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Journal articles on the topic 'Charge carriers dynamic'

Author: Grafiati
Published: 9 March 2023
Last updated: 10 March 2023

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1

Katayama, Kenji, Tatsuya Chugenji, and Kei Kawaguchi. "Charge Carrier Trapping during Diffusion Generally Observed for Particulate Photocatalytic Films." Energies 14, no. 21 (October 26, 2021): 7011. http://dx.doi.org/10.3390/en14217011.

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Photo-excited charge carriers play a vital role in photocatalysts and photovoltaics, and their dynamic processes must be understood to improve their efficiencies by controlling them. The photo-excited charge carriers in photocatalytic materials are usually trapped to the defect states in the picosecond time range and are subject to recombination to the nanosecond to microsecond order. When photo-excited charge carrier dynamics are observed via refractive index changes, especially in particulate photocatalytic materials, another response between the trapping and recombination phases is often observed. This response has always provided the gradual increase of the refractive index changes in the nanosecond order, and we propose that the shallowly trapped charge carriers could still diffuse and be trapped to other states during this process. We examined various photocatalytic materials such as TiO2, SrTiO3, hematite, BiVO4, and methylammonium lead iodide for similar rising responses. Based on our assumption of surface trapping with diffusion, the responses were fit with the theoretical model with sufficient accuracy. We propose that these slow charge trapping processes must be included to fully understand the charge carrier dynamics of particulate photocatalytic materials.
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2

Du, Luchao, Xiaoping Shi, Menghan Duan, and Ying Shi. "Pressure-Induced Tunable Charge Carrier Dynamics in Mn-Doped CsPbBr3 Perovskite." Materials 15, no. 19 (October 8, 2022): 6984. http://dx.doi.org/10.3390/ma15196984.

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All-inorganic perovskite materials (CsPbX3) have attracted increasing attention due to their excellent photoelectric properties and stable physical and chemical properties. The dynamics of charge carriers affect the photoelectric conversion efficiencies of perovskite materials. Regulating carrier dynamics by changing pressure is interesting with respect to revealing the key microphysical processes involved. Here, ultrafast spectroscopy combined with high-pressure diamond anvil cell technology was used to study the generation and transfer of photoinduced carriers of a Mn-doped inorganic perovskite CsPbBr3 material under pressure. Three components were obtained and assigned to thermal carrier relaxation, optical phonon–acoustic phonon scattering and Auger recombination. The time constants of the three components changed under the applied pressures. Our experimental results show that pressure can affect the crystal structure of Mn-doped CsPbBr3 to regulate carrier dynamics. The use of metal doping not only reduces the content of toxic substances but also improves the photoelectric properties of perovskite materials. We hope that our study can provide dynamic experimental support for the exploration of new photoelectric materials.
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Moore, Kalani, Lynette Keeney, Clive Downing, Michele Conroy, and Ursel Bangert. "Charge Carriers in Dynamic Ferroelectric Domain Walls." Microscopy and Microanalysis 26, S2 (July 30, 2020): 1140–41. http://dx.doi.org/10.1017/s1431927620017079.

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4

Du, Sichao, Juxin Yin, Hao Xie, Yunlei Sun, Tao Fang, Yu Wang, Jing Li, et al. "Auger scattering dynamic of photo-excited hot carriers in nano-graphite film." Applied Physics Letters 121, no. 18 (October 31, 2022): 181104. http://dx.doi.org/10.1063/5.0116720.

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Charge carrier scattering channels in graphite bridging its valence and conduction band offer an efficient Auger recombination dynamic to promote low energy charge carriers to higher energy states. It is of importance to answer the question whether a large number of charge carriers can be promoted to higher energy states to enhance the quantum efficiency of photodetectors. Here, we present an experimental demonstration of an effective Auger recombination process in the photo-excited nano-graphite film. The time-resolved hot carrier thermalization was analyzed based on the energy dissipation via the Auger scattering channels. We split the Auger recombination occurrence centered at 0.40 eV energy state into scattering and recombination parts, for characterizing the scattering rate in the conduction band and the recombination rate toward the valence band. The scattering time with respect to the energy state was extracted as 8 ps · eV−1, while the recombination time with respect to the energy state was extracted as 24 ps · eV−1. Our study indicates a 300 fs delay between the hot carrier recombination and generation, leading to a 105 ps−1 · cm−3 Auger scattering efficiency. The observed duration for the Auger recombination to generate hot carriers is prolonged for 1 ps, due to the hot carriers energy relaxation bottleneck with optical-phonons in the nano-graphite. The presented analytic expression gives valuable insights into the Auger recombination dynamic to estimate its most efficient energy regime for mid-infrared photodetection.
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5

KUZEMSKY, A. L. "BOUND AND SCATTERING STATES OF ITINERANT CHARGE CARRIERS IN COMPLEX MAGNETIC MATERIALS." International Journal of Modern Physics B 18, no. 23n24 (October 10, 2004): 3227–66. http://dx.doi.org/10.1142/s0217979204026391.

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The concept of magnetic polaron is analyzed and developed to elucidate the nature of itinerant charge carrier states in magnetic semiconductors and similar complex magnetic materials. By contrasting the scattering and bound states of carriers within the s–d exchange model, the nature of bound states at finite temperatures is clarified. The free magnetic polaron at certain conditions is realized as a bound state of the carrier (electron or hole) with the spin wave. Quite generally, a self-consistent theory of a magnetic polaron is formulated within a nonperturbative many-body approach, the Irreducible Green Functions (IGF) method which is used to describe the quasiparticle many-body dynamics at finite temperatures. Within the above many-body approach we elaborate a self-consistent picture of dynamic behavior of two interacting subsystems, the localized spins and the itinerant charge carriers. In particular, we show that the relevant generalized mean fields emerges naturally within our formalism. At the same time, the correct separation of elastic scattering corrections permits one to consider the damping effects (inelastic scattering corrections) in the unified and coherent fashion. The damping of magnetic polaron state, which is quite different from the damping of the scattering states, finds a natural interpretation within the present self-consistent scheme.
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6

Frolov, I. V., O. A. Radaev, and V. A. Sergeev. "Investigation of the dynamic parameters of electroluminescence in different parts of the spectrum in local regions of the light-emitting heterostructure." Journal of Physics: Conference Series 2086, no. 1 (December 1, 2021): 012083. http://dx.doi.org/10.1088/1742-6596/2086/1/012083.

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Abstract A method for measuring the distribution of the differential charge carriers lifetime over energy levels in the local regions of a light-emitting heterostructure is presented. The method has been tested on commercial green InGaN-based LEDs. It has been determined that with an increase in the energy level (with decreasing wavelength), the charge carriers lifetime decreases. It is shown that the relative inhomogeneity of the distribution of the charge carriers lifetimes in local regions of the die in the long-wavelength part of the electroluminescence spectrum is higher than in the short-wavelength part of the spectrum.
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7

Uratani, Hiroki. "(Invited) Simulating Dynamic Excitons Via Quantum Molecular Dynamics: A Case Study in Lead Halide Perovskites." ECS Meeting Abstracts MA2022-01, no. 13 (July 7, 2022): 904. http://dx.doi.org/10.1149/ma2022-0113904mtgabs.

