Nanocarbon broadband analysis, temperature dependent dielectric properties and percolation thresholds

2013 ◽  
Author(s):  
S. Bellucci ◽  
J. Macutkevic ◽  
P. P. Kuzhir ◽  
A. Paddubskaya ◽  
S. A. Maksimenko ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Temperature Dependent ◽  
Percolation Thresholds

scholarly journals Tetragonal–Cubic Phase Transition and Low-Field Dielectric Properties of CH3NH3PbI3 Crystals

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4215
Author(s):  
Roxana E. Patru ◽  
Hamidreza Khassaf ◽  
Iuliana Pasuk ◽  
Mihaela Botea ◽  
Lucian Trupina ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Current Knowledge ◽  
Cubic Phase ◽  
Relaxation Processes ◽  
Temperature Dependent ◽  
Thermally Activated ◽  
Low Field ◽  
Conduction Mechanisms ◽  
Temperature Ranges ◽  
Nyquist Plots

The frequency and temperature dependence of dielectric properties of CH3NH3PbI3 (MAPI) crystals have been studied and analyzed in connection with temperature-dependent structural studies. The obtained results bring arguments for the existence of ferroelectricity and aim to complete the current knowledge on the thermally activated conduction mechanisms, in dark equilibrium and in the presence of a small external a.c. electric field. The study correlates the frequency-dispersive dielectric spectra with the conduction mechanisms and their relaxation processes, as well as with the different transport regimes indicated by the Nyquist plots. The different energy barriers revealed by the impedance spectroscopy highlight the dominant transport mechanisms in different frequency and temperature ranges, being associated with the bulk of the grains, their boundaries, and/or the electrodes’ interfaces.

PERMITTIVITY IN PERTURBED MOLECULAR NANOFILMS

2012 ◽  
Vol 26 (15) ◽  
pp. 1250078 ◽  
Author(s):  
BRANKO MARKOSKI ◽  
JOVAN P. ŠETRAJČIĆ ◽  
MIROSLAVA PETREVSKA ◽  
SINIŠA VUČENOVIĆ
Keyword(s):  
Optical Properties ◽  
Dielectric Properties ◽  
Green's Functions ◽  
Green’S Functions ◽  
Microscopic Theory ◽  
2D Systems ◽  
Molecular Films ◽  
Temperature Dependent

A microscopic theory of dielectric properties of thin molecular films, i.e., quasi 2D systems bounded by two surfaces parallel to XY planes was formulated. Harmonic exciton states were calculated using the method of two-time, retarded, temperature dependent Green's functions. It has been shown that two types of excitations can occur: bulk and surface exciton states. Analysis of the optical properties of these crystalline systems for low exciton concentration shows that the permittivity strongly depends on boundary parameters and the thickness of the film. Conditions for the appearance of localized or unoccupied exciton states have been especially analyzed.

Improvement of Dielectric Performance of a Prototype AlN High Temperature Chip-level Package

2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000052-000057 ◽  
Author(s):  
Liang-Yu Chen
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
High Temperatures ◽  
Substrate Surface ◽  
Substrate Material ◽  
Glass Coating ◽  
Temperature Dependent ◽  
High Temperature Electronics ◽  
Dielectric Performance ◽  
Parasitic Parameters

Aluminum nitride (AlN) has been proposed as a packaging substrate material for reliable high temperature electronics operating in a wide temperature range. However, it was discovered in a recent study that the dielectric properties of some commercial polycrystalline AlN materials change quite significantly with temperature at high temperatures. These material properties resulted in undesired large and temperature-dependent parasitic parameters for a prototype chip-level package based on an AlN substrate with the yttrium oxide dopant. This paper reports a method using a coating layer of a commercial thick-film glass on the AlN substrate surface to significantly reduce both the parasitic capacitances and parasitic conductances between neighboring inputs/outputs (I/Os) of a prototype AlN chip-level package. The parasitic parameters of 8-I/Os low power chip-level packages with the insulating glass coating were characterized at frequencies from 120 Hz to 1 MHz between room temperature and 500°C. These results were compared with the parameters of AlN packages without the glass coating. The results indicate that the parasitic capacitances and conductances between I/Os of the improved prototype AlN packages are significantly reduced and stable at high temperatures. The method using a glass coating provides a feasible way to mitigate the temperature dependence of dielectric properties of AlN and further utilize AlN as a reliable packaging substrate material for high temperature applications.

Temperature dependent dielectric properties of (na, K) NbO3, near equimolar composition

2019 ◽  
Vol 45 (10) ◽  
pp. 13067-13071 ◽  
Author(s):  
Surendra Singh ◽  
Jyotsana Negi ◽  
N.S. Panwar
Keyword(s):  
Dielectric Properties ◽  
Temperature Dependent ◽  
Equimolar Composition
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