Journal articles: 'Single Crystalline Oxides'

1

Kim, Shin-Ik, Hyung-Jin Choi, Gwangyeob Lee, Chang Jae Roh, Inki Jung, Soo Young Jung, Ruiguang Ning, et al. "3D architectures of single-crystalline complex oxides." Materials Horizons 7, no. 6 (2020): 1552–57. http://dx.doi.org/10.1039/d0mh00292e.

Full text

Abstract:

We proposed 3D architectures of complex oxides as a way to derive novel properties: various 3D shapes were formed by self-shaped free-standing membranes, and curvature-induced polarization in an otherwise nonpolar material was observed.

APA, Harvard, Vancouver, ISO, and other styles

2

Peng, Bin, Ren-Ci Peng, Yong-Qiang Zhang, Guohua Dong, Ziyao Zhou, Yuqing Zhou, Tao Li, et al. "Phase transition enhanced superior elasticity in freestanding single-crystalline multiferroic BiFeO3 membranes." Science Advances 6, no. 34 (August 2020): eaba5847. http://dx.doi.org/10.1126/sciadv.aba5847.

Full text

Abstract:

The integration of ferroic oxide thin films into advanced flexible electronics will bring multifunctionality beyond organic and metallic materials. However, it is challenging to achieve high flexibility in single-crystalline ferroic oxides that is considerable to organic or metallic materials. Here, we demonstrate the superior flexibility of freestanding single-crystalline BiFeO3 membranes, which are typical multiferroic materials with multifunctionality. They can endure cyclic 180° folding and have good recoverability, with the maximum bending strain up to 5.42% during in situ bending under scanning electron microscopy, far beyond their bulk counterparts. Such superior elasticity mainly originates from reversible rhombohedral-tetragonal phase transition, as revealed by phase-field simulations. This study suggests a general fundamental mechanism for a variety of ferroic oxides to achieve high flexibility and to work as smart materials in flexible electronics.

APA, Harvard, Vancouver, ISO, and other styles

3

Glätzle, Matthias, Gregor J. Hoerder, and Hubert Huppertz. "RE2B8O15 (RE = La, Pr, Nd) – syntheses of three new rare earth borates isotypic to Ce2B8O15." Zeitschrift für Naturforschung B 71, no. 5 (May 1, 2016): 535–42. http://dx.doi.org/10.1515/znb-2016-0027.

Full text

Abstract:

AbstractThe rare earth borates RE2B8O15 (RE = La, Pr, Nd) were synthesized in a Walker-type multianvil apparatus under conditions of 5.5 GPa and 1100 °C. Starting from the corresponding rare earth oxides and boron oxide, the syntheses yielded crystalline products of all new compounds that allowed crystal structure analyses based on single-crystal X-ray diffraction data for La2B8O15 and Nd2B8O15. The compound Pr2B8O15 could be characterized via X-ray powder diffractometry. The results show that the new compounds crystallize isotypically to Ce2B8O15 in the monoclinic space group P2/c. The infrared spectra of RE2B8O15 (RE = La, Pr, Nd) have also been studied.

APA, Harvard, Vancouver, ISO, and other styles

4

Yeom, Eun Joo, Seong Sik Shin, Woon Seok Yang, Seon Joo Lee, Wenping Yin, Dasom Kim, Jun Hong Noh, Tae Kyu Ahn, and Sang Il Seok. "Controllable synthesis of single crystalline Sn-based oxides and their application in perovskite solar cells." Journal of Materials Chemistry A 5, no. 1 (2017): 79–86. http://dx.doi.org/10.1039/c6ta08565b.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Popescu, Madalina, Roxana Piticescu, Eugeniu Vasile, Dragos Taloi, Mirela Petriceanu, Maria Stoiciu, and Viorel Badilita. "The Influence of Synthesis Parameters on FeO(OH) / Fe2O3 Formation by Hydrothermal Techniques." Zeitschrift für Naturforschung B 65, no. 8 (August 1, 2010): 1024–32. http://dx.doi.org/10.1515/znb-2010-0808.

Full text

Abstract:

In this paper, a hydrothermal method of high-pressure and low-temperature synthesis conditions is presented as a simple single-step technique to obtain crystalline nanoparticles of iron oxides. The aim of this work has been to demonstrate the influence of the main synthesis parameters on the formation of nanosized Fe2O3 particles using statistical methods and to establish the most significant effects. Based on mathematical pre-modeling calculations, the best reaction conditions for the hydrothermal process have been chosen, and controlled crystalline nanostructures of iron oxides could be prepared

APA, Harvard, Vancouver, ISO, and other styles

6

Liu, Qing, Youwei Yan, Xiangcheng Chu, Yiling Zhang, Lihong Xue, and Wuxing Zhang. "Graphene-induced growth of single crystalline Sb2MoO6sheets and their sodium storage performance." J. Mater. Chem. A 5, no. 40 (2017): 21328–33. http://dx.doi.org/10.1039/c7ta07111f.

Full text

Abstract:

Pure and single crystalline Sb₂MoO₆sheets can be hydrothermally synthesizedviathe induction of graphene oxides, and the Sb₂MoO₆/RGO composite exhibits excellent cyclability and rate performance as the anode in a sodium ion battery.

APA, Harvard, Vancouver, ISO, and other styles

7

Chayasombat, Bralee, N. Tarumi, T. Kato, Tsukasa Hirayama, Katsuhiro Sasaki, and Kotaro Kuroda. "Transmission Electron Microscopy Studies of Oxidation of Single Crystal Silicon Carbide at High Temperature." Materials Science Forum 561-565 (October 2007): 2135–38. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.2135.

Full text

Abstract:

The microstructures of high-temperature oxide scales on the Si-terminated surface and C-terminated surface of 6H-SiC were investigated by transmission electron microscopy (TEM). We found that mechanical polishing caused surface strains, about 100 nm in depth, on both sides of specimens. Mechanically polished specimens were oxidized at 1473 K for 20 h in air. Oxide scales of about 250 nm in thickness were formed on the Si-terminated surface and of about 400 nm on the C-terminated surface. Since the strain regions caused by mechanical polishing were oxidized, strains were no longer observed. As a result, this oxidation condition effectively removed the strains. The oxide scales were identified as amorphous silica on the Si-terminated face, while crystalline oxides and amorphous silica were observed on the C-terminated face.

APA, Harvard, Vancouver, ISO, and other styles

8

QIAN, H. X., W. ZHOU, and H. Y. ZHENG. "RIPPLE FORMATION ON InP SURFACE IRRADIATED WITH FEMTOSECOND LASER." International Journal of Nanoscience 04, no. 04 (August 2005): 779–84. http://dx.doi.org/10.1142/s0219581x0500370x.

Full text

Abstract:

Single crystalline InP was ablated with linearly p-polarized femtosecond laser in air. Ripples with orientation parallel to the laser polarization direction were formed at low laser fluence. Analyses by EDX reveal In oxides and P oxides on the surface. Micro Raman spectroscopy of the laser irradiated surface indicates presence of stresses and possible formation of InP nanocrystals due to the femtosecond laser irradiation.