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The ultrafast electronic and structural dynamics invoked by photoexcitation, i.e., “dynamic exciton” phenomena, not only are important in the context of practical applications such as solar cells, but also raise many questions from the viewpoint of fundamental science. Experimental measurement, computational simulations, and theoretical interpretation will be the three pillars for deciphering the dynamic exciton phenomena. From the viewpoint of computational simulations, molecular dynamics (MD) techniques combined with quantum chemical calculations, i.e., quantum molecular dynamics (QMD), has been the popular tool to simulate the dynamic exciton phenomena. The quantum chemical calculations, which are typically conducted on the basis of the density-functional theory (DFT), require the large computational resources and time. These have been the limiting factors for the accessible spatial and time scales by the QMD simulations. To extend the coverage of simulations to more complex, large-scale systems, we have developed efficient excited-state QMD methods that can include nonadiabatic effects. Our method combines the density-functional tight binding (DFTB) method, which is an approximate DFT, and the surface hopping method, which is a theoretical framework to incorporate the nonadiabatic effects into the QMD simulations. The method was further improved to be suitable for condensed-phase simulations explicitly including the environment, i.e., solvent, by using a “divide-and-conquer” style quantum chemical calculation technique. These theoretical framework enables us to simulate the coupled electronic–structural dynamics in excited states of systems consisting of 102–103 atoms[1,2,3]. In addition, using the developed method, we conducted the real-time simulations of the ultrafast processes invoked by photoexcitation of lead iodide perovskites, which are known as the key materials for perovskite solar cells. The dissociation of the exciton into the positive and negative charge carriers was observed. Moreover, the hot carrier cooling, where the charge carriers dissipate excess energy via the electron–phonon coupling and relax to the band edges, was also tracked. Finally, the direct evidence of the polaron formation, where the structural deformation is induced by the presence of charge carriers, was observed. These results highlight the importance of the coupling between electronic and structural degrees of freedom. In the talk, recent improvements in the methodology and future perspectives will also be presented[5]. References [1] H. Uratani and H. Nakai, J. Chem. Phys. 152, 224109 (2020). [2] H. Uratani, T. Morioka, T. Yoshikawa, and H. Nakai, J. Chem. Theory Comput. 16, 7299 (2020). [3] H. Uratani, T. Yoshikawa, and H. Nakai, J. Chem. Theory Comput. 17, 1290 (2021). [4] H. Uratani and H. Nakai, J. Phys. Chem. Lett. 11, 4448 (2020). [5] H. Uratani and H. Nakai, J. Chem. Theory Comput. in press. Figure 1
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8

Kim, Sun-Kyo, and Yong-Seog Kim. "Charge carrier injection and transport in QLED layer with dynamic equilibrium of trapping/de-trapping carriers." Journal of Applied Physics 126, no. 3 (July 21, 2019): 035704. http://dx.doi.org/10.1063/1.5109089.

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9

Pfeiffer, Carl. "Semiconductor 1/f noise from dynamic coupling of charge carriers and lattice." Journal of Applied Physics 90, no. 7 (October 2001): 3653–55. http://dx.doi.org/10.1063/1.1388020.

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10

BRYKSIN, V. V., and P. KLEINERT. "DYNAMIC MAGNETOELECTRIC AND CHARGE-HALL EFFECTS IN THE RASHBA–DRESSELHAUS MODEL." International Journal of Modern Physics B 20, no. 29 (November 20, 2006): 4937–46. http://dx.doi.org/10.1142/s0217979206035680.

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In a biased two-dimensional electron gas, the presence of spin-orbit coupling of both the Rashba and Dresselhaus type leads to a Hall conductivity of charge carriers in the absence of an external magnetic field. We study the dynamical charge-Hall effect, the field-induced spin accumulation, and the magnetoelectric effect for a system with short-range elastic impurity scattering by analytically solving the kinetic equations for the spin-density matrix in the linear response regime. By tuning the strength of the Rashba and Dresselhaus spin-orbit coupling as well as the frequency and direction of the applied electric field, eigenmodes of the spin-coupled system are identified.
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11

LEE, Kyutae. "Probing of Carrier Motion and Contact Electrification by Using Electric-Field-Induced Second-Harmonic Generation." Physics and High Technology 30, no. 1/2 (February 28, 2021): 20–24. http://dx.doi.org/10.3938/phit.30.004.

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Triboelectric generation has attracted significant interest for its potential as an eco-friendly way to produce power with a greatly increasing power density, thereby opening the door to various applications. Although the triboelectricity effect is one of the oldest research areas and an enormous amount of effort has been put forth in developing it for many applications, its physical origin remains a mystery. Particularly, the complexity of triboelectrification causes the motion of charge carriers, including charge generation, charge separation, and other charging processes, to be vague. A novel approach based on optical second-harmonic generation technology has shown great promise in directly monitoring the dynamic performance of the triboelectricity effect and hence visualizing the spatial distribution of triboelectric charges. In this article, several works on the direct probing of carrier motion in organic transistors and in bulk heterojunction organic solar cells and of contact electrification by using an optical second-harmonic generation technique will be briefly introduced and discussed after second-harmonic generation and electric-field-induced second-harmonic generation have been described.
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12

Chernenkaya, A., A. I. Dmitriev, M. Kirman, O. V. Koplak, and R. B. Morgunov. "ESR Spectra of Charge Carriers in the α'- and β- Phases of (BEDT-TTF)2IBr2 Single Crystals." Solid State Phenomena 190 (June 2012): 615–18. http://dx.doi.org/10.4028/www.scientific.net/ssp.190.615.

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High-frequency dynamic magnetic properties of quasi-two-dimensional organic conductors (BEDT-TTF)2IBr2ofα'- andβ-phases have been studied by Electron Spin Resonance (ESR) spectroscopy. The heating of crystals in theα'-phase is accompanied by their phase transition to theβ-phase, so, the Dyson distortion of the ESR line is appeared. Contributions from the crystal field and symmetry of the system as well as the orbital magnetic moment admixture to the total magnetic moment of charge carriers have been judged by the comparison of the orientation and temperature dependencies of the ESR spectra for theα'- andβ-phases. Experimental data have proved localized states of charge carriers either inα'- orβ-phases.
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13

Pavlyshenko, B. M., and R. Ya Shuvar. "THE DYNAMIC OF CHARGE CARRIERS INTERACTION WITH TRAPPING CENTERS UNDER PHOTODEFORMATIONAL EXCITATION OF SEMICONDUCTOR." Sensor Electronics and Microsystem Technologies 2, no. 1 (October 17, 2014): 6–9. http://dx.doi.org/10.18524/1815-7459.2005.1.111976.

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14

Mulenos, Marina R., Henry Lujan, Lauren R. Pitts, and Christie M. Sayes. "Silver Nanoparticles Agglomerate Intracellularly Depending on the Stabilizing Agent: Implications for Nanomedicine Efficacy." Nanomaterials 10, no. 10 (September 30, 2020): 1953. http://dx.doi.org/10.3390/nano10101953.

