scholarly journals Time-Resolved Radiation-Induced Conductivity of Polyimide and Its Description Using the Multiple Trapping Formalism

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2061 ◽  
Author(s):  
Andrey Tyutnev ◽  
Vladimir Saenko ◽  
Aleksei Zhadov ◽  
Evgenii Pozhidaev
Keyword(s):  
Carrier Transport ◽  
Main Idea ◽  
Model Parameters ◽  
Mechanical And Thermal Properties ◽  
Current Sensing ◽  
Time Resolved ◽  
Multiple Trapping ◽  
Radiation Fluxes ◽  
Radiation Induced ◽  
Potential Decay

Polymer dielectrics subjected to intense radiation fluxes exhibit a radiation-induced conductivity (RIC). Polyimide is a good dielectric with excellent mechanical and thermal properties featuring high radiation resistance currently widely used in the spacecraft industry. Its RIC has been extensively studied in several laboratories. The purpose of the present study is to make a direct measurement of the RIC for both pulsed and continuous irradiation using a current sensing technique, which is contrary to the indirect method employing a surface-potential decay technique that is now preferred by spacecraft charging engineers. Our experiments are done in a small-signal regime excluding any recombination and dose effects. In combination with existing computer codes, we managed to develop further the conventional multiple trapping formalism and the RIC theory based on it. The main idea is to supplement an exponential trap distribution responsible for a dominant dispersive carrier transport in polymers with a small concentration of inherent deep traps which may or may not have an energy distribution. In line with this reasoning, we propose a tentative set of RIC model parameters for polyimide that accounts for the observed experimental data. The findings and their implications are discussed in a broad context of previous studies.

scholarly journals Radiation-Induced Transient Currents in Films of Poly(arylene ether ketone) Including Phthalide Moiety

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 13
Author(s):  
Evgenii D. Pozhidaev ◽  
Vera V. Shaposhnikova ◽  
Alexey R. Tameev ◽  
Andrey E. Abrameshin
Keyword(s):  
Electric Fields ◽  
Carrier Transport ◽  
Protective Coatings ◽  
Threshold Field ◽  
Electrostatic Discharges ◽  
Arylene Ether ◽  
Multiple Trapping ◽  
Radiation Induced ◽  
Ether Ketone ◽  
Semi Empirical

The electrical properties of thin films of poly(arylene ether ketone) copolymers (co-PAEKs) with a fraction of phthalide-containing units of 3, 5, and 50 mol% in the main chain were investigated by using radiation-induced conductivity (RIC) measurements. Transient current signals and current-voltage (I-V) characteristics were obtained by exposing 20 ÷ 25 μm thick films of the co-PAEKs to monoenergetic electron pulses with energy ranging from 3 to 50 keV in an electric field ranging from 5 to 40 V/μm. The Rose-Fowler-Vaisberg semi-empirical model based on a multiple trapping formalism was used for an analysis of the RIC data, and the parameters of the highly dispersive charge carrier transport were evaluated. The analysis revealed that charge carriers moved in isolation from each other, and the applied electric fields were below the threshold field triggering the switching effect (a reversible high-to-low resistivity transition) in the co-PAEK films. It was also found that the co-PAEK films, due to the super-linear I-V characteristics, are highly resistant to electrostatic discharges arising from the effects of ionizing radiation. This property is important for the development of protective coatings for electronic devices.

scholarly journals Radiation Induced Transient Currents in Films of Poly(Arylene Ether Ketone) Including Phthalide Moiety

2019 ◽  
Author(s):  
Evgenii Pozhidaev ◽  
Vera Shaposhnikova ◽  
Aleksey Tameev ◽  
Andrey Abrameshin
Keyword(s):  
Electric Fields ◽  
Carrier Transport ◽  
Protective Coatings ◽  
Threshold Field ◽  
Electrostatic Discharges ◽  
Arylene Ether ◽  
Multiple Trapping ◽  
Radiation Induced ◽  
Ether Ketone ◽  
Semi Empirical

Electrical properties of the thin films of poly(arylene ether ketone) copolymers (co-PAEKs) with the fraction of phthalide-containing units of 3, 5 and 50 mol% in the main chain were investigated by using radiation induced conductivity (RIC) measurements. Transient current signals and current-voltage (I-V) characteristics were obtained under exposing 20÷25 thick films of the co-PAEKs to monoenergetic electron pulses of the energy ranged from 3 to 50 keV in the electric field ranged from 5 to 40 V/μm. The Rose-Fowler-Vaisberg semi-empirical model based on a multiple trapping formalism was used for an analysis of the RIC data and the parameters of the highly dispersive charge carrier transport were evaluated. The analysis revealed that charge carriers moved in isolation from each other and the applied electric fields were below the threshold field triggering the switching effect (a reversible high-to-low resistivity transition) in the co-PAEK films. It was also found that the co-PAEK films due to the super-linear I-V characteristics are highly resistant to electrostatic discharges arising from the effects of ionizing radiation. This property is important for the development of protective coatings for electronic devices.

