Investigation of piezoelectricity distributions in poly(vinylidene fluoride) by means of quartz- or laser-generated pressure pulses

Gerhard-Multhaupt, Reimund; Sessler, G. M.; West, James E.; Holdik, Karl; Haardt, Martin; Eisenmenger, Wolfgang

doi:10.1063/1.333284

Cited by 85 publications

(6 citation statements)

References 27 publications

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“…Based on different forms of pressure wave induction, the PWP can be divided into two categories, i.e., piezoelectric-induced pressure wave propagation method and laser induced pressure pulse method. [111][112][113] The PEA method was developed in 1987 by Takada et al [114] Under a high-voltage pulsed electric field, the space charge will shift slightly and generate an acoustic impulse. Once the pulse passes through the sample and reaches the bottom electrode, the acoustic signal can be converted into an electrical signal by a piezoelectric transducer.…”

Section: Acoustic Methodsmentioning

confidence: 99%

Space Charge Behavior in Epoxy‐Based Dielectrics: Progress and Perspective

Liu

Xie

et al. 2022

Adv Elect Materials

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temperature and complex electric field conditions. [1][2][3] Epoxy resin (EP) is a class of polymer oligomers containing two or more epoxide groups based on organic compounds (e.g., aliphatic, alicyclic, and aromatic). As a prepolymer, EP shows excellent performance after its reaction with a curing agent to form an insoluble polymer with a 3D network structure. EP has desirable insulating characteristics, [4][5][6][7] heat resistance, [8] high mechanical strength, [9] low shrinkage, [10] chemical stability, and adhesive properties, which originate from its compact structure and tunable functional groups. The above mentioned outstanding performances, along with characteristics of easy processing and formula design flexibility, enable the extensive use of EP-based materials in power equipment and electronic devices [11] (Figure 1), including bar insulation and impregnating varnish in transformers, main insulation in dry-type bushings and wall bushings, insulator in gas-insulated switchgear (GIS) and gas-insulated transmission line (GIL), epoxy molding compound for integrated circuit (IC) packaging. It is noteworthy that EPs typically possess lower glass transition temperature (T g ) compared to other high-T g dielectric polymer substitutes used in microelectronic systems such as benzocyclobutene, [12] polyimide (PI), [13] and maleimide. [14] Besides high T g , high thermal conductivity and low coefficient of thermal expansion of EPs are always desired for their industrial applications, especially from an electronic packaging perspective. To date, considerable efforts have been made to improve the heat endurance and heat dissipation capabilities of EP-based dielectric materials by inorganic particle doping [15][16][17][18][19][20][21][22][23][24] and chemical modification. [25][26][27] Furthermore, EP is also an indispensable adhesive that is extensively used in power equipment. [28][29][30][31][32] Yet, potential reliability hazards may exist during the operation of power equipment and electronic devices, especially at high temperatures and under high voltage direct current (HVDC) application, one of which is the space charge accumulation in EP-based dielectric materials. [29,30,33,34] The accumulated space charge may cause deterioration/aging and even partial discharge or dielectric breakdown of dielectric materials. [35][36][37][38][39][40] Specifically, the extensive application of EP-based dielectric materials in HVDC transmission projects eagerly calls for relevant studies on the space charge behavior Epoxy-based dielectrics are extensively used in grid-connected energy systems and modern microelectronics as electrical insulation, adhesive, and packaging components. However, space charge accumulation in epoxy-based dielectrics is a foremost factor threatening device stability and lifespan, especially under conditions of high voltage direct current and high temperatures during long-term operation, and thus are investigated systematically. This article reviews the state-of-the-art progress in understanding and r...

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Section: Acoustic Methodsmentioning

confidence: 99%

Space Charge Behavior in Epoxy‐Based Dielectrics: Progress and Perspective

Liu

Xie

et al. 2022

Adv Elect Materials

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“…11). In the last case the evident maxima displacement to yellow-orange region may be explained by nonstoichiometry of chemical composition in transition area [25]. As-deposited ZnO films have polycrystalline structure.…”

Section: Pemocvd Deposition Of Piezoelectric and Transparent Electrocmentioning

confidence: 98%

Zinc oxide – analogue of GaN with new perspective possibilities

Karpina

Лазоренко

Lashkarev³

et al. 2004

Cryst. Res. Technol.

148

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Zinc oxide due to specific electrical, optical and acoustic properties is the important semiconductor material, which has many various applications. There is growing interest in ZnO due to its potential applicability for optoelectronic devices such as light-emitting diodes, laser diodes and detectors for UV wavelength range. ZnO properties are very close to those of widely recognized semiconductor GaN. The band gap of ZnO (3.37 eV) is close to that of GaN (3.39 eV) but ZnO exciton binding energy (60 meV) is twice larger than that of GaN (28 meV). Optically pumped UV lasing have been demonstrated at room temperature using high textured ZnO films. The excitonic gain close to 300 cm -1 was achieved. ZnO thin films are expected to have higher quantum efficiency in UV semiconductor laser than GaN. The physical properties of ZnO are considered. PEMOCVD technology was used to deposit piezoelectric and highly transparent electroconductive ZnO films. Their properties are discussed. The experiments on polycrystalline ZnO films deposited by RF magnetron sputtering at different partial pressure of oxygen are presented. AFM images were studied in tapping mode for deposited films. The investigated films were dielectric ones and had optical transparency within 65-85% at thickness in the interval 0.2-0.6 µm.

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“…-Various techniques can be used to generate a short rise time pressure wave. Presently, they have involved shock wave tubes [1,8], the discharge of condensers in fluids [9], the use of piezoelectric transducers [6,10] and the use of short rise time laser pulses [3,4,7,[10][11][12][13].…”

Section: Methodsmentioning

confidence: 99%