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High piezoelectricity of BiScO3-PbTiO3 ceramics prepared by two step sintering
摘要： (1-x)BiScO3-xPbTiO3 (BSPT) ferroelectric ceramics were prepared by two-step sintering. Dielectric measurements in combination with diffraction contrast transmission electron microscopy (TEM) were used to confirm the phase diagram of BSPT system. From these results, the low temperature phase diagram for BSPT was achieved. In present study, high piezoelectric properties with piezoelectric coefficients (d33≈545pC/N, d33*≈920pm/V) and planar electromechanical coupling factor (kp ≈57%) are achieved in the ceramcs at the composition x=0.64, indicating a future high-temperature piezoelectric application.
关键词： Dielectrics,Phase diagram,Two step sintering,Ceramics
更新于2025-09-23 15:22:29
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[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Effective Microwave Electromagnetic Response of the Infinite Chain of Dielectric Coated Circular Metal Cylinders
摘要： Microwave approximations for effective electric and magnetic responses of the infinite chain have been obtained in this study. This infinite chain is comprised of long dielectric coated circular metal cylinders infinitely periodically space. The obtained approximations have been derived on the basis of the long wave approximation for the diffraction problem of a plane electromagnetic wave on the cylindrical chain using the Effective Medium Theory. Comparisons of the analytically obtained results with the numerically calculated ones have made in the study.
关键词： Artificial Dielectrics,Effective Medium Theory,Plane Wave Diffraction,Infinite Grating
更新于2025-09-23 15:21:21
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High-throughput ab initio calculations on dielectric constant and band gap of non-oxide dielectrics
摘要： High-k dielectrics, materials having a large band gap (Eg) and high dielectric constant (k) simultaneously, constitute critical components in microelectronic devices. Because of the inverse relationship between Eg and k, materials with large values in both properties are rare. Therefore, massive databases on Eg and k will be useful in identifying optimal high-k materials. While experimental and theoretical data on Eg and k of oxides are accumulating, corresponding information is scarce for non-oxide dielectrics with anions such as C, N, F, P, S, and Cl. To identify promising high-k dielectrics among these material groups, we screen 869 compounds of binary carbides, nitrides, sulfides, phosphides, chlorides, and fluorides, through automated ab initio calculations. Among these compounds, fluorides exhibit an Eg-k relation that is comparable to that of oxides. By further screening over ternary fluorides, we identify fluorides such as BiF3, LaF3, and BaBeF4 that could serve as useful high-k dielectrics.
关键词： band gap,dielectric constant,High-k dielectrics,non-oxide dielectrics,ab initio calculations
更新于2025-09-23 15:21:01
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<i>(Invited)</i> HfO <sub/>2</sub> /Al <sub/>2</sub> O <sub/>3</sub> Nanolaminate on Si <sub/>0.7</sub> Ge <sub/>0.3</sub> (100) Surface by Thermal Atomic Layer Deposition
摘要： To integrate Silicon-Germanium (SiGe) into future CMOS devices, it is essential to deposit very thin high-k dielectrics on SiGe surfaces with low density interfacial defects. In this study, Al2O3/HfO2 nanolaminate (HfO2 layers incorporated with Al2O3 monolayers) gate stacks were deposited by atomic layer deposition (ALD) using HfCl4 and H2O precursors. Electrical properties of the interfaces were quantified by capacitance-voltage (C–V) spectroscopy. Interfaces of nanolaminate stacks were found to have 2x smaller density of interface traps (Dit) than pure HfO2 gate stacks. Cross sectional TEM with Energy-dispersive X-ray spectroscopy (EDS) showed that an SiOx rich interlayer was formed between the nanolaminate and the Si0.7Ge0.3(001) substrate. The SiOx interlayer contains almost no Ge indicating that the HfCl4/TMA nanolaminate deposition reduced the GeOx in the interface. Furthermore, the SiGe surface was enriched in Ge from 30% to ~70% consistent with the HfCl4/TMA nanolaminate process reducing and redepositing Ge on the SiGe surface.
关键词： SiGe,atomic layer deposition,interface traps,high-k dielectrics,nanolaminate
更新于2025-09-23 15:21:01
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Perovskite Materials - Synthesis, Characterisation, Properties, and Applications || Microwave Dielectrics with Perovskite-Type Structure
摘要： Most electroceramics are ferroelectrics, but microwave dielectrics are mostly paraelectrics with a center of symmetry i. Microwave dielectrics should possess a perfect crystal structure with neither defects nor internal strain in order to be microwave friendly. They have been used in resonators and filters in mobile telecommunications devices. Perovskite and related compounds are also mostly ferroelectrics, but paraelectrics with a perovskite structure also exist, and are used in microwave dielectrics. Owing to the flexibility of the perovskite structure, many kinds of microwave dielectrics with a perovskite structure have been designed for microwave dielectrics. In this chapter, simple and complex perovskite, and perovskite related materials such as pseudo-tungsten-bronze solid solutions and homologous compounds are introduced for microwave dielectrics. The microwave dielectric properties are revealed through the crystalline structure of the material. Therefore, the relationship between the crystalline structure and properties of the material is presented, and is expected to be of use in the design of novel dielectrics. As many superior materials for microwave dielectrics have been developed and are expected to be used in new applications such as wireless sensors and wireless power transfer by resonant coupling, wave absorption by interference and transparent ceramics with no birefringence, these new applications are also discussed.