ТИРИСТОРНЫЙ ЭФФЕКТ В СВЧ ИС, ИЗГОТОВЛЕННЫХ ПО SIGE БИКМОП-ТЕХНОЛОГИЯМ

2020 ◽  
Vol 96 (3s) ◽  
pp. 612-614
Author(s):  
В.В. Елесина ◽  
И.О. Метелкин
Keyword(s):  
Integrated Circuits ◽  
Extraction Procedure ◽  
Compact Model ◽  
Model Parameters ◽  
Cad Systems ◽  
Parameters Extraction ◽  
Sige Bicmos ◽  
Bicmos Integrated Circuits ◽  
Basic Parameters ◽  
Radiation Induced

Проведен анализ случаев возникновения тиристорного эффекта в СВЧ ИС, изготовленных по технологии SiGe БиКМОП, при воздействии ионизирующего излучения. Рассмотрены области СВЧ ИС, чувствительные к возникновению ТЭ, определены основные параметры тиристорных структур. Проведена апробация подхода к восстановлению параметров схемно-топологической радиационно-ориентированной модели тиристорной структуры для САПР. The paper analyzes ionizing radiation induced latchup in microwave SiGe BiCMOS integrated circuits (ICs). Critical parts of ICs sensitive to latchup have been identified and basic parameters of corresponding parasitic thyristor structures have been determined. An approach has been approved to the thyristor structure compact model parameters extraction procedure intended for use in CAD systems.

Time-resolved Photoconductivity as a Probe of Carrier Transport in Microcrystalline Silicon

2006 ◽  
Vol 910 ◽  
Author(s):  
Steve Reynolds
Keyword(s):  
Density Of States ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Film Growth ◽  
Hole Mobility ◽  
Transport Parameters ◽  
Microcrystalline Silicon ◽  
Time Resolved ◽  
Transient Photoconductivity ◽  
Transport Measurements

AbstractThe use of transient photoconductivity techniques in the investigation of carrier transport in microcrystalline silicon is described. Results are presented which highlight variations in transport parameters such as carrier mobility and density of states with structure composition. Hole mobility is significantly enhanced by crystalline content in the film of 10% or less. The density of states inferred from transport measurements parallel to and at right angles to the direction of film growth differ somewhat, suggesting that transport may be anisotropic.

A study of the role of radiative ignition in the propagation of large explosions

1983 ◽  
Vol 385 (1789) ◽  
pp. 373-387 ◽  
Keyword(s):  
Flame Front ◽  
Large Scale ◽  
Critical Energy ◽  
Flame Speed ◽  
Minimum Size ◽  
Absolute Minimum ◽  
Radiation Fluxes ◽  
Radiation Induced ◽  
Vapour Cloud ◽  
Scale Turbulence

We consider the hypothesis that the anomalously high rates of propagation of unconfined vapour cloud explosions are caused, or aggravated, by radiation-induced multi-point ignition due to small particles ahead of the main flame front. The mechanism by which loose agglomerates of fine fibres ignite at very low radiation fluxes is examined and the measured dependence of ignition lag on the level of radiation provides the basis for calculating maximum flame speed enhancement. It is shown that, for compact particles, there is an absolute minimum size for radiative ignition due to vaporization below the minimum critical energy and that fibrous aggregates are more likely to be raised and dispersed by convection than any solid particle capable of inducing ignition. Modelling the growth of such flames for various densities of igniting particles displays the development in time of a convoluted flame front with greatly increased surface area and rate of burning, resembling in appearance the consequences of large-scale turbulence. The effective flame speeds are of the order required to account for observed levels of damage, even when no other enhancement is considered; in fact the mechanism suggests that interaction with other proposed causes of flame speed enhancement is highly probable

Comparative Study of Photocarrier Dynamics in CVD-deposited CuWO4, CuO, and WO3 Thin Films for Photoelectrocatalysis

2020 ◽  
Vol 234 (4) ◽  
pp. 699-717
Author(s):  
James Hirst ◽  
Sönke Müller ◽  
Daniel Peeters ◽  
Alexander Sadlo ◽  
Lukas Mai ◽  
...  
Keyword(s):  
Thin Films ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Terahertz Spectroscopy ◽  
Chemical Vapor ◽  
Photoelectrochemical Cells ◽  
Time Resolved ◽  
And Diffusion ◽  
Wo3 Thin Films ◽  
Carrier Transport Properties

AbstractThe temporal evolution of photogenerated carriers in CuWO4, CuO and WO3 thin films deposited via a direct chemical vapor deposition approach was studied using time-resolved microwave conductivity and terahertz spectroscopy to obtain the photocarrier lifetime, mobility and diffusion length. The carrier transport properties of the films prepared by varying the copper-to-tungsten stoichiometry were compared and the results related to the performance of the compositions built into respective photoelectrochemical cells. Superior carrier mobility was observed for CuWO4 under frontside illumination.

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