APA, Harvard, Vancouver, ISO, and other styles

9

Fomenko, V. S. "Electronic work function of sintered and single-crystalline high-temperature superconducting oxides." Powder Metallurgy and Metal Ceramics 32, no. 2 (February 1993): 178–81. http://dx.doi.org/10.1007/bf00560050.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Uhrmacher, Michael, and Klaus-Peter Lieb. "Phase Transitions in Oxides Studied by Perturbed Angular Correlation Spectroscopy." Zeitschrift für Naturforschung A 55, no. 1-2 (February 1, 2000): 90–104. http://dx.doi.org/10.1515/zna-2000-1-217.

Full text

Abstract:

Radioactive atoms located on cation sites in oxide matrices can be used to monitor phase transitions by measuring the electric or magnetic hyperfine interactions by means of Perturbed Angular Correlations spectroscopy. The article illustrates three types of phase transitions studied with 111In tracers and their daughter nuclei 111Cd, namely magnetic, structural and REDOX phase transitions in binary and ternary polycrystalline or single-crystalline oxides. In this context, we also discuss the question of identifying the probes' lattice site(s), the scaling of the Electric Field Gradients in oxides, the influence of the (impurity) probes themselves on the phase transitions, and the occurrence and mechanisms of dynamic interactions. Recent results on 111In in pure and Li-doped In2S3 will also be presented.

APA, Harvard, Vancouver, ISO, and other styles

11

Guo, D. Z., K. Yu-Zhang, A. Gloter, G. M. Zhang, and Z. Q. Xue. "Synthesis and characterization of tungsten oxide nanorods." Journal of Materials Research 19, no. 12 (December 1, 2004): 3665–70. http://dx.doi.org/10.1557/jmr.2004.0469.

Full text

Abstract:

Single crystalline nanorods (15–200 nm in diameter and hundreds nanometers in length) have been formed on the carbon-covered W wires by simple electric heating under a vacuum of 5 × 10−4 Pa. The chemical composition and crystalline structure of the nanorods were carefully investigated by various characterization techniques such as scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, energy dispersive x-ray spectroscopy and electron energy loss spectroscopy. After ruling out any possible existence of carbon nanotubes (CNTs), tungsten carbide, W–Fe alloying, and formation of other types of tungsten oxides, monoclinic W18O49 phase has been well identified. The mechanism of nanorod formation of sub-tungsten oxide (∼WO2.7 compared to WO3) will be discussed in relation to the sample preparation conditions.

APA, Harvard, Vancouver, ISO, and other styles

12

Yu, Feng, Yi Wang, Cong Guo, He Liu, Weizhai Bao, Jingfa Li, Panpan Zhang, and Faxing Wang. "Spinel LiMn2O4 Cathode Materials in Wide Voltage Window: Single-Crystalline versus Polycrystalline." Crystals 12, no. 3 (February 24, 2022): 317. http://dx.doi.org/10.3390/cryst12030317.

Full text

Abstract:

Single-crystal (SC) layered oxides as cathodes for Li-ion batteries have demonstrated better cycle stability than their polycrystalline (PC) counterparts due to the restrained intergranular cracking formation. However, there are rare reports on comparisons between single-crystal LiMn2O4 (SC-LMO) and polycrystalline LiMn2O4 (PC-LMO) spinel cathodes for Li-ion storage. In this work, the Li-ion storage properties of spinel LiMn2O4 single-crystalline and polycrystalline with similar particle sizes were investigated in a wide voltage window of 2–4.8 V vs. Li/Li+. The SC-LMO cathode exhibited a specific discharge capacity of 178 mA·h·g−1, which was a bit larger than that of the PC-LMO cathode. This is mainly because the SC-LMO cathode showed much higher specific capacity in the 3 V region (Li-ion storage at octahedral sites with cubic to tetragonal phase transition) than the PC-LMO cathode. However, unlike layered-oxide cathodes, the PC-LMO cathode displayed better cycle stability than the SC-LMO cathode. Our studies for the first time demonstrate that the phase transition-induced Mn(II) ion dissolution in the 3 V region rather than cracking formation is the limiting factor for the cycle performance of spinel LiMn2O4 in the wide voltage window.

APA, Harvard, Vancouver, ISO, and other styles

13

Heon, Jeon Byeong, Jeong Hoon Son, and Dong Sik Bae. "Synthesis and Characterization of TiO₂ Doped CeO₂ Nanopowders by a Hydrothermal Process." Journal of Nano Research 47 (May 2017): 49–53. http://dx.doi.org/10.4028/www.scientific.net/jnanor.47.49.

Full text

Abstract:

Hydrothermal processes have the potential for the direct preparation of crystalline ceramic powders and offer a low-temperature alternative to conventional powder synthesis techniques in the production of oxide powders. These processes can produce fine, high-purity, stoichiometric particles of single and multi-component metal oxides. Furthermore, if process conditions such as solute concentration, reaction temperature, reaction time and the type of solvent are carefully controlled, the desired shape and size of particles can be produced. Uniform distribution of the particles is key for optimal control of grain size and microstructure in order to maintain high reliability. It has been demonstrated that such powders are composed of much softer agglomerates and sinter much better than those prepared by calcination decomposition of the same oxides. These powders could be sintered at low temperature without calcination and milling steps. The objective of this study was to synthesis TiO2-CeO2 nanosized crystalline particles by a hydrothermal process.TiO2-CeO2 nanosized powders were prepared under high temperature and pressure conditions by precipitation from metal nitrates with aqueous potassium hydroxide. The TiO2-CeO2 nanosized powder was obtained at 185°C and 6 h. The average size and size distribution of the synthesized particles were below 10±5 nm and narrow, respectively. The XRD diffraction pattern shows that the synthesized particles were crystalline. This study has shown that the synthesis of TiO2-CeO2 nanosized crystalline particles is possible under hydrothermal conditions in aqueous solution.

APA, Harvard, Vancouver, ISO, and other styles

14

Ou, Limin, Shengheng Nong, Ruoxi Yang, Yaoying Li, Jinrong Tao, Pan Zhang, Haifu Huang, et al. "Multi-Role Surface Modification of Single-Crystalline Nickel-Rich Lithium Nickel Cobalt Manganese Oxides Cathodes with WO3 to Improve Performance for Lithium-Ion Batteries." Nanomaterials 12, no. 8 (April 12, 2022): 1324. http://dx.doi.org/10.3390/nano12081324.

Full text

Abstract:

Compared with the polycrystalline system, the single-crystalline ternary cathode material has better cycle stability because the only primary particles without grain boundaries effectively alleviate the formation of micro/nanocracks and retain better structural integrity. Therefore, it has received extensive research attention. There is no consistent result whether tungsten oxide acts as doping and/or coating from the surface modification of the polycrystalline system. Meanwhile, there is no report on the surface modification of the single-crystalline system by tungsten oxide. In this paper, multirole surface modification of single-crystalline nickel-rich ternary cathode material LiNi0.6Co0.2Mn0.2O2 by WO3 is studied by a simple method of adding WO3 followed by calcination. The results show that with the change in the amount of WO3 added, single-crystalline nickel-rich ternary cathode material can be separately doped, separately coated, and both doped and coated. Either doping or coating effectively enhances the structural stability, reduces the polarization of the material, and improves the lithium-ion diffusion kinetics, thus improving the cycle stability and rate performance of the battery. Interestingly, both doping and coating (for SC-NCM622-0.5%WO3) do not show a more excellent synergistic effect, while the single coating (for SC-NCM622-1.0%WO3) after eliminating the rock-salt phase layer performs the most excellent modification effect.