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Engineered nanoparticles are utilized as drug delivery carriers in modern medicine due to their high surface area and tailorable surface functionality. After in vivo administration, nanoparticles distribute and interact with biomolecules, such as polar proteins in serum, lipid membranes in cells, and high ionic conditions during digestion. Electrostatic forces and steric hindrances in a nanoparticle population are disturbed and particles agglomerate in biological fluids. Little is known about the stability of nanoparticles in relation to particle surface charge. Here, we compared three different surface-stabilized silver nanoparticles (50 nm) for intracellular agglomeration in human hepatocellular carcinoma cells (HepG2). Nanoparticles stabilized with branched polyethyleneimine conferred a positive surface charge, particles stabilized with lipoic acid conferred a negative surface charge, and particles stabilized with polyethylene glycol conferred a neutral surface charge. Particles were incubated in fetal bovine serum, simulated lung surfactant fluid, and simulated stomach digestion fluid. Each nanoparticle system was characterized via microscopic (transmission electron, fluorescence, and enhanced darkfield) and spectroscopic (hyperspectral, dynamic light scattering, and ultraviolet-visible absorption) techniques. Results showed that nanoparticle transformation included cellular internalization, agglomeration, and degradation and that these changes were dependent upon surface charge and incubation matrix. Hyperspectral analyses showed that positively charged silver nanoparticles red-shifted in spectral analysis after transformations, whereas negatively charged silver nanoparticles blue-shifted. Neutrally charged silver nanoparticles did not demonstrate significant spectral shifts. Spectral shifting indicates de-stabilization in particle suspension, which directly affects agglomeration intracellularly. These characteristics are translatable to critical quality attributes and can be exploited when developing nano-carriers for nanomedicine.
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15

Sengupta, Rajarshi, Aditya S. Khair, and Lynn M. Walker. "Dynamic interfacial tension measurement under electric fields allows detection of charge carriers in nonpolar liquids." Journal of Colloid and Interface Science 567 (May 2020): 18–27. http://dx.doi.org/10.1016/j.jcis.2020.01.081.

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16

Li, Shunran, Po-Hsun Ho, Abram L. Falk, and Peijun Guo. "Ultrafast infrared plasmon switching in aligned carbon-nanotube optical resonators." Journal of Optics 24, no. 4 (March 7, 2022): 044009. http://dx.doi.org/10.1088/2040-8986/ac5809.

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Abstract Reconfigurable plasmonic materials are crucial components in active photonic devices for optical communication, signal processing, and sensing applications. Certain candidates including transparent conducting oxides, small-bandgap semiconductors (i.e. Ge, InSb), and conducting polymers can exhibit switchable free carrier concentrations triggered by optical, electrical or thermal excitations. Here, we show that aligned films of single-walled carbon nanotubes (SWCNTs) can serve as all-optically tunable plasmonic material in the mid-infrared range, thereby adding them to the library of switchable plasmonic materials. Interband optical pumping with femtosecond laser pulses results in the photoexcitation of free charge carriers, which transiently blueshifts the plasmon resonances of patterned, periodic SWCNT nano-resonators spanning the mid-infrared spectral range from 1700 to 2700 cm−1. The ultrafast plasmon modulation exhibits a nearly single-picosecond decay time, attributed to interband carrier relaxation and inter-tube charge transfer. Given that aligned films of SWCNTs have high thermal stability, excellent photostability, epsilon-near-zero property, and extremely large optical anisotropy, their dynamic tunability represents a promising pathway towards active optical devices in the technologically important mid-infrared range.
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17

Nolte, David, and Michael Melloch. "Bandgap and Defect Engineering for Semiconductor Holographic Materials: Photorefractive Quantum Wells and Thin Films." MRS Bulletin 19, no. 3 (March 1994): 44–49. http://dx.doi.org/10.1557/s0883769400039683.

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Bandgap engineering of thin semiconductor layers and defect engineering combine to form photorefractive (PR) quantum well structures. PR quantum wells are semi-insulating thin films useful for dynamic holography and other coherent and incoherent optical applications. As materials for thin-film dynamic holography, they have high nonlinear-optical sensitivity and high speed.The PR effect translates a spatially varying irradiance, from the interference of two or more coherent light beams, into a refractive index grating. The multiple-step PR process begins with photoexcitation of charge carriers, followed by transport and trapping of charge at deep defects. The trapped space-charge generates electric fields that alter the refractive index of the material through the electrooptic effect. The same laser beams that generate the gratings diffract from the gratings, leading to a rich variety of multiple-beam effects, such as two-wave and four-wave mixing.Because the PR process involves several distinct physical parameters, such as carrier mobility and electrooptic coefficients, optimized performance requires a coincidence of favorable properties in a single material. Rather than relying on coincidence, bandgap engineering of multiple layers of semiconductors provides a way to individually tune the separate material pa rameters. Likewise, defect engineering in semiconductors provides flexibility in the choice of defects, their concentrations, and degree of compensation. Bandgap and defect engineering combined make custom designed PR materials possible.
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18

Wei, Bin, Kenji Furukawa, Junko Amagai, Musubu Ichikawa, Toshiki Koyama, and Yoshio Taniguchi. "A dynamic model for injection and transport of charge carriers in pulsed organic light-emitting diodes." Semiconductor Science and Technology 19, no. 5 (March 23, 2004): L56—L59. http://dx.doi.org/10.1088/0268-1242/19/5/l04.

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19

Dzhuraev, Davron Rakhmanovich, and Akmal Atayevich Turaev. "FEATURES OF KEY PARAMETERS OF FIELD TRANSISTORS." Scientific Reports of Bukhara State University 3, no. 2 (February 28, 2019): 7–10. http://dx.doi.org/10.52297/2181-1466/2019/3/2/1.

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In this paper, the dependence of stock current on the channel closing voltage in the main parameters of the field transistor (stock), dynamic resistance and channel closing mode has been investigated. The optimal values of the channel thickness are determined depending on the thickness of the p+-n junction volume charge region of the gate and the concentration of carriers that provide high sensitivity.
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20

Seo, Dong-Bum, Tran Trung, Sung-Su Bae, and Eui-Tae Kim. "Improved Photoelectrochemical Performance of MoS2 through Morphology-Controlled Chemical Vapor Deposition Growth on Graphene." Nanomaterials 11, no. 6 (June 17, 2021): 1585. http://dx.doi.org/10.3390/nano11061585.

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The morphology of MoS2 nanostructures was manipulated from thin films to vertically aligned few-layer nanosheets on graphene, in a controllable and practical manner, using metalorganic chemical vapor deposition. The effects of graphene layer and MoS2 morphology on photoelectrochemical (PEC) performance were systematically studied on the basis of electronic structure and transitions, carrier dynamic behavior, and PEC measurements. The heterojunction quality of the graphene/vertical few-layer MoS2 nanosheets was ensured by low-temperature growth at 250−300 °C, resulting in significantly improved charge transfer properties. As a result, the PEC photocurrent density and photoconversion efficiency of the few-layer MoS2 nanosheets significantly increased upon the insertion of a graphene layer. Among the graphene/MoS2 samples, the few-layer MoS2 nanosheet samples exhibited shorter carrier lifetimes and smaller charge transfer resistances than the thin film samples, suggesting that vertically aligned nanosheets provide highly conductive edges as an efficient pathway for photo-generated carriers and have better electronic contact with graphene. In addition, the height of vertical MoS2 nanosheets on graphene should be controlled within the carrier diffusion length (~200 nm) to achieve the optimal PEC performance. These results can be utilized effectively to exploit the full potential of two-dimensional MoS2 for various PEC applications.
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21

Kobayashi, Yusuke, Tatsuya Nishiwaki, Akihiro Goryu, Tsuyoshi Kachi, Ryohei Gejo, Hiro Gangi, Tomoaki Inokuchi, and Kazuto Takao. "Improvement of Q rr –I DSS and dynamic avalanche of field-plate MOSFET by local lifetime control on the cathode side." Japanese Journal of Applied Physics 61, SC (February 18, 2022): SC1047. http://dx.doi.org/10.35848/1347-4065/ac40ac.

