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Journal articles on the topic 'Bulk electrical conduction'

Author: Grafiati
Published: 4 June 2021
Last updated: 17 February 2022

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1

Semenenko, Bogdan, and Pablo Esquinazi. "Diamagnetism of Bulk Graphite Revised." Magnetochemistry 4, no. 4 (November 22, 2018): 52. http://dx.doi.org/10.3390/magnetochemistry4040052.

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Recently published structural analysis and galvanomagnetic studies of a large number of different bulk and mesoscopic graphite samples of high quality and purity reveal that the common picture assuming graphite samples as a semimetal with a homogeneous carrier density of conduction electrons is misleading. These new studies indicate that the main electrical conduction path occurs within 2D interfaces embedded in semiconducting Bernal and/or rhombohedral stacking regions. This new knowledge incites us to revise experimentally and theoretically the diamagnetism of graphite samples. We found that the c-axis susceptibility of highly pure oriented graphite samples is not really constant, but can vary several tens of percent for bulk samples with thickness t ≳ 30 μ m, whereas by a much larger factor for samples with a smaller thickness. The observed decrease of the susceptibility with sample thickness qualitatively resembles the one reported for the electrical conductivity and indicates that the main part of the c-axis diamagnetic signal is not intrinsic to the ideal graphite structure, but it is due to the highly conducting 2D interfaces. The interpretation of the main diamagnetic signal of graphite agrees with the reported description of its galvanomagnetic properties and provides a hint to understand some magnetic peculiarities of thin graphite samples.
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2

Chiu, Fu-Chien. "A Review on Conduction Mechanisms in Dielectric Films." Advances in Materials Science and Engineering 2014 (2014): 1–18. http://dx.doi.org/10.1155/2014/578168.

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The conduction mechanisms in dielectric films are crucial to the successful applications of dielectric materials. There are two types of conduction mechanisms in dielectric films, that is, electrode-limited conduction mechanism and bulk-limited conduction mechanism. The electrode-limited conduction mechanism depends on the electrical properties at the electrode-dielectric interface. Based on this type of conduction mechanism, the physical properties of the barrier height at the electrode-dielectric interface and the effective mass of the conduction carriers in dielectric films can be extracted. The bulk-limited conduction mechanism depends on the electrical properties of the dielectric itself. According to the analyses of bulk-limited conduction mechanisms, several important physical parameters in the dielectric films can be obtained, including the trap level, the trap spacing, the trap density, the carrier drift mobility, the dielectric relaxation time, and the density of states in the conduction band. In this paper, the analytical methods of conduction mechanisms in dielectric films are discussed in detail.
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3

Audoit, Jérémie, Lydia Laffont, Antoine Lonjon, Eric Dantras, and Colette Lacabanne. "Percolative silver nanoplates/PVDF nanocomposites: Bulk and surface electrical conduction." Polymer 78 (November 2015): 104–10. http://dx.doi.org/10.1016/j.polymer.2015.09.062.

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4

Revesz, A. G., G. A. Brown, and H. L. Hughes. "Bulk Electrical Conduction in the Buried Oxide of SIMOX Structures." Journal of The Electrochemical Society 140, no. 11 (November 1, 1993): 3222–29. http://dx.doi.org/10.1149/1.2221014.

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5

Mukai, Yusuke, and Minyoung Suh. "Enhancing the electrical properties of inkjet-printed silver ink by electrolyte sintering, photonic sintering, and electroless plating." Science of Sintering 53, no. 1 (2021): 119–26. http://dx.doi.org/10.2298/sos2101119m.

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Conductive inkjet printing is an emerging rapid manufacturing technology in the field of smart clothing and wearable electronics. The current challenge in conductive inkjet printing includes upgrading of electrical performance of printed inks to the equivalent level to traditional conductors such as bulk silver and copper, especially for high-performance electronic applications such as flexible antennas and circuits. Post-treatments are commonly employed to enhance the electrical conduction of inkjet-printed tracks. This research discusses the effects of electrolyte sintering, photonic sintering and electroless copper plating on the DC electrical resistance and resistivity of inkjet-printed silver nanoparticles. From experimental results and measurements, it was found that all the post-treatment methods effectively improved the electrical properties of printed silver ink, but in different ways. The lowest resistance of 4.5 ? (in 0.1 mm ? 10 mm) and thickest (4.5 ?m) conductor were achieved by electroless copper plating, whereas the lowest resistivity (7.5?10-8 ??m) and thinnest (1.0 ?m) conductor were obtained by photonic sintering.
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6

Hwang, Cheol Seong. "Bulk- or interface-limited electrical conductions in IrO2/(Ba,Sr)TiO3/IrO2 thin film capacitors." Journal of Materials Research 16, no. 12 (December 2001): 3476–84. http://dx.doi.org/10.1557/jmr.2001.0478.

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The electrical conduction behavior of sputter-grown (Ba,Sr)TiO3 thin films having IrO2 electrodes were studied under the assumption of a fully accumulated film having a negative space charge density of 1 × 1019 cm−3 at 25 °C. The negative space charge decreased the actual field strength in the film and resulted in a decreasing leakage current with increasing film thickness at a given applied field. The current conduction in a very low field, roughly less than 150 KV/cm, showed a linear current density–voltage (J–V) behavior at 25 °C. From that field to about 420 KV/cm, the bulk-limited Poole–Frenkel mechanism controlled the overall conduction property at room temperature. Under high field strength, from 420 KV/cm to 1 MV/cm, the interface-limited thermionic field emission mechanism was dominant. The dielectric constant obtained from Poole–Frenkel fitting was approximately 300 ± 50 at 25 °C, which was in qualitative agreement with the value obtained from low-frequency capacitance measurements. The detailed mechanisms of the linear and nonlinear field-dependent emission conductions were discussed with reference to the direction of band bending, not to the carrier concentration.
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7

Chaudhry, Anurag, and M. Saif Islam. "Examining the Anomalous Electrical Characteristics Observed in InN Nanowires." Journal of Nanoscience and Nanotechnology 8, no. 1 (January 1, 2008): 222–27. http://dx.doi.org/10.1166/jnn.2008.n18.

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Research interest in InN has intensified in recent years because of its unique material properties and promising applications in electronic and photonic devices. Measurements on InN nanowires presented by Chang et al., [J. Electron. Mater. 35, 738 (2006)] showed an anomalous resistance behavior in InN nanowires with diameters less than 90 nm. We examine possible theories presented in literature to explain this intriguing observation. We propose that the presence of a high density electron accumulation layer at the surface of thin InN nanowires is the most probable cause for the uncharacteristic relationship between the total measured resistance and the ratio of length-to-area. High density surface electron accumulation layer, characteristic of InN films and nanowire, promotes a surface conduction path distinct from the bulk conduction. For large diameter nanowires, bulk conduction is likely to be the dominant mechanism while surface conduction is proposed to play a major role for small diameter InN nanowires.
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8

Patel, Satyanarayan, and Harekrishna Yadav. "Electrical conduction properties of the BZT–BST ceramics." Journal of Advanced Dielectrics 10, no. 06 (December 2020): 2050026. http://dx.doi.org/10.1142/s2010135x20500265.