APA, Harvard, Vancouver, ISO, and other styles

15

WANG, ZHONG LIN, and ZHENGWEI PAN. "NANOBELTS OF SEMICONDUCTIVE OXIDES: A STRUCTURALLY AND MORPHOLOGICALLY CONTROLLED NANOMATERIALS SYSTEM." International Journal of Nanoscience 01, no. 01 (February 2002): 41–51. http://dx.doi.org/10.1142/s0219581x02000024.

Full text

Abstract:

We have developed a simple and economic technique for synthesis of one-dimensional nanobelt structures of semiconductive oxides such as ZnO, SnO 2, In 2 O 3, CdO, Ga 2 O 3 and PbO 2. The as-synthesized oxide nanobelts are pure, structurally uniform, single crystalline and most of them free from dislocations; they have a rectangular-like cross-section with typical widths of 30–300 nanometers, width-to-thickness ratios of 5–10 and lengths of up to a few millimeters. The belt-like morphology appears to be a unique and common structural characteristic for the family of semiconducting oxides with cations of different valence states and materials of distinct crystallographic structures. The nanobelts are structurally and morphologically controlled and they are intrinsic semiconductors, providing a new system after carbon nanotubes for a systematic understanding on dimensionally confined transport phenomena in functional oxides. They are also ideal building blocks for fabrication of nanoscale devices based on the integrity of individual nanobelts.

APA, Harvard, Vancouver, ISO, and other styles

16

Bartonickova, Eva, Jaroslav Cihlar, and Klara Castkova. "Microwave-assisted synthesis of bismuth oxide." Processing and Application of Ceramics 1, no. 1-2 (2007): 29–33. http://dx.doi.org/10.2298/pac0702029b.

Full text

Abstract:

Single phase and ultrafine bismuth oxide was synthesized via microwave-assisted hydrothermal synthesis. The effect of reaction parameters (temperature/pressure and pH) on the product phase composition and morphology was discussed. The transformation of bismuth hydroxide into bismuth oxide was controlled by pH value and it was accelerated by time and temperature. The phase composition of reaction products was strongly dependent on pH value. The amorphous products were obtained at acidic pH conditions and the crystalline single phase product ?-Bi2O3 phase was obtained at pH ?12. The particle size was reduced from micrometric to nanometric size in the presence of a chelating agent. The bismuth hydroxides into bismuth oxides transformation mechanism, consisting in polycondensation of Bi - OH bounds to Bi-O-Bi bridges and crystallization of Bi2O3, was proposed.

APA, Harvard, Vancouver, ISO, and other styles

17

Ebbinghaus, Stefan G., Rosiana Aguiar, Anke Weidenkaff, Stefan Gsell, and Armin Reller. "Topotactical growth of thick perovskite oxynitride layers by nitridation of single crystalline oxides." Solid State Sciences 10, no. 6 (June 2008): 709–16. http://dx.doi.org/10.1016/j.solidstatesciences.2007.03.011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Shao, Jian, Hao Liu, Kai Zhang, Yang Yu, Weichao Yu, Hanxuan Lin, Jiebin Niu, et al. "Emerging single-phase state in small manganite nanodisks." Proceedings of the National Academy of Sciences 113, no. 33 (August 1, 2016): 9228–31. http://dx.doi.org/10.1073/pnas.1609656113.

Full text

Abstract:

In complex oxides systems such as manganites, electronic phase separation (EPS), a consequence of strong electronic correlations, dictates the exotic electrical and magnetic properties of these materials. A fundamental yet unresolved issue is how EPS responds to spatial confinement; will EPS just scale with size of an object, or will the one of the phases be pinned? Understanding this behavior is critical for future oxides electronics and spintronics because scaling down of the system is unavoidable for these applications. In this work, we use La0.325Pr0.3Ca0.375MnO3 (LPCMO) single crystalline disks to study the effect of spatial confinement on EPS. The EPS state featuring coexistence of ferromagnetic metallic and charge order insulating phases appears to be the low-temperature ground state in bulk, thin films, and large disks, a previously unidentified ground state (i.e., a single ferromagnetic phase state emerges in smaller disks). The critical size is between 500 nm and 800 nm, which is similar to the characteristic length scale of EPS in the LPCMO system. The ability to create a pure ferromagnetic phase in manganite nanodisks is highly desirable for spintronic applications.

APA, Harvard, Vancouver, ISO, and other styles

19

Kudo, Kohei, Yasunari Hamazaki, Shinya Yamada, Satoshi Abo, Yoshihiro Gohda, and Kohei Hamaya. "Great Differences between Low-Temperature Grown Co2FeSi and Co2MnSi Films on Single-Crystalline Oxides." ACS Applied Electronic Materials 1, no. 11 (October 4, 2019): 2371–79. http://dx.doi.org/10.1021/acsaelm.9b00546.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Kato, Kazumi, Feng Dang, Ken-ichi Mimura, Yoshiaki Kinemuchi, Hiroaki Imai, Satoshi Wada, Minoru Osada, Hajime Haneda, and Makoto Kuwabara. "Nano-sized cube-shaped single crystalline oxides and their potentials; composition, assembly and functions." Advanced Powder Technology 25, no. 5 (September 2014): 1401–14. http://dx.doi.org/10.1016/j.apt.2014.02.006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Jesse, Stephen, Qian He, Andrew R. Lupini, Donovan N. Leonard, Mark P. Oxley, Oleg Ovchinnikov, Raymond R. Unocic, et al. "Atomic-Level Sculpting of Crystalline Oxides: Toward Bulk Nanofabrication with Single Atomic Plane Precision." Small 11, no. 44 (October 19, 2015): 5895–900. http://dx.doi.org/10.1002/smll.201502048.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Huang, Xiang Hong, Jun Qiao, and Qian Feng Zhang. "Structure and Thermo-Chemical Stability of Sr-Fe-Co-O Mixed Metal Oxides." Advanced Materials Research 549 (July 2012): 193–97. http://dx.doi.org/10.4028/www.scientific.net/amr.549.193.

Full text

Abstract:

SrFexCo0.5Oδ(x=0.5, 0.75, 1.0, 1.25) mixed metal oxides were synthesized by the citrate method. The structure and thermo-chemical stability of the obtained SrFexCo0.5Oδpowders were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results show that the SrFexCo0.5Oδpowders are composed of perovskite-type cubic structure at both room temperature and high temperature. The crystalline phases of the SrFexCo0.5Oδpowders are dependent on the content of Fe and SrFe0.5Co0.5O3, SrFe0.19Co081O2.78are the main crystalline phases. The powders have good thermo-chemical stability at elevated temperatures in helium, which is confirmed by an in-situ high-temperature X-ray diffraction. The SEM images show that the product of the SrFexCo0.5Oδ(x=0.5, 1.0) is composed of single grain, while other two samples consist of layer structures and some open porosities.