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Abstract Reducing the reverse recovery charge (Q rr) is effective for reducing switching loss in field plate (FP)-MOSFETs. A lifetime killer is utilized to reduce Q rr while increasing the leakage current in the off-state. Device simulation shows that a local lifetime killer on the cathode side successfully improves the trade-off between Q rr and I DSS in comparison with that of a uniform lifetime killer. A known issue of cathode lifetime killers is overshoot voltage by hard recovery. However, the overshoot voltage of FP-MOSFET decreases with a cathode lifetime killer owing to an internal snubber, which is a feature of FP-MOSFETs. An internal snubber with a large series resistance causes a dynamic avalanche by both the increase of FP potential and excess carriers in high-speed operation. The cathode lifetime killer also improves dynamic avalanche by excess carriers. Consequently, the cathode lifetime killer is preferable for high-speed FP-MOSFETs because the Q rr–I DSS trade-off and the trade-off between dynamic avalanche and I DSS are effectively improved.
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22

Barone, Carlo, and Sergio Pagano. "What Can Electric Noise Spectroscopy Tell Us on the Physics of Perovskites?" Coatings 11, no. 1 (January 17, 2021): 96. http://dx.doi.org/10.3390/coatings11010096.

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Electric noise spectroscopy is a non-destructive and a very sensitive method for studying the dynamic behaviors of the charge carriers and the kinetic processes in several condensed matter systems, with no limitation on operating temperatures. This technique has been extensively used to investigate several perovskite compounds, manganese oxides (La1−xSrxMnO3, La0.7Ba0.3MnO3, and Pr0.7Ca0.3MnO3), and a double perovskite (Sr2FeMoO6), whose properties have recently attracted great attention. In this work are reported the results from a detailed electrical transport and noise characterizations for each of the above cited materials, and they are interpreted in terms of specific physical models, evidencing peculiar properties, such as quantum interference effects and charge density waves.
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23

Johnson, K. D., and V. P. Dravid. "In Situ Electron Holography of Grain Boundary Schottky Barrier Dynamics in 0.5 Wt% NB Doped SrTiO3 36.8° Symmetric Tilt Bicrystals." Microscopy and Microanalysis 4, S2 (July 1998): 796–97. http://dx.doi.org/10.1017/s1431927600024107.

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Electrical phenomena such as positive temperature coefficient of resistance (PTCR), grain boundary layer capacitance, and varistors are controlled by Schottky barriers to current transport formed in grain boundary regions. These grain boundary potential barriers are a result of charged defect accumulation, either through equilibrium segregation or kinetic diffusion processes. Recent work on Nb and Mn doped BaTiO3 highlights the importance of substitutional defects which activate grain boundary trap states and give rise to the PTCR effect. The dynamic interaction of charge carriers with such trap states also produces the rapid electrical breakdown characteristic of varistors. This study explores the issues of defect species, space charge, and electrical transport in donor doped SrTi03 by electron holography and electron energy loss spectroscopy.The specific defect species and mechanisms of current transport through donor doped SrTiO3 remain unresolved because of the difficulty in connecting defect distributions (structural information) and resultant Schottky barrier effects (chemical information).
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Vargas, William E., Marcela Hernández-Jiménez, Victoria Quirós-Cordero, Esteban Avendaño, and Federico Muñoz-Rojas. "Optical, Charge Transport, Thermal, Magnetic, Plasmonic, and Quantum Mechanical Properties of Iridium." Recent Progress in Materials 04, no. 04 (October 12, 2022): 1–29. http://dx.doi.org/10.21926/rpm.2204019.

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Spectrophotometry has been widely used to retrieve the dielectric function of a bulk iridium sample using an extended version of the Drude–Lorentz model. The parameters of the model are optimized using a spectral-projected-gradient-method-assisted acceptance-probability-controlled simulated annealing approach. Furthermore, optimized values of Drude parameters corresponding to the optical response of electrons and holes (scattering frequency of electrons, the ratio between scattering frequencies of holes and electrons, the ratio between effective masses of electrons and holes, the ratio between the number densities of holes and electrons, and electron volume plasma frequency) are used to evaluate charge transport and magnetic properties. These include static and dynamic conductivities, intrinsic mean free paths, the effective mass of charge carriers and their number densities, Fermi velocities and energies, densities of states at Fermi energies, mobilities, specific heats, Hall’s coefficient, thermal conductivities, charge carrier coupling constant, paramagnetic and diamagnetic susceptibilities, and the number of Bohr magnetons. In addition, optimized resonance energy values of the Lorentz contribution to the dielectric function were compared with the background information provided by density-functional-theory calculations for iridium. A decomposition of the energy loss function was used as the starting point to calculate the effective numbers of bound electrons involved in interband transitions, as well as the densities of states at the final energies of the sets of transitions considered. The Drude–Lorentz model involves charge carrier parameters for both electrons and holes, as well as the resonance energies correlating with the energies associated with quantum transitions. To a large extent, several physical quantities calculated from optimized parameters exhibit values close to those obtained from measurements or by applying other models, including quantum mechanics formulations.
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Park, H., K. H. Lee, Y. B. Kim, S. B. Ambade, S. H. Noh, W. Eom, J. Y. Hwang, W. J. Lee, J. Huang, and T. H. Han. "Dynamic assembly of liquid crystalline graphene oxide gel fibers for ion transport." Science Advances 4, no. 11 (November 2018): eaau2104. http://dx.doi.org/10.1126/sciadv.aau2104.

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Colloidal dispersions with liquid crystallinity hold great promise for fabricating their superstructures. As an example, when graphene oxide (GO) sheets are assembled in the liquid crystalline state, they can turn into ordered macroscopic forms of GO such as fibers via the wet spinning process. Here, we report that by reinforcing intersheet interactions, GO liquid crystals (LCs) turn into mechanically robust hydrogels that can be readily drawn into highly aligned fibrillar structures. GO hydrogel fibers with highly aligned sheets (orientation factor, f = 0.71) exhibit more than twice the ionic conductivity compared to those with partially aligned structures (f = 0.01). The hierarchically interconnected two-dimensional nanochannels within these neatly aligned GOLC hydrogel fibers may facilitate controlled transport of charge carriers and could be potentially explored as cables for interconnecting biosystems and/or human-made devices.
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Jia, Beibei, Jun Zhou, Jiaxin Chen, Zixuan Zhang, Yang Wang, Zepeng Lv, and Kai Wu. "Interfacial Insight of Charge Transport in BaTiO3/Epoxy Composites." Nanomaterials 13, no. 3 (January 19, 2023): 406. http://dx.doi.org/10.3390/nano13030406.

