Determining the Doping Efficiency of Dispersed Semiconductor Metal Oxide Materials ». Key Engineering Materials 683 (février 2016) : 389–94. http://dx.doi.org/10.4028/www.scientific.net/kem.683.389.

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In this paper, a method for determining the doping efficiency of dispersed semiconductor metal oxide materials is proposed proposing to use the dependences of the free charge carrier concentration, normalized to the concentration of the doping impurity (Ne spec.), on the content of this impurity. The possibilities of this method are demonstrated by the example of studying the effect of technological factors on the efficiency of doping of indium oxide with tin and doping of tin oxide with antimony. It is shown that it is impossible to achieve the concentration of free charge carriers in the ITO material, higher than that in ATO materials, due to the lower solubility of tin in the In2O3 lattice, as compared with the solubility of antimony in the SnO2 lattice.

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Jeong, Donghwi, Junyoung Kim, Ohhun Kwon, Chaehyun Lim, Sivaprakash Sengodan, Jeeyoung Shin et Guntae Kim. « Scandium Doping Effect on a Layered Perovskite Cathode for Low-Temperature Solid Oxide Fuel Cells (LT-SOFCs) ». Applied Sciences 8, n^o 11 (11 novembre 2018) : 2217. http://dx.doi.org/10.3390/app8112217.

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Layered perovskite oxides are considered as promising cathode materials for the solid oxide fuel cell (SOFC) due to their high electronic/ionic conductivity and fast oxygen kinetics at low temperature. Many researchers have focused on further improving the electrochemical performance of the layered perovskite material by doping various metal ions into the B-site. Herein, we report that Sc3+ doping into the layered perovskite material, PrBaCo2O5+δ (PBCO), shows a positive effect of increasing electrochemical performances. We confirmed that Sc3+ doping could provide a favorable crystalline structure of layered perovskite for oxygen ion transfer in the lattice with improved Goldschmidt tolerance factor and specific free volume. Consequently, the Sc3+ doped PBCO exhibits a maximum power density of 0.73 W cm−2 at 500 °C, 1.3 times higher than that of PBCO. These results indicate that Sc3+ doping could effectively improve the electrochemical properties of the layered perovskite material, PBCO.

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