APA, Harvard, Vancouver, ISO, and other styles

23

Tian, Hua, Jun Hui He, and Lin Lin Liu. "A Novel Method for the Synthesis of Manganese Oxide Nanostructures in a Microemulsion." Advanced Materials Research 181-182 (January 2011): 485–88. http://dx.doi.org/10.4028/www.scientific.net/amr.181-182.485.

Full text

Abstract:

Microporous manganese oxide in the form of laminar octahedral compounds (birnessite) has been synthesized facilely in a microemulsion system consisting of benzyl alcohol (BA), sodium dodecyl sulfate (SDS) and water. BA also served as a reducing reagent in the formation of manganese oxides. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Braunauer-Emmett-Teller (BET) measurements. The experimental results indicated that the reaction duration, temperature, and weight ratio of BA/SDS/H2O played key roles in determining the final morophologies of manganese oxide nanomaterials and also in their crystalline phase. Lower process temperature, shorter reaction time and lower BA ratio in the microemulsion were favorable for the formation of birnessite single phase. Mn3O4 nanocrystals appeared at a relatively higher temperature and more BA amount.

APA, Harvard, Vancouver, ISO, and other styles

24

Zhang, H. B., J. Zhang, Y. C. Zhou, Y. W. Bao, and M. S. Li. "Synthesis of AlN nanowires by nitridation of Ti3Si0.9Al0.1C2 solid solution." Journal of Materials Research 22, no. 3 (March 2007): 561–64. http://dx.doi.org/10.1557/jmr.2007.0072.

Full text

Abstract:

This paper describes a new method to synthesize AlN nanowires by the nitridation of Ti3Si0.9Al0.1C2 solid solution. Single-crystalline AlN nanowires with the hexagonal wurtzite structure can be easily prepared using this method. In particular, the resulting AlN nanowires display a new growth orientation of 〈1011〉 besides 〈1000〉 and 〈0001〉. This work indicates that MN+1AXN compounds are promising raw reactants to synthesize one-dimensional (1D) nanostructures of nitrides and oxides.

APA, Harvard, Vancouver, ISO, and other styles

25

Wang, Z. L., Z. W. Pan, and Z. R. Dai. "Structures of Oxide Nanobelts and Nanowires." Microscopy and Microanalysis 8, no. 6 (December 2002): 467–74. http://dx.doi.org/10.1017/s1431927602010383.

Full text

Abstract:

We have recently reported the synthesis of one-dimensional nanobelt structures of ZnO, SnO2, In2O3, CdO, Ga2O3, and PbO2 by evaporating the desired commercial metal oxide powders at high temperatures (Science (2001), 291, 1947). The as-synthesized oxide nanobelts are pure, structurally uniform, single crystalline, and most of them free from dislocations. The beltlike morphology appears to be a unique and common structural characteristic for the family of semiconducting oxides. In the present article, we focus on the twin and stacking fault planar defects found in oxide nanobelts and nanowires although they are rarely observed. Some interesting and unique growth morphologies are presented to illustrate the roles played by surface energy and kinetics in growth. It is shown that the surfaces of the oxide nanobelts are enclosed by the low-index, low-energy crystallographic facets. The growth morphology is largely dominated by the growth kinetics.

APA, Harvard, Vancouver, ISO, and other styles

26

Laus, Gerhard, Alexander Schwärzler, Gino Bentivoglio, Michael Hummel, Volker Kahlenberg, Klaus Wurst, Elka Kristeva, et al. "Synthesis and Crystal Structures of 1-Alkoxy-3-alkylimidazolium Salts Including Ionic Liquids, 1-Alkylimidazole 3-oxides and 1-Alkylimidazole Perhydrates." Zeitschrift für Naturforschung B 63, no. 4 (April 1, 2008): 447–64. http://dx.doi.org/10.1515/znb-2008-0411.

Full text

Abstract:

AbstractFunctionalized quaternary imidazolium salts were prepared with the intention to obtain new ionic liquids (ILs). Thus, more than forty 3-alkoxy-1-alkylimidazolium salts, 3-alkoxy-1-alkyl-2-methylimidazolium salts, 1-methylimidazole 3-oxide and 1,2-dimethylimidazole 3-oxide as well as their salts, 1,3-dihydroxyimidazolium salts and 1,3-dihydroxy-2-methylimidazolium salts were synthesized and characterized by spectroscopy and, to a limited extent, by viscosity and conductivity measurements. Results of fourteen single crystal X-ray structure determinations are reported, among them also the parent compounds 1-hydroxyimidazole 3-oxide and 1-hydroxy-2-methylimidazole 3- oxide. Selective debenzylation of 1-benzyloxy-3-methyl imidazolium salts and mono-demethoxylation of 1,3-dimethoxyimidazolium salts were achieved by hydrogenolysis. In addition, a crystalline semiperhydrate of 1,2-dimethylimidazole was characterized. Furthermore, an addition compound of 1-methylimidazole 3-oxide with tris(2-thienyl)borane and a silver carbene complex derived from 1-benzyloxy-3-methylimidazolium hexafluorophosphate was crystallized and characterized.

APA, Harvard, Vancouver, ISO, and other styles

27

Gurvitch, M., A. T. Fiory, L. S. Schneemeyer, R. T. Cava, G. P. Espinosa, and J. V. Waszczak. "Resistivities of ceramic and single-crystalline superconducting oxides to 1100K: What do they tell us?" Physica C: Superconductivity 153-155 (June 1988): 1369–70. http://dx.doi.org/10.1016/0921-4534(88)90325-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Zachara, John M., James K. Fredrickson, Shu-Mei Li, David W. Kennedy, Steven C. Smith, and Paul L. Gassman. "Bacterial reduction of crystalline Fe (super 3+) oxides in single phase suspensions and subsurface materials." American Mineralogist 83, no. 11-12 Part 2 (December 1, 1998): 1426–43. http://dx.doi.org/10.2138/am-1997-11-1232.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Zachara, John M., James K. Fredrickson, Shu-Mei Li, David W. Kennedy, Steven C. Smith, and Paul L. Gassman. "Bacterial reduction of crystalline Fe (super 3+) oxides in single phase suspensions and subsurface materials." American Mineralogist 83, no. 11-12 Part 2 (December 1, 1998): 1426–43. http://dx.doi.org/10.2138/am-1998-11-1232.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Jirátová, Květa, Martin Čada, Iryna Naiko, Alina Ostapenko, Jana Balabánová, Martin Koštejn, Jaroslav Maixner, et al. "Plasma Jet Sputtering as an Efficient Method for the Deposition of Nickel and Cobalt Mixed Oxides on Stainless-Steel Meshes: Application to VOC Oxidation." Catalysts 13, no. 1 (December 30, 2022): 79. http://dx.doi.org/10.3390/catal13010079.