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Space charge accumulation greatly influences the dielectric performance of epoxy composites under high voltage. It has been reported that nano-fillers can suppress the charge accumulation in the bulk of insulation materials. However, it is still unclear how the nano-fillers influence the charge distribution at the interface between the filler and polymeric matrix. In this work, the dielectric properties and the local dynamic charge mobility behavior at the interface of barium titanate/epoxy resin (BTO/EP) composites were investigated from both bulk and local perspectives based on the macroscopic test techniques and in-situ Kelvin probe force microscopy (KPFM) methods. Charge injection and dissipation behavior exhibited significant discrepancies at different interfaces. The interface between BTO and epoxy is easy to accumulates a negative charge, and nanoscale BTO (n-BTO) particles introduces deeper traps than microscale BTO (m-BTO) to inhibit charge migration. Under the same bias condition, the carriers are more likely to accumulate near the n-BTO than the m-BTO particles. The charge dissipation rate at the interface region in m-BTO/EP is about one order of magnitude higher than that of n-BTO/EP. This work offers experimental support for understanding the mechanism of charge transport in dielectric composites.
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Bomba, Andrii, Igor Moroz, and Mykhailo Boichura. "Constructing and analyzing mathematical model of plasma characteristics in the active region of integrated p-i-n-structures by the methods of perturbation theory and conformal mappings." Eastern-European Journal of Enterprise Technologies 5, no. 5 (113) (October 31, 2021): 51–61. http://dx.doi.org/10.15587/1729-4061.2021.243097.

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The results of mathematical modeling of stationary physical processes in the electron-hole plasma of the active region (i-region) of integral p-i-n-structures are presented. The mathematical model is written in the framework of the hydrodynamic thermal approximation, taking into account the phenomenological data on the effect on the dynamic characteristics of charge carriers of heating of the electron-hole plasma as a result of the release of Joule heat in the volume of the i-th region and the release of recombination energy. The model is based on a nonlinear boundary value problem on a given spatial domain with curvilinear sections of the boundary for the system of equations for the continuity of the current of charge carriers, Poisson, and thermal conductivity. The statement of the problem contains a naturally formed small parameter, which made it possible to use asymptotic methods for its analytical-numerical solution. A model nonlinear boundary value problem with a small parameter is reduced to a sequence of linear boundary value problems by the methods of perturbation theory, and the physical domain of the problem with curvilinear sections of the boundary is reduced to the canonical form by the method of conformal mappings. Stationary distributions of charge carrier concentrations and the corresponding temperature field in the active region of p-i-n-structures are obtained in the form of asymptotic series in powers of a small parameter. The process of refining solutions is iterative, with the alternate fixation of unknown tasks at different stages of the iterative process. The asymptotic series describing the behavior of the plasma concentration and potential in the region under study, in contrast to the classical ones, contain boundary layer corrections. It was found that boundary functions play a key role in describing the electrostatic plasma field. The proposed approach to solving the corresponding nonlinear problem can significantly save computing resources
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Qiu, Qingqing, Lingling Xu, Dejun Wang, Yanhong Lin, and Tengfeng Xie. "Study on dynamic properties of the photoexcited charge carriers at anatase TiO 2 nanowires/fluorine doped tin oxide interface." Journal of Colloid and Interface Science 501 (September 2017): 273–81. http://dx.doi.org/10.1016/j.jcis.2017.04.075.

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Katayama, Kenji, Kei Kawaguchi, Yuta Egawa, and Zhenhua Pan. "Local Charge Carrier Dynamics for Photocatalytic Materials Using Pattern-Illumination Time-Resolved Phase Microscopy." Energies 15, no. 24 (December 16, 2022): 9578. http://dx.doi.org/10.3390/en15249578.

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We showed two demonstrations of the local charge carrier dynamics measurements of photocatalytic materials using our recently developed time-resolved phase-contrast microscopic technique combined with the clustering analyses. In this microscopic time-resolved technique, we observed the charge carrier dynamics via the refractive index change instead of the luminescence or absorption change, where we could often observe non-radiative charge carrier processes such as charge carrier trapping and non-radiative relaxation. By the clustering analyses of all the pixel-by-pixel responses, we could extract various different charge carrier dynamics because photocatalytic materials have inhomogeneity on surfaces and the charge carrier behavior depends on the local structure and species. Even for typical photocatalytic materials, titanium oxide and hematite, we could recognize various charge carrier dynamics, which cannot be differentiated by the general fitting procedure for the averaged time response. We could categorize the surface-trapped charge carriers (holes and electrons) and bulk carriers in the nanosecond to millisecond order, which indicates that this analytical procedure will play an important role in understanding the charge carrier dynamics for various photocatalytic materials.
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Bryushinin, M. A., V. V. Kulikov, A. A. Petrov, I. A. Sokolov, R. V. Romashko, and Yu N. Kulchin. "Three modes of the nonstationary holographic current excitation in a gallium oxide crystal." Europhysics Letters 137, no. 2 (January 1, 2022): 26002. http://dx.doi.org/10.1209/0295-5075/ac47f5.

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Abstract We report the nonstationary holographic current excitation in a β-Ga2O3 crystal at light wavelength . The material demonstrates insulating properties and high transparency for visible light, but this, however, does not prevent the dynamic space-charge grating formation and the holographic current observation for various external electric fields —zero, dc and ac ones. The signal amplitude is measured and analyzed vs. the frequency of phase modulation, spatial frequency and electric field value. The main photoelectric parameters such as specific photoconductivity, sensor responsivity and diffusion length of carriers are determined for the blue region of spectrum.
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LIU, X. J., Z. AN, and S. J. XIE. "TRANSITION OF BIPOLARON TO POLARONS INDUCED BY MAGNETIC IMPURITIES IN CONJUGATED POLYMERS." International Journal of Modern Physics B 25, no. 12 (May 10, 2011): 1601–10. http://dx.doi.org/10.1142/s0217979211100400.

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Both polarons and bipolarons are composite particles with internal structures in nondegenerate conjugated polymers. A bipolaron is a spinless species with charge ±2|e|, while a polaron is a spin-bearing one (spin 1/2, charge ±|e|). Serving as charge carriers, they play an important role in the transport properties of polymer-based optoelectronic devices. By using a nonadiabatic dynamic method, the motion of a bipolaron under an external electric field is theoretically investigated in a conjugated polymer with magnetic impurities. Our results show that a bipolaron can pass through the magnetic impurities, or break down into two polarons with different spins, or be trapped by the magnetic impurities, depending on the width of the impurity region. When the width of the impurity region is comparable to the polaron width, the bipolaron is transformed into two polarons easily. As a polaron and a bipolaron possess different spin characteristics, the decomposition of bipolarons induced by the magnetic impurities may have important effect on the spin polarized transportation.
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32

El hat, A., R. Essajai, O. Aziz, A. Mortadi, M. Rouchdi, A. Mzerd, and M. Qjani. "Dynamic properties of a one-dimensional charge density wave compound in the presence of uncondensed-carriers: Insights from numerical experiences." Results in Physics 16 (March 2020): 102900. http://dx.doi.org/10.1016/j.rinp.2019.102900.