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0.5Ba([Formula: see text][Formula: see text]O3-0.5([Formula: see text][Formula: see text]TiO3 (BZT–BST) has been explored in recent times for potential applications in energy harvesting, electrocaloric and energy storage. To this end, energy harvesting/conversion and storage applications require an understanding of the conduction and loss mechanisms. The conduction mechanism in BZT–BST ceramics is studied using impedance spectroscopy (IS) at 0.1 Hz−3 MHz and 100−600[Formula: see text]C. Impedance study reveals the presence of two types of relaxation processes due to grain and grain boundary contributions. The relaxation time and dc conductivity activation energies are obtained as 1.12/1.3 eV and 1.05/1.2eV for bulk/grain boundary, respectively, and found that oxygen vacancies dominated electrical behavior. The relaxation mechanism follows non-Debye-type behavior. The high resistance of the grain (bulk) in the ferroelectric region does not contribute to the high losses; the losses probably result from the phase transition. Also, BZT–BST ceramics exhibit a negative temperature coefficient of resistance (NTCR) behaviour. From a practical application point of view in the temperature regime of 25–65[Formula: see text]C, the loss’s contribution is low. The significant contributions of loss result from the response of phase-transition in this temperature range (25–65[Formula: see text]C).
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9

Triyono, D., S. N. Fitria, and U. Hanifah. "Dielectric analysis and electrical conduction mechanism of La1−xBixFeO3 ceramics." RSC Advances 10, no. 31 (2020): 18323–38. http://dx.doi.org/10.1039/d0ra02402c.

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10

Sharma, Pankaj, Fei-Xiang Xiang, Ding-Fu Shao, Dawei Zhang, Evgeny Y. Tsymbal, Alex R. Hamilton, and Jan Seidel. "A room-temperature ferroelectric semimetal." Science Advances 5, no. 7 (July 2019): eaax5080. http://dx.doi.org/10.1126/sciadv.aax5080.

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Coexistence of reversible polar distortions and metallicity leading to a ferroelectric metal, first suggested by Anderson and Blount in 1965, has so far remained elusive. Electrically switchable intrinsic electric polarization, together with the direct observation of ferroelectric domains, has not yet been realized in a bulk crystalline metal, although incomplete screening by mobile conduction charges should, in principle, be possible. Here, we provide evidence that native metallicity and ferroelectricity coexist in bulk crystalline van der Waals WTe2by means of electrical transport, nanoscale piezoresponse measurements, and first-principles calculations. We show that, despite being a Weyl semimetal, WTe2has switchable spontaneous polarization and a natural ferroelectric domain structure at room temperature. This new class of materials has tantalizing potential for functional nanoelectronics applications.
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11

Yang, F., L. Li, P. Wu, E. Pradal-Velázquez, H. K. Pearce, and D. C. Sinclair. "Use of the time constant related parameter fmax to calculate the activation energy of bulk conduction in ferroelectrics." Journal of Materials Chemistry C 6, no. 34 (2018): 9258–68. http://dx.doi.org/10.1039/c8tc03011a.

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The use of time constant related parameter fmax to obtain the activation energy for bulk electrical conduction (and any discussion of the possible conduction mechanisms) in ferroelectric materials should be used with caution.
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12

Dijkshoorn, Alexander, Martijn Schouten, Stefano Stramigioli, and Gijs Krijnen. "Modelling of Anisotropic Electrical Conduction in Layered Structures 3D-Printed with Fused Deposition Modelling." Sensors 21, no. 11 (May 26, 2021): 3710. http://dx.doi.org/10.3390/s21113710.

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3D-printing conductive structures have recently been receiving increased attention, especially in the field of 3D-printed sensors. However, the printing processes introduce anisotropic electrical properties due to the infill and bonding conditions. Insights into the electrical conduction that results from the anisotropic electrical properties are currently limited. Therefore, this research focuses on analytically modeling the electrical conduction. The electrical properties are described as an electrical network with bulk and contact properties in and between neighbouring printed track elements or traxels. The model studies both meandering and open-ended traxels through the application of the corresponding boundary conditions. The model equations are solved as an eigenvalue problem, yielding the voltage, current density, and power dissipation density for every position in every traxel. A simplified analytical example and Finite Element Method simulations verify the model, which depict good correspondence. The main errors found are due to the limitations of the model with regards to 2D-conduction in traxels and neglecting the resistance of meandering ends. Three dimensionless numbers are introduced for the verification and analysis: the anisotropy ratio, the aspect ratio, and the number of traxels. Conductive behavior between completely isotropic and completely anisotropic can be modeled, depending on the dimensionless properties. Furthermore, this model can be used to explain the properties of certain 3D-printed sensor structures, like constriction-resistive strain sensors.
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13

Bouaamlat, Hussam, Nasr Hadi, Najat Belghiti, Hayat Sadki, Mohammed Naciri Bennani, Farid Abdi, Taj-dine Lamcharfi, Mohammed Bouachrine, and Mustapha Abarkan. "Dielectric Properties, AC Conductivity, and Electric Modulus Analysis of Bulk Ethylcarbazole-Terphenyl." Advances in Materials Science and Engineering 2020 (January 30, 2020): 1–8. http://dx.doi.org/10.1155/2020/8689150.

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Electrical and dielectric properties for bulk ethylcarbazole-terphenyl (PEcbz-Ter) have been studied over frequency range 1 kHz–2 MHz and temperature range (R.T –120°C). The copolymer PEcbz-Ter was characterised by using X-ray diffraction. The frequency dependence of the dielectric constant (εr′) and dielectric loss (εr″) has been investigated using the complex permittivity. εr′ of the copolymer decreases with increasing frequency and increases with temperature. AC conductivity (σac) data were analysed by the universal power law. The behaviour of σac increases with increasing temperature and frequency. The change of the frequency exponent (s) with temperature was analysed in terms of different conduction mechanisms, and it was found that the correlated barrier-hopping model is the predominant conduction mechanism. The electric modulus was used to analyze the relaxation phenomenon in the material.
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14

Wu, Di, Xiao Li, Lan Luan, Xiaoyu Wu, Wei Li, Maruthi N. Yogeesh, Rudresh Ghosh, et al. "Uncovering edge states and electrical inhomogeneity in MoS2 field-effect transistors." Proceedings of the National Academy of Sciences 113, no. 31 (July 21, 2016): 8583–88. http://dx.doi.org/10.1073/pnas.1605982113.