关键词： Tungsten-bronze compounds,Ordering,Homologous series,Microwave dielectrics,Complex Perovskite
更新于2025-09-23 15:21:01
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[Communications in Computer and Information Science] Advances in Computing and Data Sciences Volume 905 (Second International Conference, ICACDS 2018, Dehradun, India, April 20-21, 2018, Revised Selected Papers, Part I) || Assessing the Performance of CMOS Amplifiers Using High-k Dielectric with Metal Gate on High Mobility Substrate
摘要： With the increase in demand for high-performance ICs for both memory and logic applications, scaling has been continued down to 14 nm node. To meet the performance requirements, high-k dielectrics such as HfO2, ZrO2 have replaced SiO2 in the conventional MOS structure for sub-45 nm node. Correspondingly, the polysilicon gate electrode has been replaced by metal gate electrode in order to enable integration with high-k. Furthermore, the standard silicon substrate has been replaced by high mobility substrate in order to obtain desired transistor performance. While the fabrication technology for CMOS has advanced rapidly the traditional design tools used for designing circuits continues to use conventional MOS structure and their properties. This paper aims to analyze frequency response of CMOS common source ampli?er(CSA) and di?erential ampli?er by simulating in MATLAB using metal gate/high-k/Ge structure and to compare with traditionally used ampli?er design using standard MOS structure.
关键词： CMOS - Complementary Metal Oxide Semiconductor,EOT - E?ective Oxide Thickness,CSA - Common Source Ampli?er,UGB - Unity Gain Bandwidth,High-k dielectrics based ampli?er design
更新于2025-09-23 15:21:01
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Chemical and Biomolecule Sensing with Organic Field-Effect Transistors
摘要： The strong and controllable chemical sensitivity of organic semiconductors (OSCs) and the amplification capability of transistors in circuits make use of OSC-based field-effect transistors compelling for chemical sensors. Analytes detected and assayed range from few-atom gas-phase molecules that may have adverse health and security implications to biomacromolecules (proteins, nucleic acids) that may be markers for physiological processes and medical conditions. This review highlights recent progress in organic field-effect transistor (OFET) chemical sensors, emphasizing advances from the past 5 years and including aspects of OSC morphology and the role of adjacent dielectrics. Design elements of the OSCs and various formats for the devices are illustrated and evaluated. Challenges associated with the present state of the art and future opportunities are also discussed.
关键词： organic field-effect transistors,organic semiconductors,dielectrics,biomacromolecules,chemical sensors
更新于2025-09-23 15:21:01
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Optoplasmonics: basic principles and applications
摘要： Plasmonic and photonic elements often have complementary optical properties, motivating the development of ‘optoplasmonic’ hybrid systems in which the photonic and plasmonic elements can synergistically interact. The overall goal in the design of optoplasmonic structures is to overcome the limitations of the individual building blocks or to generate entirely new properties that reach beyond what is possible with conventional photonic or plasmonic structures. After providing a brief introduction into the relevant optical properties of plasmonic and photonic building blocks, this manuscript reviews optoplasmonic architectures that contain plasmonic nanoantennas embedded in a de?ned photonic environment generated by discrete dielectric nanoparticles (NPs), microcavities, waveguides, or photonic crystals, as well as all-metal NP or metal/dielectric NP hybrid arrays in which diffracted modes interact with the plasmons of metal NPs. The fundamental working principles of these optoplasmonic systems are analyzed and selected applications and fabrication strategies are discussed.
关键词： metamaterials,metasurface,sensing,hybrid materials,high refractive index dielectrics,plasmonics,nanophotonics
更新于2025-09-23 15:19:57
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Fabrication of Tapered Circular Depressed-Cladding Waveguides in Nd:YAG Crystal by Femtosecond-Laser Direct Inscription
摘要： Crystalline materials are excellent substrates for the integration of compact photonic devices bene?ting from the unique optical properties of these materials. The technique of direct inscription with femtosecond lasers, as an advantage over other techniques, has opened the door to the fabrication of true three-dimensional (3D) photonic devices in almost any transparent substrate. Depressed-cladding waveguides have been demonstrated to be an excellent and versatile platform for the integration of 3D photonic circuits in crystals. Here, we present the technique that we have developed to inscribe tapered depressed-cladding waveguides with a circular section for the control of the modal behavior. As a proof of concept, we have applied the technique to fabricate structures in Nd:YAG crystal that e?ciently change the modal behavior from highly multimodal to monomodal, in the visible and near infrared, with reduction factors in the waveguide radius of up to 4:1. Our results are interesting for di?erent devices such as waveguide lasers, frequency converters or connectors between external devices with di?erent core sizes.
关键词： femtosecond lasers,crystalline dielectrics,photonic device,micro-processing,waveguide
更新于2025-09-23 15:19:57
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The Integration of Photonic Crystal Waveguides with Atom Arrays in Optical Tweezers
摘要： Integrating nanophotonics and cold atoms has drawn increasing interest in recent years due to diverse applications in quantum information science and the exploration of quantum many-body physics. For example, dispersion-engineered photonic crystal waveguides (PCWs) permit not only stable trapping and probing of ultracold neutral atoms via interactions with guided-mode light, but also the possibility to explore the physics of strong, photon-mediated interactions between atoms, as well as atom-mediated interactions between photons. While diverse theoretical opportunities involving atoms and photons in 1D and 2D nanophotonic lattices have been analyzed, a grand challenge remains the experimental integration of PCWs with ultracold atoms. Here, an advanced apparatus that overcomes several significant barriers to current experimental progress is described, with the goal of achieving strong quantum interactions of light and matter by way of single-atom tweezer arrays strongly coupled to photons in 1D and 2D PCWs. Principal technical advances relate to efficient free-space coupling of light to and from guided modes of PCWs, silicate bonding of silicon chips within small glass vacuum cells, and deterministic, mechanical delivery of single-atom tweezer arrays to the near fields of photonic crystal waveguides.
关键词： atoms and nanophotonics,quantum simulation,quantum dielectrics,quantum information science
更新于2025-09-23 15:19:57