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33

Zaitsev, Anton D., Petr S. Demchenko, Dmitry V. Zykov, Ekaterina A. Korotina, Elena S. Makarova, Ivan L. Tkhorzhevskiy, Anastasiia S. Tukmakova, et al. "Optical and Galvanomagnetic Properties of Bi1-xSbx Thin Films in the Terahertz Frequency Range." Applied Sciences 10, no. 8 (April 15, 2020): 2724. http://dx.doi.org/10.3390/app10082724.

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We report results of galvanomagnetic and terahertz time-domain spectroscopy measurements on thin films of Bi 1 − x Sb x on polyimide and mica substrates with various antimony concentrations (x from 0 to 15 %) and film thickness (70, 150 nm). The resistivity, Hall coefficient and magnetoresistivity of the films were measured experimentally in the magnetic field of 0.65 T at room temperature. Mobility and concentration of electrons and holes in the film plane were calculated using the transport coefficients. The terahertz time-domain spectroscopy is used to measure the complex conductivity and permittivity of Bi 1 − x Sb x thin films on the dielectric substrates in the frequency range from 0.2 to 1 THz. The plasma frequency, relaxation time, DC conductivity and effective carrier mass were extracted from these data and evaluated as functions of the Sb concentration for different film thickness and substrate. We observed that the film magnetoresistivity decreases with increasing the Sb concentration and for most of the films the Hall coefficient is negative and depends on the external factors insignificantly. We show that the mobility of charge carriers weakly depends on Sb concentration, which confirms the assertion about the scattering of carriers on themselves and not on defects in the structure. It was revealed that film static and dynamic resistivity (conductivity) as well as dielectric permittivity depend on Sb content and the film thickness. The results may be used for development of various thermoelectric, electronic and optical devices, such as THz detectors or components which can control the properties of THz radiation.
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Mittal, Disha, Largee Biswas, and Anita Kamra Verma. "Redox resetting of cisplatin-resistant ovarian cancer cells by cisplatin-encapsulated nanostructured lipid carriers." Nanomedicine 16, no. 12 (May 2021): 979–95. http://dx.doi.org/10.2217/nnm-2020-0400.

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Aim: To sensitize cisplatin (Cis)-resistant ovarian cancer cells toward Cis using Cis-loaded nanostructured lipid carriers (CisNLCs). Materials & methods: CisNLCs were synthesized and characterized using dynamic light scattering, Fourier transform IR and x-ray diffraction (XRD). Sensitivity of PA-1 and CaOV3 cells to Cis and its biotoxicity were assessed. Further, expression of the Cis-resistance markers GSTPi and ATP7B, and apoptotic markers Bax, Bcl2 and Cas9 were quantified by real-time PCR. Results: The size of synthesized CisNLCs was approximately 179.3 ± 2.32 nm and surface charge was -33.9 ± 1.47 mV. IC50 was 210 μg/ml in PA-1 and 500 μg/ml in CaOV3. CisNLCs modulated reactive oxygen species levels in CaOV3 cells. Reduced GSTPi and decreased Cis efflux via ATP7B sequestration caused Cis to accumulate in cytoplasm, thereby augmenting apoptosis in cells. Conclusion: CisNLCs sensitize CaOV3 by redox resetting, indicating their immense therapeutic potential.
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Schnaider, Paula, Nuno Manoel Martins Dias Fouto, Maria Sylvia Macchione Saes, and Claudio Felisoni De Angelo. "COMPETIÇÃO NO SETOR DE TELEFONIA MÓVEL BRASILEIRO DOI:10.7444/fsrj.v3i2.88." Future Studies Research Journal: Trends and Strategies 3, no. 2 (December 20, 2011): 145–70. http://dx.doi.org/10.24023/futurejournal/2175-5825/2011.v3i2.88.

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Although there were 152 million mobile phones in Brazil as of January 2009, a research conducted by the International Communications Union in 2008 revealed that amongst the 154 countries surveyed, Brazilian users paid the most for the use of mobile phones. Between 2008 and 2009, Anatel introduced mobile number portability as a measure that would promote greater competition amongst operators. This article sought to evaluate the impacts of this policy on competition in the Brazilian mobile telephony segment, particularly as to fees charged. To this effect, both a static and a dynamic analytical framework were built, based on the Prisoners‟ Dilemma Game-Theoretic Model. Theoretical propositions were compared to empirical data related to the mobile fees charged in São Paulo and indicated that the implementation of the mobile number portability policy did not bring about the reduction of fees charged to consumers. This finding contradicts the price reduction phenomenon that occurred in other countries after implementing the portability policy and suggests the need for further rulings which pose to encourage carriers to charge lower fees.
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36

Axelevitch, Alexander. "Hot-Probe Characterization of Transparent Conductive Thin Films." Materials 14, no. 5 (March 3, 2021): 1186. http://dx.doi.org/10.3390/ma14051186.

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Transparent conductive oxide (TCO) thin films represent a large class of wide-bandgap semiconductors applied in all fields of micro- and optoelectronics. The most widespread material applied for the creation of TCO coatings is indium-tin oxide (ITO). At the same time, there are plurality trends to change the high-cost ITO on other materials, for example, on the ZnO doped by different elements such as Al, Mn, and Sb. These films require mobile and low-cost evaluation methods. The dynamic hot-probe measurement system is one of such techniques that can supplement and sometimes replace existing heavy systems such as the Hall effect measurements or the Haynes–Shockley experiments. The theoretical basis and the method of analysis of the recorded dynamic hot-probe characteristics measured at different temperatures were presented in this work. This method makes it possible to extract the main parameters of thin films. Commercial thin ITO films and new transparent conducting ZnO:Al layers prepared by magnetron co-sputtering were studied by the proposed method. The measured parameters of commercial ITO films are in agreement with the presented and reference data. In addition, the parameters of ZnO:Al thin films such as the majority charge carriers type, concentration, and mobility were extracted from dynamic hot-probe characteristics. This method may be applied also to other wide-bandgap semiconductors.
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37

Hwang, Jih-Dar, Po-Ying Chen, Shang-Wu Ding, and Chi Wi Ong. "Effect of Noncovalent Dispersion of Poly(Ethylene Oxide) in Columnar Polyether-Based Discotic Liquid Crystal on the Ionic Conductivity and Dynamics of Lithium Ions." Crystals 9, no. 12 (November 28, 2019): 627. http://dx.doi.org/10.3390/cryst9120627.