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The understanding of various types of disorders in atomically thin transition metal dichalcogenides (TMDs), including dangling bonds at the edges, chalcogen deficiencies in the bulk, and charges in the substrate, is of fundamental importance for TMD applications in electronics and photonics. Because of the imperfections, electrons moving on these 2D crystals experience a spatially nonuniform Coulomb environment, whose effect on the charge transport has not been microscopically studied. Here, we report the mesoscopic conductance mapping in monolayer and few-layer MoS2 field-effect transistors by microwave impedance microscopy (MIM). The spatial evolution of the insulator-to-metal transition is clearly resolved. Interestingly, as the transistors are gradually turned on, electrical conduction emerges initially at the edges before appearing in the bulk of MoS2 flakes, which can be explained by our first-principles calculations. The results unambiguously confirm that the contribution of edge states to the channel conductance is significant under the threshold voltage but negligible once the bulk of the TMD device becomes conductive. Strong conductance inhomogeneity, which is associated with the fluctuations of disorder potential in the 2D sheets, is also observed in the MIM images, providing a guideline for future improvement of the device performance.
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15

Neusel, C., H. Jelitto, and G. A. Schneider. "Electrical conduction mechanism in bulk ceramic insulators at high voltages until dielectric breakdown." Journal of Applied Physics 117, no. 15 (April 21, 2015): 154902. http://dx.doi.org/10.1063/1.4917208.

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16

Pietrzak, Tomasz K., Marek Wasiucionek, and Jerzy E. Garbarczyk. "Towards Higher Electric Conductivity and Wider Phase Stability Range via Nanostructured Glass-Ceramics Processing." Nanomaterials 11, no. 5 (May 17, 2021): 1321. http://dx.doi.org/10.3390/nano11051321.

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This review article presents recent studies on nanostructured glass-ceramic materials with substantially improved electrical (ionic or electronic) conductivity or with an extended temperature stability range of highly conducting high-temperature crystalline phases. Such materials were synthesized by the thermal nanocrystallization of selected electrically conducting oxide glasses. Various nanostructured systems have been described, including glass-ceramics based on ion conductive glasses (silver iodate and bismuth oxide ones) and electronic conductive glasses (vanadate-phosphate and olivine-like ones). Most systems under consideration have been studied with the practical aim of using them as electrode or solid electrolyte materials for rechargeable Li-ion, Na-ion, all-solid batteries, or solid oxide fuel cells. It has been shown that the conductivity enhancement of glass-ceramics is closely correlated with their dual microstructure, consisting of nanocrystallites (5–100 nm) confined in the glassy matrix. The disordered interfacial regions in those materials form “easy conduction” paths. It has also been shown that the glassy matrices may be a suitable environment for phases, which in bulk form are stable at high temperatures, and may exist when confined in nanograins embedded in the glassy matrix even at room temperature. Many complementary experimental techniques probing the electrical conductivity, long- and short-range structure, microstructure at the nanometer scale, or thermal transitions have been used to characterize the glass-ceramic systems under consideration. Their results have helped to explain the correlations between the microstructure and the properties of these systems.
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17

Goracci, Guido, and Jorge S. Dolado. "Elucidation of Conduction Mechanism in Graphene Nanoplatelets (GNPs)/Cement Composite Using Dielectric Spectroscopy." Materials 13, no. 2 (January 8, 2020): 275. http://dx.doi.org/10.3390/ma13020275.

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Understanding the mechanisms that govern the conductive properties of multifunctional cement-materials is fundamental for the development of the new applications proposed to enhance the energy efficiency, safety and structural properties of smart buildings and infrastructures. Many fillers have been suggested to increase the electrical conduction in concretes; however, the processes involved are still not entirely known. In the present work, we investigated the effect of graphene nanoplatelets (1 wt% on the electrical properties of cement composites (OPC/GNPs). We found a decrease of the bulk resistivity in the composite associated to the enhancement of the charge transport properties in the sample. Moreover, the study of the dielectric properties suggests that the main contribution to conduction is given by water diffusion through the porous network resulting in ion conductivity. Finally, the results support that the increase of direct current in OPC/GNPs is due to pore refinement induced by graphene nanoplatelets.
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18

Jung, Woo-Hwan. "Dielectric Relaxation and Hopping Conduction in La2NiO4+δ." Journal of Materials 2013 (February 20, 2013): 1–6. http://dx.doi.org/10.1155/2013/169528.

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An ac conductivity as well as dielectric relaxation property of La2NiO4.1 is reported in the temperature range of 77 K–130 K and in the frequency range of 20 Hz–1 MHz. Complex impedance plane plots show that the relaxation (conduction) mechanism in this material is purely a bulk effect arising from the semiconductive grain. The relaxation mechanism has been discussed in the frame of electric modulus spectra. The scaling behavior of the modulus suggests that the relaxation mechanism describes the same mechanism at various temperatures. The logarithmic angular frequency dependence of the loss peak is found to obey the Arrhenius law with the activation energy of ~0.09 eV. The frequency-dependent electrical data are also analyzed in the frame of ac conductivity formalism. The ac conductivity has been found to follow a power-law behavior at a limited temperature and frequency region where Anderson localization plays a significant role in the transport mechanism for La2NiO4.1.
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19

Hamdi, M., A. Oueslati, I. Chaabane, and F. Hlel. "Characterization and Electrical Properties of [C6H9N2]2CuCl4 Compound." ISRN Condensed Matter Physics 2012 (December 20, 2012): 1–8. http://dx.doi.org/10.5402/2012/750497.

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We report measurements of X-ray powder diffraction, vibrational study, the differential scanning calorimetry (DSC), and the electric properties of a made-up [C6H9N2]2CuCl4 sample. The alternative current (ac) conductivity of the compound [C6H9N2]2CuCl4 has been measured in the temperature range 356–398 K and the frequency range 209 Hz–5 MHz. The Cole-Cole (the imaginer part (Z′′) versus real part (Z′) of impedance complex) plots are well fitted to an equivalent circuit model which consists of a parallel combination of a bulk resistance (R) and constant phase elements (CPE). The single semicircle indicates only one primary mechanism for the electrical conduction within [C6H9N2]2CuCl4. The variation of the value of these elements with temperatures confirmed the result detected by DSC and dielectric measurements. Thus the conduction in the material is probably due to a hopping or a small polaron tunneling process.
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20

Kirilenko, K. V. "Dependence of electrical properties of composition material from the structure of the matrix." Кераміка: наука і життя, no. 3(44) (September 22, 2019): 23–29. http://dx.doi.org/10.26909/csl.3.2019.3.