Full text

Abstract:

Hollow cathode plasma sputtering is an advantageous method of preparing catalysts in the form of thin oxide films on supports. Such catalysts are particularly suitable for processes such as catalytic total oxidation of volatile organic compounds (VOCs), representing an economically feasible and environmentally friendly method of VOC abatement. Catalysts with Ni:Co molar ratios of 1:4, 1:1, and 4:1 were prepared on stainless-steel meshes and compared with single-component Ni and Co oxide catalysts. The properties of the catalysts were characterized by EDX, SEM, powder XRD, temperature-programmed reduction (H2-TPR), Raman spectroscopy, and XPS. Powder XRD revealed the formation of various crystalline phases that were dependent on molar the Ni:Co ratio. NiO and Co3O4 were identified in the single-component Ni and Co oxide catalysts, whereas Ni-Co mixed oxides with a spinel structure, together with NiO, were found in the catalysts containing both Ni and Co. Raman spectra of the catalysts prepared at high working pressures showed a slightly lower intensity of bands, indicating the presence of smaller oxide particles. The TPR profiles confirmed the improved reducibility of the Ni-Co oxide catalysts compared to the single-component Ni and Co catalysts. Catalytic activity was investigated in the deep oxidation of ethanol and toluene, which were used as model volatile organic compounds. In ethanol oxidation, the activity of sputtered catalysts was up to 16 times higher than that of the commercial Cu-Mn oxide catalyst EnviCat® VOC-1544. The main benefits of the sputtered catalysts are the much lower content of Ni and Co oxides and a negligible effect of internal diffusion. Moreover, the process of plasma jet sputtering can be easily implemented on a large scale.

APA, Harvard, Vancouver, ISO, and other styles

31

Malowney, J., N. Mestres, X. Borrise, A. Calleja, R. Guzman, J. Llobet, J. Arbiol, T. Puig, X. Obradors, and J. Bausells. "Dual Function Polyvinyl Alcohol Based Oxide Precursors for Nanoimprinting and Electron Beam Lithography." MRS Proceedings 1547 (2013): 75–80. http://dx.doi.org/10.1557/opl.2013.679.

Full text

Abstract:

ABSTRACTOrdered arrays of crystalline complex oxides nanostructures were synthesized onto single crystal insulating substrates using aqueous polyvinyl alcohol based electron beam resist precursors. The irradiated zones are insoluble in water (negative-tone resist) due to the electron induced cross linking of polyvinyl alcohol. The subsequent high temperature treatment of the developed precursor samples leads to the formation of ordered arrays of nanodots for low irradiation doses. For high irradiation dosages, epitaxially and oriented nanowires are obtained. These same precursors were shown to be nanoimprintable on single crystal substrates. This allows for future dual processing of a single precursor film gaining nano-structuration from both electron beam and nanoimprint lithography methods.

APA, Harvard, Vancouver, ISO, and other styles

32

Yushchuk, S. I., S. O. Yuryev, and N. T. Pokladok. "Growing of Thick Single-Crystalline La-Substituted Yttrium-Iron Garnet Films with Reproducible Parameters." Ukrainian Journal of Physics 64, no. 3 (April 1, 2019): 245. http://dx.doi.org/10.15407/ujpe64.3.245.

Full text

Abstract:

Basic principles of growing the thick (35–60 мm) single-crystalline La-substituted yttrium-iron garnet (Y3−xLaxFe5O12, La :YIG) films with reproducible parameters have been formulated. La :YIG films are grown on gallium-gadolinium garnet (Gd3Ga5O12) substrates from a supercooled melt-solution (MS) consisting of Y2O3, La2O3, and Fe2O3 oxides and the PbO–B2O3 solvent. In order to minimize the implantation of Pb2+ ions into the films, which degrades the film quality, the epitaxy has to be performed at high temperatures and a low MS supercooling. It is found that, in order to maintain a constant growth rate of La :YIG films with reproducible parameters, a large MS mass (10–16 kg) has to be used, and the MS temperature has to be permanently lowered at a rate of 0.042 K/min.

APA, Harvard, Vancouver, ISO, and other styles

33

Michalak, Natalia, Zygmunt Miłosz, Gina Peschel, Mauricio Prieto, Feng Xiong, Paweł Wojciechowski, Thomas Schmidt, and Mikołaj Lewandowski. "Symmetry-Induced Structuring of Ultrathin FeO and Fe3O4 Films on Pt(111) and Ru(0001)." Nanomaterials 8, no. 9 (September 12, 2018): 719. http://dx.doi.org/10.3390/nano8090719.

Full text

Abstract:

Iron oxide films epitaxially grown on close-packed metal single crystal substrates exhibit nearly-perfect structural order, high catalytic activity (FeO) and room-temperature magnetism (Fe3O4). However, the morphology of the films, especially in the ultrathin regime, can be significantly influenced by the crystalline structure of the used support. This work reports an ultra-high vacuum (UHV) low energy electron/synchrotron light-based X-ray photoemission electron microscopy (LEEM/XPEEM) and electron diffraction (µLEED) study of the growth of FeO and Fe3O4 on two closed-packed metal single crystal surfaces: Pt(111) and Ru(0001). The results reveal the influence of the mutual orientation of adjacent substrate terraces on the morphology of iron oxide films epitaxially grown on top of them. On fcc Pt(111), which has the same mutual orientation of adjacent monoatomic terraces, FeO(111) grows with the same in-plane orientation on all substrate terraces. For Fe3O4(111), one or two orientations are observed depending on the growth conditions. On hcp Ru(0001), the adjacent terraces of which are ‘rotated’ by 180° with respect to each other, the in-plane orientation of initial FeO(111) and Fe3O4(111) crystallites is determined by the orientation of the substrate terrace on which they nucleated. The adaptation of three-fold symmetric iron oxides to three-fold symmetric substrate terraces leads to natural structuring of iron oxide films, i.e., the formation of patch-like magnetite layers on Pt(111) and stripe-like FeO and Fe3O4 structures on Ru(0001).

APA, Harvard, Vancouver, ISO, and other styles

34

Liu, Cong, Feng An, Paria S. M. Gharavi, Qinwen Lu, Junkun Zha, Chao Chen, Liming Wang, et al. "Large-scale multiferroic complex oxide epitaxy with magnetically switched polarization enabled by solution processing." National Science Review 7, no. 1 (October 8, 2019): 84–91. http://dx.doi.org/10.1093/nsr/nwz143.

Full text

Abstract:

Abstract Complex oxides with tunable structures have many fascinating properties, though high-quality complex oxide epitaxy with precisely controlled composition is still out of reach. Here we have successfully developed solution-based single-crystalline epitaxy for multiferroic (1-x)BiTi(1-y)/2FeyMg(1-y)/2O3–(x)CaTiO3 (BTFM–CTO) solid solution in large area, confirming its ferroelectricity at the atomic scale with strong spontaneous polarization. Careful compositional tuning leads to a bulk magnetization of 0.07 ± 0.035 μB/Fe at room temperature, enabling magnetically induced polarization switching exhibiting a large magnetoelectric coefficient of 2.7–3.0 × 10−7 s/m. This work demonstrates the great potential of solution processing in large-scale complex oxide epitaxy and establishes novel room-temperature magnetoelectric coupling in epitaxial BTFM–CTO film, making it possible to explore a much wider space of composition, phase, and structure that can be easily scaled up for industrial applications.

APA, Harvard, Vancouver, ISO, and other styles

35

Dong, Guohua, Suzhi Li, Mouteng Yao, Ziyao Zhou, Yong-Qiang Zhang, Xu Han, Zhenlin Luo, et al. "Super-elastic ferroelectric single-crystal membrane with continuous electric dipole rotation." Science 366, no. 6464 (October 24, 2019): 475–79. http://dx.doi.org/10.1126/science.aay7221.