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The ionic conductivity of an electrolyte is represented by a product of carrier density, charge (electric), and ionic mobility. The overall goal of this study was to provide an insight into the influence of lithium ion conductivity and dynamic when a continuous discotic liquid crystal (DLC) matrix of hexaazatrinapthylene-polyether, HATN-TEG-1, is doped with a small amount of polyethylene oxide (PEO, 5% of MW 8000). The favorable non-covalent interactions between PEO and the DLC triethylene glycol side-chains is supported by the maintenance of the mesophase. The lithium ionic conductivity of HATN-TEG-1 was found to be 1.1 × 10−6 S cm−1, which is better than the corresponding HATN-TEG-1-5%PEO-8000 with a value of 6.06 × 10−7 S cm−1. These results are further supported by the dynamics of the lithium ions in HATN-TEG-1 and HATN-TEG-1-5%PEO-8000 as characterized by 7Li, and 1H NMR spin-lattice relaxation time and self-diffusion coefficient measurements. Though the additional PEO was found to increase the ion carriers, the significant lowering of the ionic conductivity may be attributed to the more pronounced decrease of the mobility of the ionic part when the HATN-TEG-1 matrix is dispersed with PEO. This finding indicates that the doping of 5% PEO onto the matrix of HATN-TEG-1 DLC has an adverse effect on both its diffusion rate and ion conductivity.
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38

Pankratov, E. L., and E. A. Bulaeva. "Diagnostics of Possibility to Increase Prediction of Dynamic of Charge Carriers in A P-N-Junction with Optimized Distributions of Dopants." Universal Journal of Applied Mathematics 1, no. 1 (July 2013): 17–31. http://dx.doi.org/10.13189/ujam.2013.010104.

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39

Ohta, Kaoru, Yuichi Hiramatsu, Kohtaro Takahashi, Mitsuharu Suzuki, Hiroko Yamada, and Keisuke Tominaga. "Dynamic behavior of photogenerated charge carriers in diketopyrrolopyrrole-linked tetrabenzoporphyrin-based bulk heterojunction thin films probed with time-resolved terahertz spectroscopy." Journal of Photochemistry and Photobiology A: Chemistry 400 (September 2020): 112693. http://dx.doi.org/10.1016/j.jphotochem.2020.112693.

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40

Dai, Li, Shanshan Jiao, Chao Xu, Dayong Li, Jiaqi Lin, and Yuheng Xu. "Enhancement of blue photorefractive properties in Mg:Fe:Cu:SLiNbO3 crystals with near stoichiometry." Modern Physics Letters B 28, no. 05 (February 18, 2014): 1450038. http://dx.doi.org/10.1142/s0217984914500389.

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Using the top seeded solution growth technique, near stoichiometric Mg : Fe : Cu : SLiNbO 3 crystals have been grown by using K 2 O as flux. Infrared transmission spectra were measured and defect structure and change of threshold value were investigated. Using Kr + laser as light source (blue light with wavelength of 476 nm) the photorefractive properties of crystals were measured. The diffraction efficiency of 76.3%, the short response time of 11 s, the dynamic range of 27.39, the sensitivity of 2.09 cm/J, and the refractive index change of 8.67 × 10-5 were obtained. The blue photorefractive properties were enhanced. As the holes are the dominant charge carriers, the short wavelength blue light which exhibits high energy can excite the holes from both of the shallow and the deep trap centers with the same phase. It was found that the so-called optical damage-resistant dopant such as Mg 2+ ions no longer functioned as the damage resistant at 476 nm wavelength, but turned to enhance the blue photorefractive characteristics.
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41

Slussarenko, Sergei S., Elena A. Melnikova, and Alexei L. Tolstik. "Recording the dynamic polarisation gratings in pure nematic liquid crystal." Journal of the Belarusian State University. Physics, no. 1 (February 1, 2022): 14–19. http://dx.doi.org/10.33581/2520-2243-2022-1-14-19.

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We report on experimental realisation of polarisation dynamic gratings recording in pure nematic liquid crystal. This work is devoted to the experimental implementation of writing polarisation dynamic gratings in a pure nematic liquid crystal. The registration mechanism is based on the photorefractive effect in a cell filled with a pure nematic crystal under the action of an applied constant electric field. This phenomenon does not require the presence of photoexcited charge carriers in the liquid crystal and is explained by the extremely high anisotropy of the liquid crystal. The article provides an elementary theoretical model of this process. The dependences of the grating writing process on the spatial frequency of the interference field and the intensity of the recording beams are investigated. It was found that the spatial grating does not coincide with the interference field – the response of the medium is non-local. However, we do not associate this property with that in photorefractive crystals. In our case, a mechanism of purely geometric mismatch is more likely due to the peculiarity of the recording mechanism. One of the fundamental properties of the described processes is their independence from the wavelength of the recording radiation, which confirms the model of the recording mechanism we have chosen.
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Akhlaghi, Milad, Lida Eftekharivash, Mohammad Taebpour, Saeid Afereydoon, Marziyeh Ebrahimpour, Maryam Zarezadeh Mehrizi, Mahboobeh Zarezadeh Mehrizi, and Bibi fatemeh Haghirosadat. "Improving the Therapeutic Performance of Glycyrrhiza Glabra Hydroalcoholic Extract Using Liposomal Nano-carriers and Their Characterization." Disease and Diagnosis 11, no. 2 (April 1, 2022): 39–48. http://dx.doi.org/10.34172/ddj.2022.09.

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Background: The use of plants as therapeutic drugs has long been common among human beings. The Glycyrrhiza glabra is one of the medicinal plants with many therapeutic properties. However, using this herb in traditional methods faces some challenges. The use of pharmaceutical nano-carriers such as liposomes is one of the new strategies to overcome these challenges. In this regard, the current study aimed to synthesize and characterize liposomal nano-carriers containing the G. glabra hydroalcoholic extract to improve its therapeutic effects. Materials and Methods: After the extraction of the G. glabra root by the Soxhlet method, nano-liposomes containing G. glabra extracts were synthesized by the thin-film preparation method. Then, the encapsulation efficiency (EE) rate and drug release pattern of nanoliposome were examined using the spectrophotometry method. Next, physicochemical properties such as size, zeta potential, morphology, and non-interaction of the nano-system with the extract were investigated by dynamic-light-scattering (DLS), atomic force microscope (AFM), and Fourier transform infrared spectroscopy (FTIR) methods, and finally, the toxicity of the nano-system on human foreskin fibroblast cells was assessed using the MTT method. Results: Nano-liposomes containing licorice extracts with the EE of 2.3±75.32% were from the type of slow release and controlled release, having a size of 111.4±1.2 nm, a surface charge of -53.6±6.3, and a dispersion index of 0.210±0.13, and they had no interaction with the loaded extract. The results of the MTT test also demonstrated that the synthesized nano-liposomes were non-toxic on normal cells. Conclusion: Overall, the findings proved that synthesized nano-liposomes with proper physicochemical properties can be a suitable carrier for the G. glabra extract and thus cause stability and improve the therapeutic effects of this herbal extract as a medicinal plant.
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43

Tikhomirov, S. A. "Ultrafast dynamics and mechanisms of non-stationary absorption in thin gallium selenide samples." Proceedings of the National Academy of Sciences of Belarus. Physics and Mathematics Series 57, no. 1 (April 2, 2021): 99–107. http://dx.doi.org/10.29235/1561-2430-2021-57-1-99-107.

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Herein, the dynamics and mechanisms of induced absorption in thin samples of gallium selenide under various excitation conditions are studied using femtosecond kinetic spectroscopy. We have registered several types of induced changes including induced absorption on free charge carriers (“hot” and thermalized electrons), bleaching and absorption due to the population of near-edge trap or exciton states, as well as rapid changes in the absorption of probing radiation in the region of the overlap of the exciting and probing pulses due to two-quantum two-frequency interband transitions. The time ranges of the relaxation processes are estimated. It is shown that when using relatively low-intensity long-wave excitation (790 nm), the resonant excitation of the near-edge states occurs mainly due to two-quantum two-frequency transitions followed by the formation of the dynamic equilibrium between bound and free electrons in the time range up to 5 ps. When electrons are excited deeply into the conduction band with the formation of hot free electrons and their subsequent thermalization to the bottom of the conduction band in the time range up to 1 ps, the population of the near-edge states and the establishment of the dynamic equilibrium between bound and free electrons is realized in the same time range (5 ps) as when they are excited “from below”.
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44

Popov, V. M. "Determination of the diffusion length of minority charge carriers in a semiconductor from the dynamic nonequilibrium I–V characteristics of MIS structures." Semiconductors 48, no. 7 (July 2014): 875–82. http://dx.doi.org/10.1134/s1063782614070161.

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45

Wei, Xiao, Tengfeng Xie, Dan Xu, Qidong Zhao, Shan Pang, and Dejun Wang. "A study of the dynamic properties of photo-induced charge carriers at nanoporous TiO2/conductive substrate interfaces by the transient photovoltage technique." Nanotechnology 19, no. 27 (May 28, 2008): 275707. http://dx.doi.org/10.1088/0957-4484/19/27/275707.

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46

Wang, Zijun, Wenying Zhou, Xuezhen Sui, Lina Dong, Qingguo Chen, Jing Zuo, and Huiwu Cai. "Dynamic thermal-dielectric behavior of core-shell–structured aluminum particle-reinforced epoxy composites." High Performance Polymers 29, no. 1 (July 28, 2016): 3–12. http://dx.doi.org/10.1177/0954008315624496.

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The broadband dielectric spectroscopy was carried out in the frequency range of 1–107 Hz at the −20–200°C range to investigate the effect of temperature on the dynamic thermal–dielectric behavior of the aluminum (Al)/epoxy composite. The epoxy composites with core-shell–structured Al particles were prepared by solution method. The results show that the dielectric permittivity of the composites increased smoothly with a rise of filler content and reduced with an increase in frequency at room temperature. While the dielectric loss and conductivity still remained at low level owing to the nanoscale alumina insulating shell serving as a barrier layer to control the dielectric loss. The dielectric permittivity, dissipation factor, and conductivity of the composites increased with temperature and exhibited an abrupt rise around the glass transition temperature ( Tg). A large increase in the dissipation factor and conductivity with temperature is attributed to the direct current conduction of thermal-activated charge carriers resulting from pure epoxy above Tg. The observed temperature-dependent dielectric relaxations of the composites indicated a thermally activated behavior of the relaxation time of epoxy chain segments.
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47

RENGEL, RAUL, TOMAS GONZALEZ, and MARIA J. MARTIN. "ON THE INFLUENCE OF SPACE-QUANTIZATION EFFECTS ON THE RF NOISE BEHAVIOUR OF DG MOSFETS." Fluctuation and Noise Letters 04, no. 04 (December 2004): L561—L569. http://dx.doi.org/10.1142/s0219477504002191.

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We present a particle-based Monte Carlo investigation of the high frequency noise behavior of a double gate MOSFET. The effective potential approach has been considered for the description of vertical quantum confinement of carriers within the channel. The intrinsic noise sources and the main circuital noise parameters are studied, together with the static and dynamic parameters, thus allowing to provide a full comprehension of the inner physics of the device and elucidating the consequences of quantum mechanical space-quantization effects (like charge repulsion from the gate-oxide boundaries). Results show that neglecting quantum phenomena leads to an important overestimation of gate capacitance and device transconductance and an underestimation of the final influence of induced gate noise (via the normalized parameter R) on the circuital noise parameters at RF and microwave frequency ranges.
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48

Melnikova, E. V., D. V. Goryachev, A. A. Chaplenko, M. A. Vodyakova, A. R. Sayfutdinova, and V. A. Merkulov. "Development of liposomal drug formulations: quality attributes and methods for quality control." NANOMEDICINE, no. 6 (December 31, 2018): 33–39. http://dx.doi.org/10.24075/brsmu.2018.092.

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The use of nanostructured components in drug manufacturing and, more specifically, targeted drug delivery has recently become a major trend in the pharmaceutical industry. Nanodrugs encompass a wide range of pharmaceutical agents containing dendrimers, nanocrystals, micelles, liposomes, and polymer nanoparticles. Liposomes are the most well-studied nanoparticles and effective drug carriers. However, the more complex their structure is, the more process controls are needed and the more quality attributes have to be monitored, including the chemical properties of the liposomal fraction such as the shape, size and charge of the nanoparticle, conjugation efficacy, and distribution of the active ingredient. We believe that quality control of key liposome characteristics should rely on dynamic and laser light scattering coupled with electrophoresis, differential scanning calorimetry, cryo-electron microscopy, nuclear magnetic resonance, laser diffraction analysis, and gel filtration chromatography.
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49

Tanashyan, M. M., R. B. Medvedev, O. V. Lagoda, E. S. Berdnikovich, S. I. Skrylev, E. G. Gemdzhian, and M. V. Krotenkova. "The state of cognitive functions after angioreconstructive operations on the carotid arteries." IMMUNO-ONCOLOGY, no. 5 (September 16, 2019): 65–71. http://dx.doi.org/10.24075/brsmu.2019.059.

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The use of nanostructured components in drug manufacturing and, more specifically, targeted drug delivery has recently become a major trend in the pharmaceutical industry. Nanodrugs encompass a wide range of pharmaceutical agents containing dendrimers, nanocrystals, micelles, liposomes, and polymer nanoparticles. Liposomes are the most well-studied nanoparticles and effective drug carriers. However, the more complex their structure is, the more process controls are needed and the more quality attributes have to be monitored, including the chemical properties of the liposomal fraction such as the shape, size and charge of the nanoparticle, conjugation efficacy, and distribution of the active ingredient. We believe that quality control of key liposome characteristics should rely on dynamic and laser light scattering coupled with electrophoresis, differential scanning calorimetry, cryo-electron microscopy, nuclear magnetic resonance, laser diffraction analysis, and gel filtration chromatography.
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50

Heitjans, Paul, and Martin Wilkening. "Ion Dynamics at Interfaces: Nuclear Magnetic Resonance Studies." MRS Bulletin 34, no. 12 (December 2009): 915–22. http://dx.doi.org/10.1557/mrs2009.213.

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AbstractInterface engineering and the study of diffusion and transport processes through and along interfacial regions play important roles in materials science and energy research. For the latter, nanostructured materials are increasingly considered to act as powerful electrodes and solid electrolytes in sustainable energy systems, such as Li ion batteries. This is due to reduced diffusion lengths achieved when going to the nanometer scale and the fact that nanocrystalline materials with an average particle size of less than about 50 nm often show an enhanced diffusivity of their charge carriers. In this article, we show examples of how solid-state nuclear magnetic resonance (NMR) spectroscopy can be used to study the diffusion parameters of Li cations located in the interfacial regions separately from those in the interior of the grains. This article will demonstrate the future challenges and perspectives of Li NMR as a powerful tool of probing dynamic properties in functional materials.
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