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In the context of rising energy costs and the need to use new energy sources, works aimed at raising the surface temperature of heat radiators with reduced energy consumption are of particular importance, and it is especially important if these processes are also accompanied by the effects of self-stabilization. Bulk materials do not possess these properties. However, materials whose dielectric matrix is also an active element can provide up to 10 - 30% of the thermal energy that will be released in the material, thereby increasing the surface temperature and without increasing energy consumption. Therefore, the study of composite materials with different matrices is relevant. This article the influence of the matrix material on the electrical properties of composite materials was examined. It was established that the microstructure morphology of resistive materials changes significantly depending on the matrix type. In composites based on matrix AlN, for the entire range of concentrations HfC, conducting cluster is formed with a metallic conductivity. For composite systems Al2O3-HfC and Si3N4-HfC thermoactivated hopping conduction between nearest neighboring states observed. Thus, for materials based on Si3N4 matrix at temperatures up to 300°C observed reduction of charge carriers concentration with increasing temperature. The approximation of the temperature dependence of the electrical conductivity was carried out on the basis of the following possible variants of the nature of the electrical conductivity, namely: jump conductivity (nonlocalized states, localized states in the tails of conduction and valence bands, localized states near the Fermi level), tunneling. It can be assumed that the formation of conductive clusters occurred under the influence of two factors: magnetic field and mechanical loading. When using the AlN matrix, the influence of the magnetic field on the structure formation is smallest. This conclusion can be drawn from the fact that the formed conductive clusters have the appearance of a linear chain structure.
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21

Yoon, Seok-Hyun, Clive A. Randall, and Kang-Heon Hur. "Effect of acceptor concentration on the bulk electrical conduction in acceptor (Mg)-doped BaTiO3." Journal of Applied Physics 107, no. 10 (May 15, 2010): 103721. http://dx.doi.org/10.1063/1.3428457.

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22

Ren, Pengrong, Huiqing Fan, and Xin Wang. "Impedance spectroscopy studies of bulk electrical conduction in A-site acceptor (K)-doped BaTiO3." Journal of Materials Science 48, no. 20 (June 19, 2013): 7028–35. http://dx.doi.org/10.1007/s10853-013-7513-4.

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23

Yildiz, A., S. B. Lisesivdin, M. Kasap, S. Ozcelik, E. Ozbay, and N. Balkan. "Investigation of low-temperature electrical conduction mechanisms in highly resistive GaN bulk layers extracted with Simple Parallel Conduction Extraction Method." Applied Physics A 98, no. 3 (December 3, 2009): 557–63. http://dx.doi.org/10.1007/s00339-009-5507-5.

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24

Mitchel, W. C., A. O. Evwaeaye, S. R. Smith, and M. D. Roth. "Hopping conduction in heavily doped bulk n-type SiC." Journal of Electronic Materials 26, no. 3 (March 1997): 113–18. http://dx.doi.org/10.1007/s11664-997-0135-3.

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25

Chung, Hyun-Joong, Jong Han Jeong, Tae Kyung Ahn, Hun Jung Lee, Minkyu Kim, Kyungjin Jun, Jin-Seong Park, Jae Kyeong Jeong, Yeon-Gon Mo, and Hye Dong Kim. "Bulk-Limited Current Conduction in Amorphous InGaZnO Thin Films." Electrochemical and Solid-State Letters 11, no. 3 (2008): H51. http://dx.doi.org/10.1149/1.2826332.

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26

OUESLATI, A., M. HAMDI, I. CHAABANE, F. HLEL, and M. GARGOURI. "IMPEDANCE SPECTROSCOPY STUDY OF BIS(2-AMINO-6-METHYLPYRIDINIUM) TETRACHLORIDOZINCATE." Journal of Advanced Dielectrics 02, no. 04 (October 2012): 1250025. http://dx.doi.org/10.1142/s2010135x12500257.

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The complex impedance of the bis(2-amino-6-methylpyridine) tetrachloridozincate compound (C6H9N2)2ZnCl4 has been investigated in the temperature range 313–403 K and in the frequency range 200 Hz–5 MHz. The impedance plots show semicircle arcs at different temperatures and an electrical equivalent circuit has been proposed to explain the impedance results. The circuits consist of the parallel combination of bulk resistance Rp and constant phase elements (CPE). The bulk resistance of the material decreases with rise in temperature. dc conduction activation energies are estimated from Arrhenius plots. The frequency-dependent conductivity data are fitted in the modified power law: σ ac (ω) = σ dc + A1ωs1 + A2ωs2. Dielectric data were analyzed using complex electrical modulus M* at various temperatures. The modulus plot can be characterized by full width at half height or by β values of Kohlrausch–William–Watts (KWW) function. Activation energy of hopping is almost close to the activation energy of conduction suggesting a hopping transport mechanism.
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27

Deepika and Hukum Singh. "Electrical conduction mechanism in films of Se80−xTe20Bix (0 ≤ x ≤ 12) glassy alloys." Canadian Journal of Physics 97, no. 2 (February 2019): 222–26. http://dx.doi.org/10.1139/cjp-2017-0973.

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This paper reports the study of DC electrical conductivity of films of Se80−xTe20Bix (0 ≤ x ≤ 12) glasses prepared using physical vapor deposition method. The films were structurally characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM results indicate the formation of nanorods within the films. The electrical conductivity of the samples was studied using Keithley electrometer in the temperature range 303–373 K. The results show that conduction in these samples takes place via thermally assisted tunnelling and variable range hopping of charge carriers corresponding to higher and lower temperature ranges, respectively. Further, it was found that the conductivity increases with increase in Bi concentration in Se–Te system. This has been explained on the basis of chemically ordered network model. It was also found that nanorod formation improves the electrical conductivity of Se–Te–Bi system compared to bulk Se–Te–Bi system.
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28

SUBRAMANYAM, GURU, CARRIE M. BARTSCH, JAMES G. GROTE, RAJESH R. NAIK, LAWRENCE L. BROTT, MORLEY STONE, and ANGELA CAMPBELL. "EFFECT OF EXTERNAL ELECTRICAL STIMULI ON DNA-BASED BIOPOLYMERS." Nano 04, no. 02 (April 2009): 69–76. http://dx.doi.org/10.1142/s179329200900154x.

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Biopolymers, such as deoxyribonucleic acid-hexadecyltrimethyl ammonium chloride (DNA-CTMA) and bovine serum albumin-polyvinyl alcohol (BSA-PVA), were studied using a novel capacitive test structure. A variety of external electrical stimuli were applied, including a low frequency alternating current signal and a rf/microwave frequency signal combined with a DC bias. The dynamic responses of the DNA-based biopolymer to the external stimuli are presented in this paper. The electrical transport measurements support the space-charge-limited conduction and the low frequency capacitance–voltage (CV) measurements showed large depletion layer capacitance at the Au –biopolymer interface, at 20 Hz, and the capacitance approaching bulk values at 1 MHz. Electric force microscopy (EFM) was utilized for visualization of charge dynamics and to examine the effect of DC bias combined with an AC signal. Ionic charges in the DNA-CTMA system seem to be responsible for the dynamic response to the various external electrical stimuli.
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29

McCluskey, Matthew D., Caleb D. Corolewski, Violet M. Poole, and Marianne C. Tarun. "Persistent Photoconductivity in Bulk Strontium Titanate." MRS Proceedings 1675 (2014): 87–91. http://dx.doi.org/10.1557/opl.2014.800.