Full text

Abstract:

Ferroelectrics are usually inflexible oxides that undergo brittle deformation. We synthesized freestanding single-crystalline ferroelectric barium titanate (BaTiO3) membranes with a damage-free lifting-off process. Our BaTiO3 membranes can undergo a ~180° folding during an in situ bending test, demonstrating a super-elasticity and ultraflexibility. We found that the origin of the super-elasticity was from the dynamic evolution of ferroelectric nanodomains. High stresses modulate the energy landscape markedly and allow the dipoles to rotate continuously between the a and c nanodomains. A continuous transition zone is formed to accommodate the variant strain and avoid high mismatch stress that usually causes fracture. The phenomenon should be possible in other ferroelectrics systems through domain engineering. The ultraflexible epitaxial ferroelectric membranes could enable many applications such as flexible sensors, memories, and electronic skins.

APA, Harvard, Vancouver, ISO, and other styles

36

Bruckner, Barbara, Peter Bauer, and Daniel Primetzhofer. "Neutralization of slow helium ions scattered from single crystalline aluminum and tantalum surfaces and their oxides." Surface Science 691 (January 2020): 121491. http://dx.doi.org/10.1016/j.susc.2019.121491.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Theerdhala, Sriharsha, Devendra Alhat, Satish Vitta, and D. Bahadur. "Synthesis of Shape Controlled Ferrite Nanoparticles by Sonochemical Technique." Journal of Nanoscience and Nanotechnology 8, no. 8 (August 1, 2008): 4268–72. http://dx.doi.org/10.1166/jnn.2008.an21.

Full text

Abstract:

Synthesis of magnetic iron oxides/ferrites in the nano scale by sonochemical synthesis has become prominent recently. This technique facilitates the synthesis of magnetic particles in the nano scale attributed to the hotspot mechanism arising due to acoustic cavitation induced chemical reaction. Generally volatile organometallic precursor compounds favoring the formation of fully amorphous particles have been used to synthesize various nano magnetic materials. We report here the synthesis of ultrafine, <10 nm magnetic iron oxide nanoparticles by sonochemical technique starting with a non-volatile precursor iron salt such as iron citrate which seems to favor the formation of semi crystalline/crystalline particles as the reaction takes place either in the interfacial region or in the bulk solution. Mono dispersed, ultra fine, ∼4 nm spherical shaped magnetic maghemite particles having a saturation magnetization of 58.2 emu/g and coercivity of 118 Oe were obtained at low values of pH, 10 while higher pH, 11–13 favored the formation of elongated, cylindrical, acicular particles with a reduced magnetization. The coercivity was also found to decrease with increasing pH, with it being 118 Oe at pH 10 and 3 Oe at pH 13. When the ultrasound amplitude/intensity was low, 38% heat treatment of the samples at 300 °C (at pH 10) was required to make them crystalline, while application of high intensity ultrasound, 50% amplitude served as a single step mechanism for obtaining crystalline maghemite particles. The maghemite particles obtained at a pH of 10 could find applications in information storage media.

APA, Harvard, Vancouver, ISO, and other styles

38

Konopatsky, Anton, Tatyana Teplyakova, Vadim Sheremetyev, Tamara Yakimova, Olga Boychenko, Marina Kozik, Dmitry Shtansky, and Sergey Prokoshkin. "Surface Modification of Biomedical Ti-18Zr-15Nb Alloy by Atomic Layer Deposition and Ag Nanoparticles Decoration." Journal of Functional Biomaterials 14, no. 5 (April 28, 2023): 249. http://dx.doi.org/10.3390/jfb14050249.

Full text

Abstract:

Superelastic biocompatible alloys attract significant attention as novel materials for bone tissue replacement. These alloys are often composed of three or more components that lead to the formation of complex oxide films on their surfaces. For practical use, it is desirable to have a single-component oxide film with a controlled thickness on the surface of biocompatible material. Herein we investigate the applicability of the atomic layer deposition (ALD) technique for surface modification of Ti-18Zr-15Nb alloy with TiO2 oxide. It was found that a 10–15 nm thick, low-crystalline TiO2 oxide layer is formed by ALD method over the natural oxide film (~5 nm) of the Ti-18Zr-15Nb alloy. This surface consists of TiO2 exclusively without any additions of Zr or Nb oxides/suboxides. Further, the obtained coating is modified by Ag nanoparticles (NPs) with a surface concentration up to 1.6% in order to increase the material’s antibacterial activity. The resulting surface exhibits enhanced antibacterial activity with an inhibition rate of more than 75% against E.coli bacteria.

APA, Harvard, Vancouver, ISO, and other styles

39

Dippong, Thomas, Erika Andrea Levei, Ioan Petean, Iosif Grigore Deac, Raluca Anca Mereu, and Oana Cadar. "Screening of Mono-, Di- and Trivalent Cationic Dopants for the Enhancement of Thermal Behavior, Kinetics, Structural, Morphological, Surface and Magnetic Properties of CoFe2O4-SiO2 Nanocomposites." International Journal of Molecular Sciences 24, no. 11 (June 2, 2023): 9703. http://dx.doi.org/10.3390/ijms24119703.

Full text

Abstract:

CoFe2O4 is a promising functional material for various applications. The impact of doping with different cations (Ag+, Na+, Ca2+, Cd2+, and La3+) on the structural, thermal, kinetics, morphological, surface, and magnetic properties of CoFe2O4 nanoparticles synthesized via the sol-gel method and calcined at 400, 700 and 1000 °C is investigated. The thermal behavior of reactants during the synthesis process reveals the formation of metallic succinates up to 200 °C and their decomposition into metal oxides that further react and form the ferrites. The rate constant of succinates’ decomposition into ferrites calculated using the isotherms at 150, 200, 250, and 300 °C decrease with increasing temperature and depend on the doping cation. By calcination at low temperatures, single-phase ferrites with low crystallinity were observed, while at 1000 °C, the well-crystallized ferrites were accompanied by crystalline phases of the silica matrix (cristobalite and quartz). The atomic force microscopy images reveal spherical ferrite particles covered by an amorphous phase, the particle size, powder surface area, and coating thickness contingent on the doping ion and calcination temperature. The structural parameters estimated via X-ray diffraction (crystallite size, relative crystallinity, lattice parameter, unit cell volume, hopping length, density) and the magnetic parameters (saturation magnetization, remanent magnetization, magnetic moment per formula unit, coercivity, and anisotropy constant) depend on the doping ion and calcination temperature.

APA, Harvard, Vancouver, ISO, and other styles

40

Figueiredo, J. F. D., V. Bouquet, S. Députier, O. Merdrignac-Conanec, I. Peron, E. P. Marinho, A. G. Souza, I. M. G. Santos, M. Guilloux-Viry, and I. T. Weber. "Zinc-gallium oxynitride powders: effect of the oxide precursor synthesis route." Cerâmica 59, no. 350 (June 2013): 269–76. http://dx.doi.org/10.1590/s0366-69132013000200012.

