Topic
High-κ dielectric
About: High-κ dielectric is a research topic. Over the lifetime, 13219 publications have been published within this topic receiving 252147 citations. The topic is also known as: high-k dielectric.
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TL;DR: It is demonstrated that a very high energy density with fast discharge speed and low loss can be obtained in defect-modified poly(vinylidene fluoride) polymers by combining nonpolar and polar molecular structural changes of the polymer with the proper dielectric constants.
Abstract: Dielectric polymers with high dipole density have the potential to achieve very high energy density, which is required in many modern electronics and electric systems. We demonstrate that a very high energy density with fast discharge speed and low loss can be obtained in defect-modified poly(vinylidene fluoride) polymers. This is achieved by combining nonpolar and polar molecular structural changes of the polymer with the proper dielectric constants, to avoid the electric displacement saturation at electric fields well below the breakdown field. The results indicate that a very high dielectric constant may not be desirable to reach a very high energy density.
2,008 citations
TL;DR: In this paper, the Schottky barrier heights and band offsets for high dielectric constant oxides on Pt and Si were calculated and good agreement with experiment is found for barrier heights.
Abstract: Wide-band-gap oxides such as SrTiO3 are shown to be critical tests of theories of Schottky barrier heights based on metal-induced gap states and charge neutrality levels. This theory is reviewed and used to calculate the Schottky barrier heights and band offsets for many important high dielectric constant oxides on Pt and Si. Good agreement with experiment is found for barrier heights. The band offsets for electrons on Si are found to be small for many key oxides such as SrTiO3 and Ta2O5 which limit their utility as gate oxides in future silicon field effect transistors. The calculations are extended to screen other proposed oxides such as BaZrO3. ZrO2, HfO2, La2O3, Y2O3, HfSiO4, and ZrSiO4. Predictions are also given for barrier heights of the ferroelectric oxides Pb1−xZrxTiO3 and SrBi2Ta2O9 which are used in nonvolatile memories.
1,947 citations
TL;DR: In this article, the dielectric properties of isostructural compounds of the type A 2/3 Cu 3 Ti 4 O 12 (A =trivalent rare earth or Bi) have been presented.
Abstract: High dielectric constants have been found in oxides of the type A Cu 3 Ti 4 O 12 . The most exceptional behavior is exhibited by CaCu 3 Ti 4 O 12 , which shows a dielectric constant at 1 kHz of about 12,000 that is nearly constant from room temperature to 300°C. The cubic structure of these materials is related to that of perovskite (CaTiO 3 ), but the TiO 6 octahedra are tilted to produce a square planar environment for Cu 2+ . The CaCu 3 Ti 4 O 12 structure down to 35 K has been examined by neutron powder diffraction. The structure remains cubic and centric. Most compositions of the type A 2/3 Cu 3 Ti 4 O 12 ( A =trivalent rare earth or Bi) show dielectric constants above 1000. The dielectric properties of isostructural compounds of the type A Cu 3 Ti 3 FeO 12 are also presented.
1,825 citations
Book•
01 Dec 1995
TL;DR: Theory of dielectric measuring techniques and their applications as mentioned in this paper Theoretical and practical applications of die-lectric materials include: insulation strength of high pressure gases and of vacuum liquid dielectrics plastics as dielectors ceramics dielectrices in equipment, capacitors in capacitors rubber and plastics in cables problems of the cable engineer, and the requirements of the armed forces.
Abstract: Theory dielectric measuring techniques dielectric materials and their applications - dielectric materials insulation strengths of high pressure gases and of vacuum liquid dielectrics plastics as dielectrics ceramics dielectrics in equipment dielectrics in power and distribution equipment dielectrics in electronic equipment dielectrics in capacitors rubber and plastics in cables problems of the cable engineer dielectric materials as devices rectifiers piezoelectric transducers and resonators magnetic and dielectric amplifiers memory devices dielectric requirements of the armed forces tables of dielectric materials
1,614 citations
TL;DR: Optical conductivity measurements on the perovskite-related oxide CaCu3Ti4O12 provide a hint of the physics underlying the observed giant dielectric effect in this material, suggesting the presence of a strong absorption at very low frequencies due to dipole relaxation.
Abstract: Optical conductivity measurements on the perovskite-related oxide CaCu3Ti4O12 provide a hint of the physics underlying the observed giant dielectric effect in this material. A low-frequency vibration displays anomalous behavior, implying that there is a redistribution of charge within the unit cell at low temperature. At infrared frequencies (terahertz), the value for the dielectric constant is approximately 80 at room temperature, which is far smaller than the value of approximately 10(5) obtained at lower radio frequencies (kilohertz). This discrepancy implies the presence of a strong absorption at very low frequencies due to dipole relaxation. At room temperature, the characteristic relaxation times are fast (less than or approximately 500 nanoseconds) but increase dramatically at low temperature, suggesting that the large change in dielectric constant may be due to a relaxor-like dynamical slowing down of dipolar fluctuations in nanosize domains.
1,540 citations