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ABSTRACTStrontium titanate (SrTiO3) has novel properties, including a large temperature-dependent dielectric constant, and can be doped to make it metallic or even superconducting. The origin of conductivity observed at the SrTiO3/LaAlO3 interface is a topic of intense debate. In the present work, bulk single crystal SrTiO3 samples were heated at 1200°C, with the goal of producing cation vacancies. These thermally treated samples exhibited persistent photoconductivity (PPC) at room temperature. Upon exposure to sub-band-gap light (>2.9 eV), the free-electron density increases by over two orders of magnitude. This enhanced conductivity persists in the dark, at room temperature, for several days with essentially no decay. Light excites an electron from the vacancy to the conduction band, where it remains, due to a large recapture barrier. These observations highlight the importance of defects in determining the electrical properties of oxides and may point toward novel applications.
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30

Du, Yong, Jia Li, Jiayue Xu, and Per Eklund. "Thermoelectric Properties of Reduced Graphene Oxide/Bi2Te3 Nanocomposites." Energies 12, no. 12 (June 24, 2019): 2430. http://dx.doi.org/10.3390/en12122430.

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Reduced graphene oxide (rGO)/Bi2Te3 nanocomposite powders with different contents of rGO have been synthesized by a one-step in-situ reductive method. Then, rGO/Bi2Te3 nanocomposite bulk materials were fabricated by a hot-pressing process. The effect of rGO contents on the composition, microstructure, TE properties, and carrier transportation of the nanocomposite bulk materials has been investigated. All the composite bulk materials show negative Seebeck coefficient, indicating n-type conduction. The electrical conductivity for all the rGO/Bi2Te3 nanocomposite bulk materials decreased with increasing measurement temperature from 25 °C to 300 °C, while the absolute value of Seebeck coefficient first increased and then decreased. As a result, the power factor of the bulk materials first increased and then decreased, and a power factor of 1340 μWm−1K−2 was achieved for the nanocomposite bulk materials with 0.25 wt% rGO at 150 °C.
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31

Dalapati, Goutam Kumar, Avishek Kumar, Andrew See Weng Wong, Manippady Krishna Kumar, Ching Kean Chia, Ghim Wei Ho, and Dong Zhi Chi. "Sputter-Deposited ZrO2 Gate Dielectric on High Mobility Epitaxial-GaAs/Ge Channel Material for Advanced CMOS Applications." Key Engineering Materials 443 (June 2010): 504–9. http://dx.doi.org/10.4028/www.scientific.net/kem.443.504.

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Sputtered-deposited ZrO2 gate dielectric on epitaxial-GaAs/Ge substrates have been studied for complementary-metal-oxide-semiconductor (CMOS) applications. The epitaxial-GaAs (epi-GaAs) on Ge susbstrates with AlGaAs interlayer was grown by metal-organic chemical vapor deposition at 650oC. High resolution transmission electron microscopy ((HRTEM) shows that the epilayers are free from arsenic anti-phase defects (APD). From secondary ion mass spectrometry, it was confirmed that the Ge diffusion is completely blocked by the AlGaAs layer and no Ge atoms are able to penetrate into the GaAs layer. The macroscopic surface roughness of epitaxial GaAs is ~5.3nm, whereas over 200x200nm is 0.4 nm, which is comparable with bulk GaAs. Althogh, the epi-GaAs has nano-scale surface features; the conduction-AFM shows electrically homogeneous surface. The electrical and interfacial properties of MOS capacitors with sputtered deposited ZrO2 dielectric on epitaxial-GaAs/Ge and bulk GaAs substrates were investigated. The frequency dispersion and hysteresis voltage for directly deposited ZrO2 on epi-GaAs is higher compared with bulk p-GaAs, however, it is comparable with bulk n-GaAs. The interfacial and electrical properties of ZrO2 on epi-GaAs have shown to exhibit better electrical characteristics after post deposition annealing (PDA) at 400oC. The apparent doping profile of the epitaxial layer is unchanged with PDA temperatures, which suggest the less cross-diffusion of Ge, Ga, and As during device fabrication. The degradation of the gate oxide quality and interface properties are mainly due to the high surface roughness of epitaxial layer and also presence of elemental out diffusion of Ga and As.
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32

Paun, Maria-Alexandra. "Main Parameters Characterization of Bulk CMOS Cross-Like Hall Structures." Advances in Materials Science and Engineering 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/6279162.

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A detailed analysis of the cross-like Hall cells integrated in regular bulk CMOS technological process is performed. To this purpose their main parameters have been evaluated. A three-dimensional physical model was employed in order to evaluate the structures. On this occasion, numerical information on the input resistance, Hall voltage, conduction current, and electrical potential distribution has been obtained. Experimental results for the absolute sensitivity, offset, and offset temperature drift have also been provided. A quadratic behavior of the residual offset with the temperature was obtained and the temperature points leading to the minimum offset for the three Hall cells were identified.
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33

Trippe, Simone C., Joana Catarina Madaleno, and Luiz Pereira. "Electrical Properties of Fluorine Doped Diamond Like Carbon." Materials Science Forum 514-516 (May 2006): 53–57. http://dx.doi.org/10.4028/www.scientific.net/msf.514-516.53.

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In this work fluorinated Diamond Like Carbon (DLC) films have been grown with different CF4 concentrations and have been studied by electrical DC measurements in a temperature range from 30 to 300 K. It was found that the samples grown with lower CF4 concentration show a small rectification, with a potential barrier lower than 0.3 V. The bulk conduction shows a trapcontrolled Space Charge Limited Current (SCLC), with characteristic trap energy between 0.08 and 0.13 eV, confirmed by the differential conductivity analysis. The activation energy (ranging from 50 to 140 meV) is also dependent on the sample fluorine concentration, decreasing with the fluorine concentration increase.
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34

Xiang, Z., Y. Kasahara, T. Asaba, B. Lawson, C. Tinsman, Lu Chen, K. Sugimoto, et al. "Quantum oscillations of electrical resistivity in an insulator." Science 362, no. 6410 (August 30, 2018): 65–69. http://dx.doi.org/10.1126/science.aap9607.

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In metals, orbital motions of conduction electrons on the Fermi surface are quantized in magnetic fields, which is manifested by quantum oscillations in electrical resistivity. This Landau quantization is generally absent in insulators. Here, we report a notable exception in an insulator—ytterbium dodecaboride (YbB12). The resistivity of YbB12, which is of a much larger magnitude than the resistivity in metals, exhibits distinct quantum oscillations. These unconventional oscillations arise from the insulating bulk, even though the temperature dependence of the oscillation amplitude follows the conventional Fermi liquid theory of metals with a large effective mass. Quantum oscillations in the magnetic torque are also observed, albeit with a lighter effective mass.
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35

HARI, PARAMESWAR, MICHAL BYRCZEK, DALE TEETERS, and PRAVIN UTEKAR. "INVESTIGATIONS ON THE ELECTRICAL PROPERTIES OF ZnO NANORODS AND COMPOSITES FOR PHOTOVOLTAIC AND ELECTROCHEMICAL APPLICATIONS." International Journal of Nanoscience 10, no. 01n02 (February 2011): 81–85. http://dx.doi.org/10.1142/s0219581x1100748x.