Full text

Abstract:

Zinc-gallium oxynitride powders (ZnGaON) were synthesized by nitridation of ZnGa2O4 oxide precursor obtained by polymeric precursors (PP) and solid state reaction (SSR) methods and the influence of the synthesis route of ZnGa2O4 on the final compound ZnGaON was investigated. Crystalline single phase ZnGa2O4 was obtained at 1100 ºC / 12 h by SSR and at 600 ºC / 2 h by PP with different grain sizes and specific surface areas according to the synthesis route. After nitridation, ZnGaON oxynitrides with a GaN würtzite-type structure were obtained in both cases, however at lower temperatures for PP samples. The microstructure and the specific surface area were strongly dependent on the oxide synthesis method and on the nitridation temperature (42 m²g-1 and 5 m²g-1 for PP and SSR oxides treated at 700 °C, respectively). The composition analyses showed a strong loss of Zn for the PP samples, favored by the increase of ammonolysis temperature and by the higher specific surface area.

APA, Harvard, Vancouver, ISO, and other styles

41

Sahana, M. B., and S. A. Shivashankar. "Metalorganic chemical vapor deposition of highly oriented thin film composites of V2O5 and V6O13: Suppression of the metal–semiconductor transition in V6O13." Journal of Materials Research 19, no. 10 (October 1, 2004): 2859–70. http://dx.doi.org/10.1557/jmr.2004.0394.

Full text

Abstract:

Thin films of vanadium oxides were grown on fused quartz by metalorganic chemical vapor deposition using vanadyl acetylacetonate as the precursor. Growth at temperatures ⩾560 °C results in composites of strongly (00l)-oriented V2O5 and V6O13. The dominant phase of the film changes from V2O5 to V6O13, and back to V2O5, as the growth temperature is raised from 560 to 570 °C, then to 580 °C, as evidenced by x-ray diffraction and Rutherford backscattering analyses. This reentrant-type growth trend was interpreted on the basis of the small difference in the free energy of formation of V2O5 and V6O13 and the presence of metal–oxygen bonds in the precursor. In contrast with single-crystalline V6O13, the film predominantly composed of highly oriented single-crystalline platelets of V6O13 did not undergo the semiconductor–metal transition at −123° K, despite the connectivity being well above the percolation threshold. Instead, a semiconductor-to-semiconductor transition was observed in this film, which is explained in terms of the observed relaxation of the edges of all the platelets of metallic V6O13 to semiconducting V2O5.

APA, Harvard, Vancouver, ISO, and other styles

42

Duan, Jun Hong, and Jian Xing Sun. "Controllable Synthesis of ZnO Nanostructures via Template-Free Electrochemical Deposition at Low Temperature and their Optical Properties." Advanced Materials Research 915-916 (April 2014): 540–44. http://dx.doi.org/10.4028/www.scientific.net/amr.915-916.540.

Full text

Abstract:

We report template-free electrochemical deposition method for preparing ZnO nanostructures arrays on indium tin oxides (ITO) glass substrate. Multiform ZnO nanostructures, such as nanotubes, nanorods with tower-like tips, cone-like tips and groove-like tips, are controllably synthesized at 60 °C, which is lower compared with the prepared temperatures of reported works. The results of XRD indicate the wurtzite ZnO nanostructures are single-crystalline and grow along the c-axis perpendicularly on the substrate. These findings have potential for the growth of high-quality ZnO nanostructures arrays and device applications.

APA, Harvard, Vancouver, ISO, and other styles

43

Xu, Xiaoshan, and Wenbin Wang. "Multiferroic hexagonal ferrites (h-RFeO3, R = Y, Dy-Lu): a brief experimental review." Modern Physics Letters B 28, no. 21 (August 20, 2014): 1430008. http://dx.doi.org/10.1142/s0217984914300087.

Full text

Abstract:

Hexagonal ferrites ( h - RFeO 3, R = Y , Dy - Lu ) have recently been identified as a new family of multiferroic complex oxides. The coexisting spontaneous electric and magnetic polarizations make h - RFeO 3 rare-case ferroelectric ferromagnets at low temperature. Plus the room-temperature multiferroicity and the predicted magnetoelectric effect, h - RFeO 3 are promising materials for multiferroic applications. Here we review the structural, ferroelectric, magnetic and magnetoelectric properties of h - RFeO 3. The thin film growth is also discussed because it is critical in making high quality single crystalline materials for studying intrinsic properties.

APA, Harvard, Vancouver, ISO, and other styles

44

Ghosh, Dipankar, Matthew T. Mulvee, and Krishna K. Damodaran. "Tuning Gel State Properties of Supramolecular Gels by Functional Group Modification." Molecules 24, no. 19 (September 25, 2019): 3472. http://dx.doi.org/10.3390/molecules24193472.

Full text

Abstract:

The factors affecting the self-assembly process in low molecular weight gelators (LMWGs) were investigated by tuning the gelation properties of a well-known gelator N-(4-pyridyl)isonicotinamide (4PINA). The N―H∙∙∙N interactions responsible for gel formation in 4PINA were disrupted by altering the functional groups of 4PINA, which was achieved by modifying pyridyl moieties of the gelator to pyridyl N-oxides. We synthesized two mono-N-oxides (INO and PNO) and a di-N-oxide (diNO) and the gelation studies revealed selective gelation of diNO in water, but the two mono-N-oxides formed crystals. The mechanical strength and thermal stabilities of the gelators were evaluated by rheology and transition temperature (Tgel) experiments, respectively, and the analysis of the gel strength indicated that diNO formed weak gels compared to 4PINA. The SEM image of diNO xerogels showed fibrous microcrystalline networks compared to the efficient fibrous morphology in 4PINA. Single-crystal X-ray analysis of diNO gelator revealed that a hydrogen-bonded dimer interacts with adjacent dimers via C―H∙∙∙O interactions. The non-gelator with similar dimers interacted via C―H∙∙∙N interaction, which indicates the importance of specific non-bonding interactions in the formation of the gel network. The solvated forms of mono-N-oxides support the fact that these compounds prefer crystalline state rather than gelation due to the increased hydrophilic interactions. The reduced gelation ability (minimum gel concentration (MGC)) and thermal strength of diNO may be attributed to the weak intermolecular C―H∙∙∙O interaction compared to the strong and unidirectional N―H∙∙∙N interactions in 4PINA.

APA, Harvard, Vancouver, ISO, and other styles

45

Huang, Jing-Kai, Yi Wan, Junjie Shi, Ji Zhang, Ya-Ping Chiu, Sean Li, and Lain-Jong Li. "(Invited, Digital Presentation) Heterogeneous Integration of Ultrahigh-Κ Single-Crystalline SrTiO₃ Membranes for Two-Dimensional Electronics." ECS Meeting Abstracts MA2022-02, no. 36 (October 9, 2022): 1315. http://dx.doi.org/10.1149/ma2022-02361315mtgabs.