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ZnO nanorods grown by hydrothermal technique on glass, Zinc, and Indium tin oxide (ITO) substrates exhibit both open and closed hexagonal structures. On the nanoscale, closed ZnO nanostructures exhibit two types of ion conduction regions as revealed by AC-impedance spectra collected through the tip of an atomic force microscope (AFM). One region has higher impedance values (apparent values of approximately 107 ohms) with two semicircles. Two semicircles are indicative of a ZnO structure composed of bulk and grain boundary conduction. Other regions were found to have impedance values that were two orders of magnitude lower (apparent values of 105 ohms). This indicates that these ZnO films have two conduction pathways. The polyethylene oxide ( PEO )– ZnO nanorod composite was made by spin-coating the ZnO rods growing from the ITO substrate with PEO. In the PEO – ZnO composite film, only the AC impedance values of 105 ohms were observed. This is higher than PEO electrolyte without ZnO nanorods. Since regions of higher impedance were not seen in the PEO – ZnO nanorod composites, the polymer electrolyte either dominated the conduction of the system or suppressed the first pathway of higher impedance in the ZnO rods.
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36

Yue, Chenxi, Shuye Jiang, Hao Zhu, Lin Chen, Qingqing Sun, and David Zhang. "Device Applications of Synthetic Topological Insulator Nanostructures." Electronics 7, no. 10 (October 1, 2018): 225. http://dx.doi.org/10.3390/electronics7100225.

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This review briefly describes the development of synthetic topological insulator materials in the application of advanced electronic devices. As a new class of quantum matter, topological insulators with insulating bulk and conducting surface states have attracted attention in more and more research fields other than condensed matter physics due to their intrinsic physical properties, which provides an excellent basis for novel nanoelectronic, optoelectronic, and spintronic device applications. In comparison to the mechanically exfoliated samples, the newly emerging topological insulator nanostructures prepared with various synthetical approaches are more intriguing because the conduction contribution of the surface states can be significantly enhanced due to the larger surface-to-volume ratio, better manifesting the unique properties of the gapless surface states. So far, these synthetic topological insulator nanostructures have been implemented in different electrically accessible device platforms via electrical, magnetic and optical characterizations for material investigations and device applications, which will be introduced in this review.
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37

SCHLETTWEIN, D., J. P. MEYER, and N. I. JAEGER. "Intermolecular Interactions and Electrical Properties in Thin Films of Tetrapyridotetraazaporphyrinatozinc(II)." Journal of Porphyrins and Phthalocyanines 03, no. 07 (October 1999): 611–19. http://dx.doi.org/10.1002/(sici)1099-1409(199908/10)3:6/7<611::aid-jpp184>3.0.co;2-c.

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Tetrapyridotetraazaporphyrinatozinc ( TPyTAPZn ) can be looked at as a substituted phthalocyanine. Thin films of TPyTAPZn were prepared on quartz glass by physical vapour deposition under high-vacuum conditions. During the deposition, island growth was observed by a characteristic change in the electrical conduction, indicating an increasing number of conduction pathways along the film. Deposition conditions could be optimized to yield an ordered rather than amorphous growth as detected by a characteristic absorption band in the visible range, strongly red-shifted from the absorption of the monomeric molecule in solution. A negative Seebeck coefficient confirmed n-type conduction for TPyTAPZn . In temperature-dependent measurements of the electrical conductivity and thermopower across the samples an activation energy of 0.31 eV was established for the conductivity and of 0.04 eV for charge carrier generation. From this difference it is concluded that a thermally activated charge carrier transport mechanism (hopping) rather than delocalized conduction (band model) is dominant in TPyTAPZn . Photoconduction turned out to be rather small in these samples, although light was absorbed quite efficiently. The time dependence of photoconduction indicated a significant trap density. Interaction with ammonia or triethylamine in the gas phase led to an increase in the conductivity; oxygen or water led to a decrease. The time dependence of these interactions indicated that triethylamine and water were only reacting with the surface region, whereas NH 3 and O 2 were also diffusing into the bulk of the films.
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38

Song, Jianmin, Jie Gao, Suwei Zhang, Laihui Luo, Xiuhong Dai, Lei Zhao, and Baoting Liu. "Structure and Electrical Properties of Na0.5Bi0.5TiO3 Epitaxial Films with (110) Orientation." Crystals 9, no. 11 (October 25, 2019): 558. http://dx.doi.org/10.3390/cryst9110558.

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Pt/Na0.5Bi0.5TiO3/La0.5Sr0.5CoO3 (Pt/NBT/LSCO) ferroelectric capacitors were fabricated on (110) SrTiO3 substrate. Both NBT and LSCO films were epitaxially grown on the (110) SrTiO3 substrate. It was found that the leakage current density of the Pt/NBT/LSCO capacitor is favorable to ohmic conduction behavior when the applied electric fields are lower than 60 kV/cm, and bulk-limited space charge-limited conduction takes place when the applied electric fields are higher than 60 kV/cm. The Pt/NBT/LSCO capacitor possesses good fatigue resistance and retention, as well as ferroelectric properties with Pr = 35 μC/cm2. The ferroelectric properties of the Pt/NBT/LSCO capacitor can be modulated by ultraviolet light. The effective polarization, ΔP, was reduced and the maximum polarization Pmax was increased for the Pt/NBT/LSCO capacitor when under ultraviolet light, which can be attributed to the increased leakage current density and non-reversible polarization P^ caused by the photo-generated carriers.
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39

Valenzuela, Edgar, S. A. Gamboa, P. J. Sebastian, J. Moreira, J. Pantoja, G. Ibañez, A. Reyes, B. Campillo, and S. Serna. "Proton Charge Transport in Nafion Nanochannels." Journal of Nano Research 5 (February 2009): 31–36. http://dx.doi.org/10.4028/www.scientific.net/jnanor.5.31.

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The Nafion perfluorinated membranes are one of the best electrolytes used in the Proton Exchange Membrane Fuel Cell (PEMFC). Some methods have been used to study the electrical properties of Nafion; nevertheless, there are some aspects of the conduction process that are not well understood, such as the contribution of the bulk and the interfacial phenomena to the total proton conduction process. In this work the Electrochemical Impedance Spectroscopy (EIS) was employed in a four electrode system to study the protonic charge transport under conditions that simulate the operation of the PEMFC. Two Nafion membranes were evaluated to determine the relation of the activation procedure with the resistance to the protonic charge transference. The results are not only consistent with other measurements but also allow to separate the protonic charge transference process in two stages. Each stage was studied and their electrical parameters were calculated using Electrical Equivalent Circuits.
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40

Shin, Woosuck, Akihiro Tsuruta, Toshio Itoh, Takafumi Akamatsu, and Ichiro Terasaki. "High Temperature Electrical Properties of Co-Substituted La4BaCu5O13+δ Thin Films Fabricated by Sputtering Method." Materials 14, no. 10 (May 20, 2021): 2685. http://dx.doi.org/10.3390/ma14102685.

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The high-temperature conductivity of the perovskite oxides of a La4BaCu5O13+δ (LBCO) thin film prepared by RF sputtering deposition and thermal annealing has been studied. While the bulk LBCO compound was metallic, the LBCO film deposited on a Si substrate by sputtering and a post annealing process showed semiconductor-like conduction, which is considered to be due to the defects and poor grain connectivity in the LBCO film on the Si substrate. The LBCO film deposited on a SrTiO3 substrate was of high film quality and showed metallic conduction. When the cation site Cu was substituted by Co, the electrical conductivity of the LBCO film increased further and its temperature dependence became smaller. The transport properties of LBCO films are investigated to understand its carrier generation mechanism.
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41

Jia, Jianliang, Renjie Zhou, Zhaojun Liu, Xuehui Han, and Yuan Gao. "Organic matter-driven electrical resistivity of immature lacustrine oil-prone shales." GEOPHYSICS 86, no. 4 (June 1, 2021): MR165—MR178. http://dx.doi.org/10.1190/geo2020-0238.1.

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Organic matter (OM) and minerals are major particle components in lacustrine organic-rich shales. Their association and distribution control the development of the primary pore space. The response of OM-driven conduction by modifying the pore-space volume and structure in organic-rich shales of the virgin zone is still unclear. Based on a detailed study of geochemical, mineralogical, and geophysical properties from immature lacustrine oil-prone shales of the Songliao Basin (Northeast China), we have observed a novel continuous variation of electrical resistivity driven by large ranges of total-organic-carbon (TOC) content (0.64–24.51 wt%). The reduced resistivity at low TOC content ([Formula: see text]) and then enhanced resistivity at high TOC content ([Formula: see text]) are present in our immature shales. These variations in electrical resistivity are confirmed by fluid (S1) and solid organic compounds (S2). Furthermore, clay and detrital minerals in shales contribute to the variation of electrical resistivity as well as OMs at low and high TOC content. The electrical resistivity of shales is closely related to the pore-space volume and structure for the electrical flow pathway. Two resistivity trends are highlighted by pore parameters such as the pore volume, throat/pore ratio, pore diameter, and bulk density. Although reduced amounts and the arrangement of large pores for low TOC content cannot decrease the conduction, the enhanced additional clay conduction and low OM concentration reduce the resistivity of shales. Moreover, increased amounts of nonconductive fluid and solid organic compounds and the effect of OM filling on pore space during high TOC content enhance the resistivity of shales. Thus, modified minerals and pore space driven by various OMs affect the electrical resistivity of immature shales. These results improve the understanding of OM-driven conduction in shales and contribute to the evaluation of source rocks using a well-log method.
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42

Улашкевич, Ю. В., В. В. Каминский, С. М. Соловьев, and Н. В. Шаренкова. "Спектры пленок SmS в дальней и средней ИК областях." Физика и техника полупроводников 53, no. 11 (2019): 1544. http://dx.doi.org/10.21883/ftp.2019.11.48452.9163.

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AbstractThe basic features of the band structure observed in bulk samples are retained in polycrystalline SmS thin films. Specifically, the bottom of the conduction band is formed from s -type states and there exist donor impurity levels in the band gap, at an energy of 0.04–0.065 eV below the bottom of the conduction band.
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43

Kogut, Iurii, Carsten Steiner, Hendrik Wulfmeier, Alexander Wollbrink, Gunter Hagen, Ralf Moos, and Holger Fritze. "Comparison of the electrical conductivity of bulk and film Ce1–xZrxO2–δ in oxygen-depleted atmospheres at high temperatures." Journal of Materials Science 56, no. 30 (August 17, 2021): 17191–204. http://dx.doi.org/10.1007/s10853-021-06348-5.

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AbstractFeaturing high levels of achievable oxygen non-stoichiometry δ, Ce1−xZrxO2−δ solid solutions (CZO) are crucial for application as oxygen storage materials in, for example, automotive three-way catalytic converters (TWC). The use of CZO in form of films combined with simple manufacturing methods is beneficial in view of device miniaturization and reducing of TWC manufacturing costs. In this study, a comparative microstructural and electrochemical characterization of film and conventional bulk CZO is performed using X-ray diffractometry, scanning electron microscopy, and impedance spectroscopy. The films were composed of grains with dimensions of 100 nm or less, and the bulk samples had about 1 µm large grains. The electrical behavior of nanostructured films and coarse-grained bulk CZO (x > 0) was qualitatively similar at high temperatures and under reducing atmospheres. This is explained by dominating effect of Zr addition, which masks microstructural effects on electrical conductivity, enhances the reducibility, and favors strongly electronic conductivity of CZO at temperatures even 200 K lower than those for pure ceria. The nanostructured CeO2 films had much higher electrical conductivity with different trends in dependence on temperature and reducing atmospheres than their bulk counterparts. For the latter, the conductivity was dominantly electronic, and microstructural effects were significant at T < 700 °C. Nanostructural peculiarities of CeO2 films are assumed to induce their more pronounced ionic conduction at medium oxygen partial pressures and relatively low temperatures. The defect interactions in bulk and film CZO under reducing conditions are discussed in the framework of conventional defect models for ceria.
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44

DEVI, CH SAMEERA, M. B. SURESH, G. S. KUMAR, and G. PRASAD. "SYNTHESIS, CHARACTERIZATION AND ELECTRICAL PROPERTIES OF Nd/Zr CO-DOPED NANO BaTiO3 CERAMICS." Journal of Advanced Dielectrics 02, no. 01 (January 2012): 1250001. http://dx.doi.org/10.1142/s2010135x12500014.

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Ceramic samples of composition Ba 1-3x Nd 2x Ti 1-y Zr y O 3 (x = 0.025;y = 0,0.025 and 0.05) were synthesized by modified sol–gel technique. Phase confirmation, surface morphology and electrical properties of the samples were studied using XRD, FESEM, impedance spectroscopy and DC conductivity. Impedance, AC and DC conductivities of the samples were recorded in the temperature range room temperature (RT) –500°C. From impedance data, various parameters like bulk resistance (R b ), bulk capacitance (C b ), grain resistance (R g ), grain boundary resistance (R gb ), grain capacitance (C g ) and grain boundary capacitance (C gb ) were determined. These parameters were found to be function of both temperature and frequency. Grain and grain boundary relaxation times (τg,τgb) were also evaluated as a function of temperature. From AC and DC conductivity plots activation energies for conduction were obtained. Results obtained lead to improved understanding of conductivity and charge transportation kinetics in the present system of samples.
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45

Roy, Ansu Kumar, Kamal Prasad, and Ashutosh Prasad. "Electrical Conduction in (Na0.5Bi0.5)1−xBaxTiO3 (0≤x≤1) Ceramic by Complex Impedance/Modulus Spectroscopy." ISRN Ceramics 2013 (March 21, 2013): 1–12. http://dx.doi.org/10.1155/2013/369670.

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The present work describes the piezoelectric, impedance, and conductivity studies of (Na0.5Bi0.5)1−xBaxTiO3; (1-x)BNT-xBT (0≤x≤1) ceramics. The ceramics were prepared by conventional ceramic fabrication technique. X-ray diffraction data confirmed the formation of a pure compound in all the compositions. Williamson-Hall plot yielded the apparent crystallite sizes ~26–52 nm, and SEM micrograph showed grain sizes ranging between 1.8–3.5 μm for the material samples. Values of longitudinal piezoelectric charge coefficients of the samples poled under a dc electric field of about 2.5 kV/mm at 80°C/15 min indicated that their piezoelectric properties near the MPB are rather sensitive to the phase composition and reach preferred values at x=0.08, where the relative content of the tetragonal phase is significantly higher than that of the monoclinic phase. Complex impedance/modulus spectroscopic analyses indicated the presence of grain-boundary effect along with the bulk contribution and also confirmed the presence of non-Debye type of multiple relaxations in the materials. The temperature dependent electrical conductivity data suggest the negative temperature coefficient of resistance behaviour. The activation energy studies allow insight into the nature of the conduction mechanisms occurring in the materials system which are explained on the basis of hopping model of charge carriers.
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46

Reddy, Y. S. "Electrical transport and magnetoresistance of double layered CMR manganites R1.2Sr1.8Mn2O7(R = La, Pr, Sm)." Materials Science-Poland 35, no. 2 (July 26, 2017): 440–46. http://dx.doi.org/10.1515/msp-2017-0048.

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Abstract Polycrystalline bulk samples of double layered (DL) colossal magnetoresistive (CMR) manganites R1.2Sr1.8Mn2O7 (R = La, Pr, Sm) were prepared by sol-gel method to study the effect of size of lanthanide ion on their magnetotransport properties. The electrical resistivity of the samples was investigated in the temperature range of 70 K to 300 K at different magnetic fields. The samples LSMO and PSMO show insulator-to-metal transition (IMT) behavior, while SSMO sample exhibits insulating behavior in the entire temperature range with a very large value of resistivity. The insulator-to-metal transition temperature (TIM) decreases from 123 K (LSMO) to 90 K (PSMO) and disappears in SSMO sample. To explain the electrical transport above TIM, the temperature dependent resistivity data (T > TIM) of all the samples were fitted to the equations of different conduction models. The results indicate that the conduction at T > TIM is due to Mott variable range hopping (VRH) mechanism in the LSMO and PSMO samples, while Efros-Shkloskii (ES) type of VRH model dominates the conduction process in the SSMO sample. All the three samples show increasing magnetoresistance (MR) even below TIM and the maximum MR is shown by LSMO (39 % at 75 K, 3 T).
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47

Megdiche, Makram, and Mohamed Gargouri. "AC Conductivity and Mechanism of Conduction Study of ?-Sr2P2O7 Using Impedance Spectroscopy." JOURNAL OF ADVANCES IN PHYSICS 4, no. 1 (March 22, 2014): 433–48. http://dx.doi.org/10.24297/jap.v4i1.2054.

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The ceramic sample Sr2P2O7 was prepared by a solid-state reaction technique at high temperature. Electrical properties and modulus analysis were studied using complex impedance spectroscopy in the frequency range 200 Hz–5 MHz and temperature range 602-714 K. The difference of the value of activation energy for the bulk obtained from analysis of equivalent circuit (0.81 eV) and modulus relaxation (0.69 eV) confirms that the transport is not due from a simple hopping mechanism. The average of the power law exponent s is reasonably interpreted by the overlapping large polaron tunneling (OLPT) model. The mechanism of conduction is probably due from the displacements of the Sr2+ ion in the tunnel-type cavities along the b axis.
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48

Sampayan, K. C. "16 kV, 75 kHz, 50% Duty Cycle, SiC Photonic Based Bulk Conduction Power Switch Development." Materials Science Forum 897 (May 2017): 583–86. http://dx.doi.org/10.4028/www.scientific.net/msf.897.583.

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A transconductance-like behavior similar to that of junction semiconductor devices is observed in photonically excited wide bandgap (WBG) semi-insulating material without a junction. This property offers the possibility of power electronic devices capable of virtually unlimited voltage and current carrying capability due to intrinsic electrical isolation of the controlling voltage from the switched high voltage. A proof of concept experiment demonstrated the transconductance-like property in burst mode switching to >16 kV, 50% duty cycle, and 75 kHz. Our eventual goal is to combine the light source, optics and the WBG material to form a compact module that is functionally equivalent to junction power electronic devices. In this paper, we present the background, our generalized approach for implementing photoconductive switching for potential applications to high repetition rate (>50 kHz), high voltage (>15 kV) power switching, our associated material measurements, and our path forward to multi-10s of ampere devices.
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49

Kumar, Arvind, R. Prasad, A. K. Debnath, Ajay Singh, S. Samanta, D. K. Aswal, and S. K. Gupta. "Growth and Electrical Transport Properties of Organic Semiconductor Thin Films." Solid State Phenomena 209 (November 2013): 1–5. http://dx.doi.org/10.4028/www.scientific.net/ssp.209.1.

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Hexadecafluorophthalocyanine (F16CuPc) and Cobalt phthalocyanone (CoPc) thin films of different thickness (20-200nm) have been grown by Molecular Beam Epitaxy (MBE) using different deposition rate (0.2 – 1.0 Å/s). For nanowire type growth lower deposition rate and for films of smooth surface higher deposition rate are found suitable. Charge transport (J~V) of CoPc and F16CuPc films is governed by bulk-limited processes with a bias dependent crossover from Ohmic to trap-free space-charge-limited conduction. The mobility (μ) values at 300 K were found 4.5 and 5.5 cm2 V−1 s−1 for CoPc and F16CuPc films respectively. Mechanism of reverse rectification behavior of an organic heterojunction comprising of CoPc and F16CuPc is explained by Kelvin Probe measurement.
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50

Anselmi-Tamburini, U., J. E. Garay, Z. A. Munir, A. Tacca, F. Maglia, G. Chiodelli, and G. Spinolo. "Spark plasma sintering and characterization of bulk nanostructured fully stabilized zirconia: Part II. Characterization studies." Journal of Materials Research 19, no. 11 (November 1, 2004): 3263–69. http://dx.doi.org/10.1557/jmr.2004.0424.

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Dense fully stabilized cubic zirconia, sintered by the spark plasma sintering (SPS) method, was characterized through hardness, fracture toughness, and electrical impedance measurements. The effect of sintering temperature on hardness and fracture toughness was evaluated. Samples sintered at 1200 °C for 5 min, which had crystallite size of <100 nm, exhibited the highest hardness. Impedance measurements showed an increase in bulk contribution relative to grain boundaries as sintering temperature is increased. Calculation of the activation energy for conduction gave a value, 1.13 eV, in agreement with previously published results.
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