Full text

Abstract:

Even though competitive 2D field-effect transistors (FETs) with the scaled channel dimensions have been demonstrated, it still is a challenge to integrate 2D semiconductors and high-κ dielectrics without deteriorating their interfaces, while decreasing capacitance equivalent thickness (CET) of dielectrics to maintain the gate controllability. In particular, the dielectric/channel interface is one of the predominant factors to affect device performance, including carrier mobility, switching behavior, and drifts of device parameters. This is often caused by the nature of dielectrics used, and the integrating methodologies applied. Typically, high-κ dielectrics used in silicon technology (i.e., Al2O3 and HfO2) are inherited by 2D FETs. The amorphous nature of these oxides makes the elimination of charge scattering and trapping sites at the dielectric/channel interfaces extremely difficult, not to mention that the direct deposition of dielectrics usually damages the 2D channel and results in poor uniformity in sheer thickness. Some interfacial passivation layers and processes have been developed, but they lead to thickening overall CET instead. Alternative approaches with the crystalline dielectric materials such as multilayer hBN and epitaxial calcium fluoride (CaF2), whose surfaces are well-constructed and atomic-flat, have demonstrated the competitive advantages of crystalline dielectric over the conventional amorphous oxides in spite of relatively lower κ values. Here, we demonstrate ultra-scaled 2D FETs with desirable sub-1 nm CET through heterogeneous integration of monolayer CVD MoS2 and quasi-2D single-crystalline SrTiO3 membranes, where the optimized SrTiO3 gate dielectrics exhibit a low gate leakage (J leak < 10-2 A/cm2 at 2.5 MV/cm). Typical transistors manifest good reliability and competitive performance characteristics, including steep subthreshold swings (SS) down to ~70 mV dec-1 and ON/OFF current ratios up to 107, matching low-power specifications suggested by the latest International Roadmap for Devices and Systems (IRDS). In addition, the van der Waals (vdW) interface between quasi-2D dielectrics and 2D semiconductors moderates the unfavorable fringing-induced barrier lowering (FIBL) effect occurring in ultra-scaled Si transistors with very high-κ dielectrics, which broadens the dielectric selection in 2D electronics for future technology node.

APA, Harvard, Vancouver, ISO, and other styles

46

Jannah, Ira Nur Arba’atul, Hanu Fiorena Sekarsari, Sri Mulijani, Karna Wijaya, Arief Cahyo Wibowo, and Aep Patah. "Facile Synthesis of Various ZrO2 Phases and ZrO2-MO2 (M = Ti, Hf) by Thermal Decomposition of a Single UiO-66 Precursor for Photodegradation of Methyl Orange." Catalysts 12, no. 6 (June 2, 2022): 609. http://dx.doi.org/10.3390/catal12060609.

Full text

Abstract:

A zirconia-based catalyst with controlled crystalline phases is synthesized through a simple thermal decomposition of a parent UiO-66 single precursor. The introduction of Ti(IV) and Hf(IV) cation into the Zr(IV) framework has been successfully obtained to tune the photocatalytic activity over methyl orange (MO) solution. Their resulting crystalline phases, morphologies, elemental analysis, band gap values, surface area, and photocatalytic degradation study over MO dye are presented and discussed. The tetragonal zirconia (t-ZrO2) catalyst exhibits the highest photocatalytic activity with 89% decoloration efficiency under UV irradiation (λ = 254 nm) for 300 min compared to m-ZrO2 (67%), the mixed phases (t-ZrO2 and m-ZrO2), as well as the synthesized mixed oxides ZrO2-MO2 (M = Ti or Hf), where the photocatalytic activities are 74% and 63%, respectively. This result is on par with commercially available anatase TiO2 and other reported t-ZrO2 catalysts.

APA, Harvard, Vancouver, ISO, and other styles

47

Ginsbach, A., G. Adrian, R. Schneider, G. Schulz, H. W. Grueninger, G. Grabe, and H. Adrian. "Electrical and structural properties of YBa2Cu3O7 films on poly and single crystalline oxides of Cu and Ni." Physica C: Superconductivity 185-189 (December 1991): 2111–12. http://dx.doi.org/10.1016/0921-4534(91)91180-c.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Varničić, Miroslava, Miroslav M. Pavlović, Sanja Eraković Pantović, Marija Mihailović, Marijana R. Pantović Pavlović, Srećko Stopić, and Bernd Friedrich. "Spray-Pyrolytic Tunable Structures of Mn Oxides-Based Composites for Electrocatalytic Activity Improvement in Oxygen Reduction." Metals 12, no. 1 (December 23, 2021): 22. http://dx.doi.org/10.3390/met12010022.

Full text

Abstract:

Hybrid nanomaterials based on manganese, cobalt, and lanthanum oxides of different morphology and phase compositions were prepared using a facile single-step ultrasonic spray pyrolysis (USP) process and tested as electrocatalysts for oxygen reduction reaction (ORR). The structural and morphological characterizations were completed by XRD and SEM-EDS. Electrochemical performance was characterized by cyclic voltammetry and linear sweep voltammetry in a rotating disk electrode assembly. All synthesized materials were found electrocatalytically active for ORR in alkaline media. Two different manganese oxide states were incorporated into a Co3O4 matrix, δ-MnO2 at 500 and 600 °C and manganese (II,III) oxide-Mn3O4 at 800 °C. The difference in crystalline structure revealed flower-like nanosheets for birnessite-MnO2 and well-defined spherical nanoparticles for material based on Mn3O4. Electrochemical responses indicate that the ORR mechanism follows a preceding step of MnO2 reduction to MnOOH. The calculated number of electrons exchanged for the hybrid materials demonstrate a four-electron oxygen reduction pathway and high electrocatalytic activity towards ORR. The comparison of molar catalytic activities points out the importance of the composition and that the synergy of Co and Mn is superior to Co3O4/La2O3 and pristine Mn oxide. The results reveal that synthesized hybrid materials are promising electrocatalysts for ORR.

APA, Harvard, Vancouver, ISO, and other styles

49

Stopyra, M., D. Niemiec, and G. Moskal. "Synthesis, Characterization and Thermal Diffusivity of Holmium and Praseodymium Zirconates." Archives of Metallurgy and Materials 61, no. 2 (June 1, 2016): 1249–54. http://dx.doi.org/10.1515/amm-2016-0206.

Full text

Abstract:

Abstract A2B2O7 oxides with pyrochlore or defected fluorite structure are among the most promising candidates for insulation layer material in thermal barrier coatings. The present paper presents the procedure of synthesis of holmium zirconate Ho2Zr2O7 and praseodymium zirconate Pr2Zr2O7 via Polymerized-Complex Method (PCM). Thermal analysis of precursor revealed that after calcination at relatively low temperature (700°C) fine-crystalline, single-phase material is obtained. Thermal diffusivity was measured in temperature range 25-200°C, Ho2Zr2O7 exhibits lower thermal diffusivity than Pr2Zr2O7. Additionally, PrHoZr2O7 was synthesized. The powder in as-calcined condition is single-phase, but during the sintering decomposition of solid solution took place and Ho-rich phase precipitated. This material exhibited the best insulating properties among the tested ones.

APA, Harvard, Vancouver, ISO, and other styles

50

Vasilopoulou, Maria, Ermioni Polydorou, Antonios M. Douvas, Leonidas C. Palilis, Stella Kennou, and Panagiotis Argitis. "Annealing-free highly crystalline solution-processed molecular metal oxides for efficient single-junction and tandem polymer solar cells." Energy & Environmental Science 8, no. 8 (2015): 2448–63. http://dx.doi.org/10.1039/c5ee01116g.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Single Crystalline Oxides'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles