Journal articles: 'Space charge doping'

1

Liu, Peng, Xi Pang, Zongliang Xie, Tianlei Xu, Shifeng Shi, Peng Wu, He Li, and Zongren Peng. "Space charge characteristics in epoxy/nano-MgO composites: Experiment and two-dimensional model simulation." Journal of Applied Physics 132, no. 16 (October 28, 2022): 165501. http://dx.doi.org/10.1063/5.0104268.

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Space charge accumulation in polymer dielectrics may lead to serious electric field distortion and even insulation failure during long-term operations of power equipment and electronic devices, especially under conditions of high temperature and direct current electric stress. The addition of nanoparticles into polymer matrices has been found effective in suppressing space charge accumulation and alleviating electric field distortion issues. Yet, the underlying mechanisms of nanoparticle doping remain a challenge to explore, especially from multi-dimensional composite insights. Here, a two-dimensional bipolar charge transport model with consideration of interface zones between organic/inorganic phases is proposed for the investigation into space charge behaviors of nanodielectrics. To validate the effectiveness and feasibility of the model, pulsed electroacoustic experiments are performed on epoxy/nano-MgO composites with different doping ratios of nanoparticles. Experimental observations match well with simulation anticipations, i.e., higher doping ratios of nanoparticles below the percolation threshold exhibit better capabilities to inhibit space charge accumulation. The deep traps (∼1.50 eV) generated in the interface zones are demonstrated to capture free charges, forming a reverse electric field in the region adjacent to electrodes and impeding the space charge migration toward the interior of the composite. This model is anticipated to provide theoretical insight for understanding space charge characteristics in polymer nanodielectrics and computing charge dynamics in extreme conditions where experiments are challenging to perform.

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Utamuradova, Sh B., and E. M. Naurzalieva. "SIMULATION OF POTENTIAL DISTRIBUTIONS IN THE SPACE CHARGE REGION OF SEMICONDUCTOR STRUCTURES." SEMOCONDUCTOR PHYSICS AND MICROELECTRONICS 3, no. 2 (April 30, 2021): 41–46. http://dx.doi.org/10.37681/2181-1652-019-x-2021-2-7.

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The methods of description of semiconduc tor-insulator interface characteristics based on process change of MIS type structure was considered. By using Maple Software, the calculations of quantities of inversion layer charge , total charge of semiconductor, inversion layer width and SCR semiconductor total width were m ade. Also, dependence theses quantities from doping level, temperature and surface potential were obtained

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Jin, Xin, and Hai Wang. "Space Charge Limited Current and Magnetoresistance in Si." Advanced Materials Research 750-752 (August 2013): 952–55. http://dx.doi.org/10.4028/www.scientific.net/amr.750-752.952.

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Mott and Gurney point out1, for defect-free semiconductors, I-V curve deviates from linear Ohmic type to nonlinear space-charge limited behavior at high electric field. A surprising large magnetoresistance (MR) has been reported in space-charge limited region by Delmo2-4recently. In present work, I-V and MR curves of silicon samples with different doping concentration are measured. It is observed that I-V curve enters into space charge region at lower voltage in heavily doped samples, however, space-charge limited current is absent in lightly doped samples. Two samples show different types of MR curve. In heavily doped samples, 8% MR is acquired at 3kG and the value of MR increases linearly up to 17%, while MR increases slowly up to 11% in lightly doped samples. It is believed that the dopant and trap in N-type silicon has a strong influence on the space-charge limited current and MR.

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4

Chen, Inan. "Theoretical analyses of space-charge doping in amorphous semiconductor superlattices. I. Doping superlattices." Physical Review B 32, no. 2 (July 15, 1985): 879–84. http://dx.doi.org/10.1103/physrevb.32.879.

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5

Chen, Inan. "Space charge doping effects in amorphous semiconductor multi-layers." Journal of Non-Crystalline Solids 77-78 (December 1985): 1093–96. http://dx.doi.org/10.1016/0022-3093(85)90848-8.

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6

Kabalan, Amal. "Controlling the Doping Depth in Silicon Micropillars." Applied Sciences 10, no. 13 (July 1, 2020): 4581. http://dx.doi.org/10.3390/app10134581.

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Micropillar arrays with radial p–n junctions are attractive for photovoltaic applications, because the light absorption and carrier collection become decoupled. The main challenge in manufacturing radial p–n junctions is achieving shallow (dopant depth <200 nm) and heavy doping (>1020 cm−3) that will allow the formation of a quasi-neutral region (QNR) and space charge region (SCR) in its tiny geometry. This experimental study investigates an approach that allows shallow and heavy doping in silicon micropillars. It aims to demonstrate that silicon dioxide (SiO2) can be used to control the dopant penetration depth in silicon micropillars.

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Vermeersch, Rémy, Gwénolé Jacopin, Bruno Daudin, and Julien Pernot. "DX center formation in highly Si doped AlN nanowires revealed by trap assisted space-charge limited current." Applied Physics Letters 120, no. 16 (April 18, 2022): 162104. http://dx.doi.org/10.1063/5.0087789.

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Electrical properties of silicon doped AlN nanowires grown by plasma assisted molecular beam epitaxy were investigated by means of temperature dependent current–voltage measurements. Following an Ohmic regime for bias lower than 0.1 V, a transition to a space-charge limited regime occurred for higher bias. This transition appears to change with the doping level and is studied within the framework of the simplified theory of space-charge limited current assisted by traps. For the least doped samples, a single, doping independent trapping behavior is observed. For the most doped samples, an electron trap with an energy level around 150 meV below the conduction band is identified. The density of these traps increases with a Si doping level, consistent with a self-compensation mechanism reported in the literature. The results are in accordance with the presence of Si atoms that have three different configurations: one shallow state and two DX centers.

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Nath, Chandrani, and A. Kumar. "Doping level dependent space charge limited conduction in polyaniline nanoparticles." Journal of Applied Physics 112, no. 9 (November 2012): 093704. http://dx.doi.org/10.1063/1.4763362.

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9

Ahmad, Ashfaq, Pawel Strak, Pawel Kempisty, Konrad Sakowski, Jacek Piechota, Yoshihiro Kangawa, Izabella Grzegory, et al. "Polarization doping—Ab initio verification of the concept: Charge conservation and nonlocality." Journal of Applied Physics 132, no. 6 (August 14, 2022): 064301. http://dx.doi.org/10.1063/5.0098909.

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In this work, we study the emergence of polarization doping in AlxGa1−xN layers with graded composition from a theoretical viewpoint. It is shown that bulk electric charge density emerges in the graded concentration region. The magnitude of the effect, i.e., the relation between the polarization bulk charge density and the concentration gradient is obtained. The appearance of mobile charge in the wurtzite structure grown along the polar direction was investigated using the combination of ab initio and drift-diffusion models. It was shown that the ab initio results can be recovered precisely by proper parameterization of drift-diffusion representation of the complex nitride system. It was shown that the mobile charge appears due to the increase of the distance between opposite polarization-induced charges. It was demonstrated that, for sufficiently large space distance between polarization charges, the opposite mobile charges are induced. We demonstrate that the charge conservation law applies for fixed and mobile charge separately, leading to nonlocal compensation phenomena involving (i) the bulk fixed and polarization sheet charge at the heterointerfaces and (ii) the mobile band and the defect charge. Therefore, two charge conservation laws are obeyed that induces nonlocality in the system. The magnitude of the effect allows obtaining technically viable mobile charge density for optoelectronic devices without impurity doping (donors or acceptors). Therefore, it provides an additional tool for the device designer, with the potential to attain high conductivities: high carrier concentrations can be obtained even in materials with high dopant ionization energies, and the mobility is not limited by scattering at ionized impurities.

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10

Peña-Camargo, Francisco, Jarla Thiesbrummel, Hannes Hempel, Artem Musiienko, Vincent M. Le Corre, Jonas Diekmann, Jonathan Warby, et al. "Revealing the doping density in perovskite solar cells and its impact on device performance." Applied Physics Reviews 9, no. 2 (June 2022): 021409. http://dx.doi.org/10.1063/5.0085286.

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Traditional inorganic semiconductors can be electronically doped with high precision. Conversely, there is still conjecture regarding the assessment of the electronic doping density in metal-halide perovskites, not to mention of a control thereof. This paper presents a multifaceted approach to determine the electronic doping density for a range of different lead-halide perovskite systems. Optical and electrical characterization techniques, comprising intensity-dependent and transient photoluminescence, AC Hall effect, transfer-length-methods, and charge extraction measurements were instrumental in quantifying an upper limit for the doping density. The obtained values are subsequently compared to the electrode charge per cell volume under short-circuit conditions ([Formula: see text]), which amounts to roughly 1016 cm−3. This figure of merit represents the critical limit below which doping-induced charges do not influence the device performance. The experimental results consistently demonstrate that the doping density is below this critical threshold (∼1012 cm−3, which means ≪ [Formula: see text]) for all common lead-based metal-halide perovskites. Nevertheless, although the density of doping-induced charges is too low to redistribute the built-in voltage in the perovskite active layer, mobile ions are present in sufficient quantities to create space-charge-regions in the active layer, reminiscent of doped pn-junctions. These results are well supported by drift–diffusion simulations, which confirm that the device performance is not affected by such low doping densities.

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11

Garba, I. I., R. Nasiru, Y. M. Abubakar, and U. Shehu. "Modeling and Bulk Characterization of 4HSIC Radiation Detector in Sentaurus TCAD Simulation Environment." Dutse Journal of Pure and Applied Sciences 10, no. 1c (April 24, 2024): 201–10. http://dx.doi.org/10.4314/dujopas.v10i1c.19.

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This paper gives an insight into the need for radiation detection and the most commonly flexible and efficient radiation detector. It also examines bulk characteristics of 4H-SiC semiconductor radiation detector with Ni and Ti as metals for the contact. Bulk characterization of the device, including: doping concentration, electrons and holes behaviors, space charge and current densities were carried out. The modeling is conducted using Sentaurus Technology Computer Aided Design (TCAD) to examine charge transport in bulk 4HSiC material. Data obtained were further analyzed through Sentaurus visual, sentaurus Techplot and Excel to clearly determine the characteristics of the device. It is observed that when the semiconductor and metal are in contact, the Fermi-level is established where the doping concentration varied with either magnitude of the doping concentration or nature of the dopant. Similarly, Schottky and ohmic contacts and temperature effect were observed from the device characteristics which demonstrate that, the detector can withstand a temperature from the range of 100K to 700K in no fluctuating state.

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12

Yoon, Seok Hyun, and Hwan Kim. "Experimental evidence for space charge segregation in Nb-doped BaTiO3." Journal of Materials Research 16, no. 5 (May 2001): 1479–86. http://dx.doi.org/10.1557/jmr.2001.0206.

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There is ample experimental evidence demonstrating space charge segregation in acceptor-doped BaTiO3. However there is still some controversy regarding donor-doped BaTiO3. Considering the space charge segregation theory in BaTiO3, the calculated driving force for space charge segregation is larger in acceptor-doped cases than in donor-doped cases. This result explains why acceptor segregation can be easily detected. However, a significant concentration of donors can also cause donor segregation. In donor and acceptor codoped BaTiO3, the grain sizes are very small, and donor segregation can be detected for compositions inducing a large space charge potential. In addition, in compositions that induced a small space charge potential, the grain sizes are very large, and donor segregation is not detected, although the total doping concentration is larger. This phenomenon means that donor segregation is caused by the space charge potential rather than misfit strain energy.

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13

Xing, Zhaoliang, Xiangnan Hu, Yujia Liu, Ming Hao, Chong Zhang, Chuncheng Hao, and Qingquan Lei. "Effect of CNFs-Ni/LDPE electrode on space charge injection in LDPE insulating layer." Journal of Physics: Conference Series 2334, no. 1 (August 1, 2022): 012006. http://dx.doi.org/10.1088/1742-6596/2334/1/012006.

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Abstract The accumulation of space charge is considered to be an important key factor to accelerate the aging of the insulation of HVDC cables. How to reduce the accumulation of space charge in the insulation layer is an urgent problem to improve the voltage level of cables. In this paper, an approach is presented to prevent charge from the inner semiconductive layer to the insulating layer, using a modified semiconductive compound by doping magnetic carbon nanofibers. Through microwave-assisted heating, Ni was deposited on the surface of carbon nanofibers which have been pre-treated. Modified semiconductive compound electrodes was used to test the injection of charges. The results showed that charge injected into LDPE insulting layerwith modified CNFs-Ni/ LDPE electrode is less than that with LDPE semiconductive layer without CNFs-Ni electrode.

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14

Kang, Wenbin, Shaoxing Meng, Haozhe Cui, Yuwei Li, Rui Mi, Chenyu Yan, Shijun Li, and Daomin Min. "Space Charge Accumulation in Silicone Rubber Influenced by Poole-Frenkel Effect." MATEC Web of Conferences 238 (2018): 01001. http://dx.doi.org/10.1051/matecconf/201823801001.

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With the rapid increase of electrical energy consumption in metropolises, more and more power cables are utilized in power grid or urban power network to transmit and distribute electrical energy. Silicone rubber is widely used as polymeric insulating materials of power cable accessories due to their excellent electrical and thermal performances. However, under high dc electric field space charges can accumulate inside the silicone rubber, which will distort the electric field in the bulk of the material, influencing the reliability and safety of operation. A bipolar charge injection and transport model is adopted to investigate the accumulation of space charges and distortion of electric field in silicone rubber. It is found that when charge injection rate is higher than the charge migration rate, space charges will accumulate in the material and the accumulation increases with an increase in electric field. The influence of the Poole-Frenkel effect is then studied. It is found that stronger Poole-Frenkel effect can enhance the nonlinearity of effective carrier mobility of silicone rubber, reducing the accumulation of space charges. This indicates that tuning the nonlinearity of effective carrier mobility by nano-doping can suppress space charges, improving the reliability of power cable accessories.

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15

HOVSEPYAN, RUBEN, ARMEN POGHOSYAN, and EDUARD VARDANYAN. "CHARGE WAVES IN DOUBLE DOPED PHOTOCHROMIC LITHIUM NIOBATE CRYSTALS." International Journal of Modern Physics: Conference Series 15 (January 2012): 54–60. http://dx.doi.org/10.1142/s2010194512006952.

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We are presenting the experimental studies of time-space characteristics of photochromic effect in lithium niobate crystals with double doping. The photoinduced autowaves of absorption coefficient changes under the light illumination of limited part of crystal were found. An analytical model is proposed for the explanation of appearance and spreading of charge waves.

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16

UNTERREITER, A. "The quantum zero space charge model for semiconductors." European Journal of Applied Mathematics 10, no. 4 (August 1999): 395–415. http://dx.doi.org/10.1017/s0956792599003824.

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The thermal equilibrium state of a bipolar, isothermal quantum fluid confined to a bounded domain Ω⊂ℝd, d = 1, 2 or d = 3 is the minimizer of the total energy [Escr ]ελ; [Escr ]ελ involves the squares of the scaled Planck's constant ε and the scaled minimal Debye length λ. In applications one frequently has λ2[Lt ]1. In these cases the zero-space-charge approximation is rigorously justified. As λ → 0, the particle densities converge to the minimizer of a limiting quantum zero-space-charge functional exactly in those cases where the doping profile satisfies some compatibility conditions. Under natural additional assumptions on the internal energies one gets an differential-algebraic system for the limiting (λ = 0) particle densities, namely the quantum zero-space-charge model. The analysis of the subsequent limit ε → 0 exhibits the importance of quantum gaps. The semiclassical zero-space-charge model is, for small ε, a reasonable approximation of the quantum model if and only if the quantum gap vanishes. The simultaneous limit ε = λ → 0 is analyzed.

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17

Lübben, M., F. Cüppers, J. Mohr, M. von Witzleben, U. Breuer, R. Waser, C. Neumann, and I. Valov. "Design of defect-chemical properties and device performance in memristive systems." Science Advances 6, no. 19 (May 2020): eaaz9079. http://dx.doi.org/10.1126/sciadv.aaz9079.

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Future development of the modern nanoelectronics and its flagships internet of things, artificial intelligence, and neuromorphic computing is largely associated with memristive elements, offering a spectrum of inevitable functionalities, atomic level scalability, and low-power operation. However, their development is limited by significant variability and still phenomenologically orientated materials’ design strategy. Here, we highlight the vital importance of materials’ purity, demonstrating that even parts-per-million foreign elements substantially change performance. Appropriate choice of chemistry and amount of doping element selectively enhances the desired functionality. Dopant/impurity-dependent structure and charge/potential distribution in the space-charge layers and cell capacitance determine the device kinetics and functions. The relation between chemical composition/purity and switching/neuromorphic performance is experimentally evidenced, providing directions for a rational design of future memristive devices.

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18

Paradisi, Andrea, Johan Biscaras, and Abhay Shukla. "Inducing conductivity in polycrystalline ZnO1-x thin films through space charge doping." Journal of Applied Physics 122, no. 9 (September 7, 2017): 095301. http://dx.doi.org/10.1063/1.5001127.

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19

Tian, Xiaoling, Qingyuan Gu, Jiahua Duan, Runkun Chen, Huaping Liu, Yanxue Hou, and Jianing Chen. "Improving Luttinger-liquid plasmons in carbon nanotubes by chemical doping." Nanoscale 10, no. 14 (2018): 6288–93. http://dx.doi.org/10.1039/c8nr00310f.

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20

Yin, Hongxia, Yingcao Cui, Yanhui Wei, Chuncheng Hao, and Qingquan Lei. "Synthesis of a Novel Semi-Conductive Composites Doping with La0.8Sr0.2MnO3 for Excellent Electric Performance for HVDC Cable." Polymers 12, no. 4 (April 4, 2020): 809. http://dx.doi.org/10.3390/polym12040809.

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The semi-conductive layer located between the wire core and the insulation layer in high voltage direct current (HVDC) cable plays a vital role in uniform electric field and affecting space charges behaviors. In this work, the research idea of adding ionic conductive particles to semi-conductive materials to improve the conductive network and reduce the energy of the moving charge inside it and to suppress charge injection was proposed. Semi-conductive composites doped with different La0.8Sr0.2MnO3 (LSM) contents were prepared. Resistivity at different temperatures was measured to investigate the positive temperature coefficient (PTC) effect. Pulse electro-acoustic (PEA) method and thermal-stimulation depolarization currents (TSDC) tests of the insulation layers were carried out. From the results, space charge distribution and TSDC currents in the insulation samples were analyzed to evaluate the inhibitory effect on space charge injection. When LSM content is 6 wt. %, the experimental results show that the PTC effect of the specimen and charge injection are both being suppressed significantly. The maximum resistivity of it is decreased by 53.3% and the insulation sample has the smallest charge amount, 1.85 × 10−7 C under 10 kV/mm—decreased by 40%, 3.6 × 10−7 C under 20 kV/mm—decreased by 45%, and 6.42 × 10−7 C under 30 kV/mm—decreased by 26%. When the LSM content reaches 10 wt. %, the suppression effect on the PTC effect and the charge injection are both weakened, owing to the agglomeration of the conductive particles inside the composites which leads to the interface electric field distortion and results in charge injection enhancement.

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Yu, Guang, and Yujia Cheng. "Effects of Inorganic ZnO Particle Doping on Crystalline Polymer Morphology and Space Charge Behavior." Coatings 10, no. 10 (September 29, 2020): 932. http://dx.doi.org/10.3390/coatings10100932.

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This study further investigated the synergistic effect of micro- and nanofiller doping on matrix material space charges and breakdown characteristics. Accordingly, low-density polyethylene (LDPE) was used as the matrix material, and spherical ZnO particles with sizes of 30 nm and 1 µm were used as additives. Micro-ZnO/LDPE, nano-ZnO/LDPE, and micro-nano-ZnO/LDPE composites were prepared through melt blending. The crystalline morphologies of the composites were observed via polarized light microscopy. The composite crystallinity and melting peak temperature were measured via differential scanning calorimetry, and the micro- and nanoparticle dispersions in the matrix were observed via scanning electron microscopy. The test results showed that the particles were uniformly dispersed in the polyethylene matrix. The filler acted as a heterogeneous nucleation agent in the matrix. The crystal size decreased, thereby increasing the crystal quantity. The doping of inorganic ZnO particles improved the composite crystallinity. The ZnO/LDPE composites were subjected to DC breakdown, space charge, and dielectric spectrum tests. When the crystal arrangement of the sample was loose and its size was large, the breakdown process developed along a shorter path, and the field strength of the composite breakdown decreased. The order of AC and DC breakdown field strengths of the samples was as follows: micro-ZnO/LDPE < pure LDPE < micro-nano-ZnO/LDPE < nano-ZnO/LDPE. The DC and AC breakdown field strengths of the micro- and nano-ZnO/LDPE were 4.7% and 3.2% higher than those of the pure LDPE, respectively. Moreover, the DC and AC breakdown field strengths of the nano-ZnO/LDPE were 11.02% and 15.8% higher than those of the pure LDPE, respectively. The doping of inorganic ZnO particles restrained the space charge accumulation, and the residual charges decreased after short-circuit treatment. The dielectric constant of all nanocomposites was lower than that of LDPE, and the dielectric loss of all composites was higher than that of LDPE.

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ZHU, ZHIEN, YEWEN ZHANG, ZHENLIAN AN, and FEIHU ZHENG. "INVESTIGATION OF SPACE CHARGE TRAP LEVELS IN Al2O3 NANO-POWDER DOPED POLYETHYLENE BY PHOTO-STIMULATED DISCHARGE METHOD." International Journal of Modern Physics B 26, no. 26 (September 11, 2012): 1250140. http://dx.doi.org/10.1142/s0217979212501408.

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The trap levels of Al 2 O 3 nano-powder doped LDPE with different Al 2 O 3 contents are investigated by PSD technique. The variation of trap depth in the doped LDPE can be qualitatively estimated by PSD spectra in continuous scanning method, and the distribution of trap levels in the samples can be quantitatively described in step scanning method. It is indicated that the trap levels of LDPE can be evidently deepened by Al 2 O 3 nano-powder doping with the content more than 0.1 wt%. According to the relative reports on the effect of nano-powder doping to space charge injection, it is considered that the suppression of space charge is probably correlated to the deeper trap levels in Al 2 O 3 nano-powder doped LDPE.

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23

Wang, Yani, Shuai Zhang, Yuanyuan Sun, Xingwu Yang, and Chun Liu. "Effect of Nano-MgO Doping in XLPE on Charge Transport and Electric Field Distribution in Composite Insulation of HVDC Cable Joint." Energies 15, no. 19 (September 22, 2022): 6948. http://dx.doi.org/10.3390/en15196948.

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The space charge characteristics of cross-linked polyethylene (XLPE) can be improved to some extent by doping the appropriate amount of nano-MgO. In this study, in order to explore the influence of nano-MgO on the space charge and electric field distributions of the composite insulation of high voltage direct current (HVDC) cable joints, the effect of nano-MgO concentration on the depth and density of the deep traps in MgO/XLPE was first analyzed. On this basis, the charge transport simulation model of a 320 kV HVDC cable joint was established with MgO/XLPE as the cable insulation, and the space charge and electric field distributions of the cable joint under different temperature conditions were simulated. It was found that the radial charge distribution in the joint shows different trends with the change of nano-MgO concentration. There is a significant difference in the charge density on both sides of the (MgO/XLPE)/EPDM interface, and the difference first decreased and then increased with the increase of concentration. When the nano-MgO concentration was 0.5 wt%, the number of charges in the radial direction is the fewest, and the maximum value is only 0.42 C/m−3. The radial electric field changed abruptly at the (MgO/XLPE)/EPDM interface, and it was homogenized to a certain extent with time. It was found that the highest electric field of the interface is at the root of the stress cone, which is the weakest point of the joint insulation. When the nano-MgO concentration was 0.5 wt%, the electric field at the root of the stress cone was found to be the lowest, with a value of 13.38 kV/mm. A comprehensive comparison shows that the joint can maintain better insulation when the concentration is 0.5 wt% compared to other concentrations. The results can provide a basis for further improving the insulation properties of HVDC cable joints through nano doping technology.

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Surdi, Harshad, Trevor Thornton, Robert J. Nemanich, and Stephen M. Goodnick. "Space charge limited corrections to the power figure of merit for diamond." Applied Physics Letters 120, no. 22 (May 30, 2022): 223503. http://dx.doi.org/10.1063/5.0087059.

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An interpretation of the unipolar figure of merit is formulated for wide bandgap (WBG) semiconductors based on the on-state specific resistance ([Formula: see text]) derived from the space charge limited current–voltage relationship (Mott–Gurney square law). The limitations of the traditional Ohmic [Formula: see text] for WBG semiconductors are discussed, particularly at low doping, while the accuracy of the Mott–Gurney based [Formula: see text] is confirmed by Silvaco ATLAS drift–diffusion simulations of diamond Schottky pin diodes. The effects of incomplete ionization are considered as well.

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25

Chen, Inan. "Theoretical analyses of space-charge doping in amorphous semiconductor superlattices. II. Compositional superlattices." Physical Review B 32, no. 2 (July 15, 1985): 885–89. http://dx.doi.org/10.1103/physrevb.32.885.

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26

Mesaros, Andrej, Kazuhiro Fujita, Stephen D. Edkins, Mohammad H. Hamidian, Hiroshi Eisaki, Shin-ichi Uchida, J. C. Séamus Davis, Michael J. Lawler, and Eun-Ah Kim. "Commensurate 4a0-period charge density modulations throughout the Bi2Sr2CaCu2O8+x pseudogap regime." Proceedings of the National Academy of Sciences 113, no. 45 (October 20, 2016): 12661–66. http://dx.doi.org/10.1073/pnas.1614247113.

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Theories based upon strong real space (r-space) electron–electron interactions have long predicted that unidirectional charge density modulations (CDMs) with four-unit-cell (4a0) periodicity should occur in the hole-doped cuprate Mott insulator (MI). Experimentally, however, increasing the hole density p is reported to cause the conventionally defined wavevector QA of the CDM to evolve continuously as if driven primarily by momentum-space (k-space) effects. Here we introduce phase-resolved electronic structure visualization for determination of the cuprate CDM wavevector. Remarkably, this technique reveals a virtually doping-independent locking of the local CDM wavevector at |Q0|=2π/4a0 throughout the underdoped phase diagram of the canonical cuprate Bi2Sr2CaCu2O8. These observations have significant fundamental consequences because they are orthogonal to a k-space (Fermi-surface)–based picture of the cuprate CDMs but are consistent with strong-coupling r-space–based theories. Our findings imply that it is the latter that provides the intrinsic organizational principle for the cuprate CDM state.

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Bochkova, T. M., and S. N. Plyaka. "I─V characteristics of Bi4Ge3O12─Mn crystals in the unipolar injection mode." Journal of Physics and Electronics 27, no. 2 (December 27, 2019): 81–84. http://dx.doi.org/10.15421/331929.

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Current-voltage relations in Bi4Ge3O12 ─ Mn crystals were measured under the conditions of unipolar injection of charge carriers. The characteristics obtained for electrons and holes are different. I-V curves in the case of electron injection contain ohmic, quadratic regions and regions of a sharp increase in current. This indicates the formation of a space charge enriched in electrons. The values of conductivity, effective drift mobility, and electron concentration calculated at different temperatures are close to the values obtained for pure crystals. In the case of hole injection I-V curves are characterized by the presence of sublinear regions. It is assumed that injection of the holes causes the formation of a space charge layer depleted in electrons due to the recombination. It is shown that doping with manganese does not change the nature of conductivity in bismuth germanate crystals and strongly affects the recombination processes.

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Zhou, Yansong, Gang Chen, Yaoguang Yu, Lichen Zhao, Qilin Yu, and Qiang He. "Effects of La-doping on charge separation behavior of ZnO:GaN for its enhanced photocatalytic performance." Catalysis Science & Technology 6, no. 4 (2016): 1033–41. http://dx.doi.org/10.1039/c5cy01193k.

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In this work, lanthanum (La) has been proven as an effective space charge layer modifier to promote efficient photogenerated charge carrier separation for ZnO:GaN solid solution photocatalysts with enhanced photocatalytic water-splitting performance.

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Bebitov, Rakhim, Oybek Abdulkhaev, Dilbara Yodgorova, Damir Istamov, Giyos Khamdamov, Shukurullo Kuliyev, J. Sh Abdullaev, Alim Khakimov, and Akhmad Rakhmatov. "Potential distribution over temperature sensors of p-n junction diodes with arbitrary doping of the base region." E3S Web of Conferences 401 (2023): 03062. http://dx.doi.org/10.1051/e3sconf/202340103062.

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In p-n-junction temperature sensors connected in the forwardbiased, the temperature dependence of the built-in potential is important, while in the reverse biased p-n-junction temperature sensors, it is necessary to study the temperature dependence of the built-in potential and space-charge region width.For this case, as well as for homogeneous and gradient alloyed cases, the temperature dependence of built-in potential and space-charge region widthare studied and mathematical analysis is presented for these cases.Based on these mathematical analysis, the results are obtained for cases where the base region of p-n-junction temperature sensors is doped at different concentrations with a homogeneous or inhomogeneous distributions of impurities. It is well known that in conventional temperature sensors, when the main current transport mechanism is determined by generation-recombination processes in space charge region, the dependence of the space charge region width on the temperature can affect the linearity of temperature response curve of sensor, it is desirable to increase the doping rate of the base region to weaken this effect, or it is necessary to use p-n junction.

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Dong, Jinou, Xueqin Zhao, Licheng Fu, Yilun Gu, Rufei Zhang, Qiaolin Yang, Lingfeng Xie, and Fanlong Ning. "(Ca,K)(Zn,Mn)₂As₂: Ferromagnetic semiconductor induced by decoupled charge and spin doping in CaZn₂As₂." Journal of Semiconductors 43, no. 7 (July 1, 2022): 072501. http://dx.doi.org/10.1088/1674-4926/43/7/072501.

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Abstract We have successfully synthesized a novel diluted magnetic semiconductor (Ca1−2x K2x )(Zn1− x Mn x )2As2 with decoupled charge and spin doping. The substitutions of (Ca2+, K+) and (Zn2+, Mn2+) in the parent compound CaZn2As2 (space group P m1 (No. 164)) introduce carriers and magnetic moments, respectively. Doping only Mn into CaZn2As2 does not induce any type of long range magnetic ordering. The ferromagnetic ordering arise can only when K+ and Mn2+ are simultaneously doped. The resulted maximum Curie temperature reaches ~7 K, and the corresponding coercive field is ~60 Oe. The transport measurements confirm that samples with K and Mn co-doping still behave like a semiconductor.

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31

Paradisi, Andrea, Johan Biscaras, and Abhay Shukla. "Space charge induced electrostatic doping of two-dimensional materials: Graphene as a case study." Applied Physics Letters 107, no. 14 (October 5, 2015): 143103. http://dx.doi.org/10.1063/1.4932572.

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32

Engel, Jesse H., and A. Paul Alivisatos. "Postsynthetic Doping Control of Nanocrystal Thin Films: Balancing Space Charge to Improve Photovoltaic Efficiency." Chemistry of Materials 26, no. 1 (September 18, 2013): 153–62. http://dx.doi.org/10.1021/cm402383r.

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33

Banerjee, Sreyasi, and Basudev Ghosh. "Effect of doping on amplitude modulation of space-charge wave in semiconductor quantum plasma." Indian Journal of Physics 91, no. 4 (December 2, 2016): 461–69. http://dx.doi.org/10.1007/s12648-016-0939-1.

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34

Szalbot, Diana, Małgorzata Adamczyk, Beata Wodecka-Duś, Jolanta Dzik, Michał Rerak, and Kamil Feliksik. "Influence of calcium doping on microstructure, dielectric and electric properties of BaBi2Nb2O9 ceramics." Processing and Application of Ceramics 12, no. 2 (2018): 171–79. http://dx.doi.org/10.2298/pac1802171s.

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Barium bismuth niobiate (BaBi2Nb2O9) ceramics modified by calcium were prepared by solid state synthesis and two-step sintering process. An impact of calcium substitution on the A site of perovskite block is presented. The investigations are focused on dielectric as well as electric aspects of the modification. The presented results reveal that the concentration of a space charge is not preserved, what is surprising due to the homovalent nature of the dopant and no reason for creating additional lattice defects and charges connected. However, not only the valence of ions, but also the calcium-oxygen and barium-oxygen bond strength should be taken into consideration. Since the calcium-oxygen bond is probably weaker the loss of the bismuth oxide is expected to increase with an increase in the calcium content. Such a scenario results in appearance of a large number of negative charge carriers connected with unsaturated oxygen ions.

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35

Lee, Hsin-Ying, and Hung-Lin Huang. "Investigation Performance and Mechanisms of Inverted Polymer Solar Cells by Pentacene Doped P3HT : PCBM." International Journal of Photoenergy 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/812643.

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The inverted polymer solar cells (PSCs) with pentacene-doped P3HT : PCBM absorption layers were fabricated. It was demonstrated that the pentacene doping modulated the electron mobility and the hole mobility in the resulting absorption layer. Furthermore, by varying the doping content, the optimal carrier mobility balance could be obtained. In addition, the pentacene doping led to an improvement in the crystallinity of the resulting films and made an enhancement in the light absorption, which was partly responsible for the performance improvement of the solar cells. Using the space-charge-limited current (SCLC) method, it was determined that the balanced carrier mobility (μh/μe=1.000) was nearly achieved when a pentacene doping ratio of 0.065 by weight was doped into the P3HT : PCBM : pentacene absorption layer. Compared with the inverted PSCs without the pentacene doping, the short circuit current density and the power conversion efficiency of the inverted PSCs with the pentacene doping ratio of 0.065 were increased from 9.73 mA/cm2to 11.26 mA/cm2and from 3.39% to 4.31%, respectively.

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36

Shah, M. A. K. Yousaf, Yuzheng Lu, Naveed Mushtaq, Muhammad Yousaf, and Bin Zhu. "Unraveling the synergistic effect on ionic transport of ceria via the surface engineering for low-temperature ceramic fuel cells." Applied Physics Letters 122, no. 11 (March 13, 2023): 113902. http://dx.doi.org/10.1063/5.0137303.

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Recently, the multifunctional semiconductor CeO2 realized high ionic conductivity via surface conduction and delivered higher fuel cell performance. This indicates a promising strategy for the design of an electrolyte for the low-temperature ceramic fuel cell. In this study, we develop a ceria-based electrolyte by surface doping Bi into CeO2 to attain the CeBiO2 (BDC) electrolyte. The designed electrolyte is facilitated with an enriched O-vacancy surface layer, enabling high ionic conduction (0.20 S/cm) and excellent power density (1057 mW/cm2) at 530 °C. The difference in the Fermi level of BDC and CeO2 arises due to the surface doping, which entails the band alignment and establishes the space charge region, thereby constituting a built-in field enhancing the charge transportation and minimizing e-conduction. In order to assist the formation of O-vacancies in the design, the BDC electrolyte density functional theory calculation was also made. These findings suggest surface doping is the best approach to attaining excellent performance and designing electrolytes and electrodes for advanced low-temperature fuel cell technology.

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37

Wang, Youyuan, Yudong Li, Zhanxi Zhang, and Yanfang Zhang. "Effect of Doping Microcapsules on Typical Electrical Performances of Self-Healing Polyethylene Insulating Composite." Applied Sciences 9, no. 15 (July 27, 2019): 3039. http://dx.doi.org/10.3390/app9153039.

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Polyethylene cables, as important transmission equipment of modern power grid, would inevitably be slightly damaged, which seriously threatens the safety of the power supply. This paper has pioneered the preparation and typical performances of a self-healing polyethylene insulating composite. The self-healing performance to structural damage was verified by tests of electrical and mechanical damage. The effect mechanism of doping microcapsules on the electrical performance of polyethylene was emphatically analyzed. The results show that in appropriate conditions (such as 60 °C/30 min), the composite can not only repair the electrical tree and scratches, but also restore the insulation strength of damaged area. The effect of doping microcapsules on the electrical performances of polyethylene, such as breakdown strength, volumetric resistivity, dielectric properties, and space charge characteristics, are mainly related to impurity and the interface of microcapsule. Polarization and ionization of impurities can reduce the electrical performance of polyethylene. The interface not only improves the microstructure of polyethylene (such as how the heterogeneous nucleation effect increases the number of crystal regions, and the anchoring effect enhances the stability of amorphous regions), but also increases the charge traps. Moreover, the microstructure and charge trap can affect the characteristics of carrier transport, material polarization, and space charge accumulation, thus improving the electrical performance of polyethylene. In addition, the important electrical performance of the composite can meet the basic application requirements of polyethylene insulating material, which has good application prospects.

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Turkulets, Yury, and Ilan Shalish. "Franz-Keldysh effect in semiconductor built-in fields: Doping concentration and space charge region characterization." Journal of Applied Physics 124, no. 7 (August 21, 2018): 075102. http://dx.doi.org/10.1063/1.5038800.

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Liou, J. J., and F. A. Lindholm. "Low‐temperaturep‐njunction space‐charge‐region thickness including the effects of doping‐dependent dielectric permittivity." Journal of Applied Physics 64, no. 11 (December 1988): 6369–72. http://dx.doi.org/10.1063/1.342072.

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40

Fuks, B. I. "Theory of slow traps and random telegraph signals in ultra-small planar MOSFETs." AIP Advances 13, no. 3 (March 1, 2023): 035029. http://dx.doi.org/10.1063/5.0135226.

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It is shown that ultra-small MOSFETs with heavily doped substrates contain a significant concentration of slow traps in their space-charge regions. Such a trap arises due to random doping fluctuations and is created if a few shallow impurities form a small-scale cluster, resulting in a high binding energy of the ground state of the particle on this multiply charged “nucleus.” Inside the space-charge region, this “nucleus” is surrounded by a high potential barrier, which turns it into a slow trap with capture and emission times not too different from each other. Since a multiply charged trap scatters free carriers much more than a singly charged trap, it generates an easily observable random telegraph signal (RTS) when it captures or emits a free carrier. Such traps, located near the silicon–dielectric interface, generate high-amplitude RTSs that interfere with the normal operation of ultra-small MOSFETs. The probability of their formation depends very sharply on the doping profile near the interface. Therefore, if it can be proven that the slow traps generating the observed RTSs are in silicon, this will provide a clue to reducing this probability. This paper develops a theory describing why a multiply charged silicon slow trap can generate a high-amplitude random telegraph signal, how to reliably distinguish whether the observed RTS is generated by a silicon or oxide trap, and what experimental data are required for this. An analysis of the relevant published data for the RTSs observed in such a MOSFET shows that they are generated by slow traps located in silicon rather than in oxide. The developed theory is in qualitative and reasonable quantitative agreement with the analyzed data.

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41

Katsufuji, T., Y. Tokura, T. Ido, and S. Uchida. "Symmetry-dependent electronic Raman scattering inLa2−xSrxCuO4: Evidence for doping-induced change in thek-space anisotropy of charge dynamics." Physical Review B 48, no. 21 (December 1, 1993): 16131–34. http://dx.doi.org/10.1103/physrevb.48.16131.

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42

Verma, Deepa, Armelle Michau, Angela Vasanelli, Carlo Sirtori, and Khaled Hassouni. "Terahertz emission from a bounded plasma." Physics of Plasmas 30, no. 1 (January 2023): 013507. http://dx.doi.org/10.1063/5.0116748.

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The dynamics of electrons submitted to voltage pulses in a thin semiconductor layer is investigated using a kinetic approach based on the solution of the electron Boltzmann equation using particle-in-cell/Monte Carlo collision simulations. The results showed that due to the fairly high plasma density, oscillations emerge from a highly nonlinear interaction between the space-charge field and the electrons. The voltage pulse excites electron waves with dynamics and phase-space trajectories that depend on the doping level. High-amplitude oscillations take place during the relaxation phase and are subsequently damped over time-scales in the range 100 –400 fs and decrease with the doping level. The power spectra of these oscillations show a high-energy band and a low-energy peak that were attributed to bounded plasma resonances and to a sheath effect. The high-energy THz domain reduces to sharp and well-defined peaks for the high doping case. The radiative power that would be emitted by the thin semiconductor layer strongly depends on the competition between damping and radiative decay in the electron dynamics. Simulations showed that higher doping level favor enhanced magnitude and much slower damping for the high-frequency current, which would strongly enhance the emitted level of THz radiation.

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43

Yu, Guang, Yujia Cheng, and Xiaohong Zhang. "The Dielectric Properties Improvement of Cable Insulation Layer by Different Morphology Nanoparticles Doping into LDPE." Coatings 9, no. 3 (March 21, 2019): 204. http://dx.doi.org/10.3390/coatings9030204.

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Low density polyethylene (LDPE) doped with inorganic nano-MMT and nano-ZnO particles improved the dielectric properties of the cable insulation layer. In this article, nano-MMT/LDPE and nano-ZnO/LDPE composites were prepared by polymer intercalation and melt blending, respectively. The octadecyl quaternary ammonium salt and silane coupling agent were applied for surface modification in nano-MMT and nano-ZnO particles, and this then improved the compatibility of nanoparticles and polymeric matrix. These samples were characterized by FTIR, PLM, DSC and TSC, from which the effect of nanoparticles doping on polymer crystal habit and interface traps would be explored. In these experiments, the AC breakdown characteristics and space charge characteristic of different composites were studied. The experimental results showed that the interface bonding of nanoparticles and polymer was improved by coupling agents modifying. The dispersion of nanoparticles in matrix was better. When the mass fraction of nanoparticles doping was 3 wt.%, the crystallization rate and crystallinity of composites increased, and the crystalline structure was more complete. Besides, the amorphous regions in material decreased and the conducting channel was circuitous. At this time, the breakdown field strength of nano-MMT/LDPE and nano-ZnO/LDPE increased by 10.3% and 11.1%, compared to that of pure LDPE, respectively. Furthermore, the density and depth of interface traps in polymer increased with nanoparticles doping. Nano-MMT and nano-ZnO could both restrain the space charge accumulation, and the inhibiting effect of nano-ZnO was more visible.

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Guo, Ning, Ruixiao Meng, Junguo Gao, Mingpeng He, Yue Zhang, Lizhi He, and Haitao Hu. "Properties and Simulating Research of Epoxy Resin/Micron-SiC/Nano-SiO2 Composite." Energies 15, no. 13 (July 1, 2022): 4821. http://dx.doi.org/10.3390/en15134821.

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The dielectric behavior of insulations is a key factor affecting the development of anti-corona materials for generators. Epoxy resin (EP), as the matrix, is blended with inorganic fillers of micron SiC and nano SiO2 to investigate the effect of micro and nano doping on the conductivity and breakdown mechanism of the composites. Using experimental and simulation analysis, it is found that the effect of nano-SiO2 doping concentration on the conductivity is related to the dispersion of SiC particles. The lower concentration of SiO2 could decrease the conductivity of the composites. The conductivity increases with raising the nano-SiO2 doping concentration to a critical value. Meanwhile, the breakdown field strength of the composites decreases with the rising content of SiC in constant SiO2 and increases with more SiO2 when mixed with invariable SiC. When an equivalent electric field is applied to the samples, the electric field at the interface of micron particles is much stronger than the average field of the dielectric, close to the critical electric field of the tunneling effect. The density of the homopolar space charge bound to the surface of the stator bar elevates as the concentration of filled nanoparticles increases, by which a more effective Coulomb potential shield can be built to inhibit the further injection of carriers from the electrode to the interior of the anti-corona layer, thus reducing the space charge accumulation in the anti-corona layer as well as increasing the breakdown field strength of the dielectric.

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45

Jiang, Hongtao, Xiaohong Zhang, Junguo Gao, and Ning Guo. "Conductance Current and Space Charge Characteristics of SiO2/MMT/LDPE Micro-Nano Composites." Materials 13, no. 18 (September 16, 2020): 4119. http://dx.doi.org/10.3390/ma13184119.

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Low-density polyethylene (LDPE) is one of the most comprehensive products used as insulation materials in power equipment. How to improve its dielectric properties by doping inorganic particles in LDPE has always been the focus of many researchers. In this paper, silica (SiO2) particles and montmorillonite (MMT) particles were added to LDPE, the order of adding particles was changed, and different micro-nano composites was made. The crystallization characteristics of composites were analyzed, the curves of the conductance current with the change of field intensity were analyzed, and the space charge distribution of each material were investigated. The results of crystallization show that the crystalline properties and crystallinity of the composites are higher than the matrix LDPE, the addition of SiO2 particles increases the composites’ crystallinity significantly, and the intercellular spacing of micro-nano composites is the smallest among all materials. The curve of conductance current versus electric field intensity shows that the tightness of the crystal structure can effectively hinder the movement of the molecular chain, inhibit carrier migration, while shortening the free travel of electrons, thereby reducing the electric conduction current of the material. The experimental results of the space charge accumulation curve further show that the compact crystal structure of the material is beneficial to the dissipation of space charge in the dielectric.

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Keeratithiwakorn, Poonnapa, Korakot Onlaor, T. Thiwawong, and B. Tunhoo. "Impedance Spectroscopy Studies of DCM Doped Alq₃ Organic Material." Advanced Materials Research 802 (September 2013): 59–63. http://dx.doi.org/10.4028/www.scientific.net/amr.802.59.

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In this work, we report on the frequency-impedance characteristics of dye-doped organic material. The device structure is glass substrate/indium tin oxide/DCM:Alq3/Aluminum 100 nm. The influence of doping concentraion has been investigated by impedance spectroscopy. The impedance characteristics of the dye-doped organic material can be modelled by simply adopting the conventional equivalent circuit with the simple combination of resistors and capacitor network. The variation of bulk resistance with applied bias voltage as a result of the Space Charge Limited Conduction (SCLC) mechanism for charge conduction.

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47

WANG, SHU. "QUASINEUTRAL LIMIT OF THE MULTI-DIMENSIONAL DRIFT-DIFFUSION-POISSON MODELS FOR SEMICONDUCTORS WITH PN-JUNCTIONS." Mathematical Models and Methods in Applied Sciences 16, no. 04 (April 2006): 537–57. http://dx.doi.org/10.1142/s021820250600125x.

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In this paper the vanishing Debye length limit (space charge neutral limit) of bipolar time-dependent drift-diffusion models for semiconductors with p-n-junctions (i.e. with a fixed bipolar background charge) is studied in the multi-dimensional case. For generally smooth sign-changing doping profiles with good boundary conditions, the quasineutral limit (zero-Debye-length limit) is justified rigorously in the Sobolev's norm uniformly in time. The proof is based on the elaborate energy method and the relative entropy functional method which yields the uniform estimates with respect to the scaled Debye length.

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48

Engel, Jesse H., and A. Paul Alivisatos. "ChemInform Abstract: Postsynthetic Doping Control of Nanocrystal Thin Films: Balancing Space Charge to Improve Photovoltaic Efficiency." ChemInform 45, no. 9 (February 14, 2014): no. http://dx.doi.org/10.1002/chin.201409236.

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Hashem, Abdel-Ghany, Scheuermann, Indris, Ehrenberg, Mauger, and Julien. "Doped Nanoscale NMC333 as Cathode Materials for Li-Ion Batteries." Materials 12, no. 18 (September 7, 2019): 2899. http://dx.doi.org/10.3390/ma12182899.

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A series of Li(Ni1/3Mn1/3Co1/3)1−xMxO2 (M = Al, Mg, Zn, and Fe, x = 0.06) was prepared via sol-gel method assisted by ethylene diamine tetra acetic acid as a chelating agent. A typical hexagonal α-NaFeO2 structure (R-3m space group) was observed for parent and doped samples as revealed by X-ray diffraction patterns. For all samples, hexagonally shaped nanoparticles were observed by scanning electron microscopy and transmission electron microscopy. The local structure was characterized by infrared, Raman, and Mössbauer spectroscopy and 7Li nuclear magnetic resonance (Li-NMR). Cyclic voltammetry and galvanostatic charge-discharge tests showed that Mg and Al doping improved the electrochemical performance of LiNi1/3Mn1/3Co1/3O2 in terms of specific capacities and cyclability. In addition, while Al doping increases the initial capacity, Mg doping is the best choice as it improves cyclability for reasons discussed in this work.

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Kienzle, O., F. Ernst, and Manfred Rühle. "Structure And Composition Of Grain Boundaries In SrTiO3." Microscopy and Microanalysis 5, S2 (August 1999): 94–95. http://dx.doi.org/10.1017/s1431927600013799.

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The electrical properties of SrTiO3 (strontium titanate) ceramics are strongly influenced or even dictated by grain boundary segregation of charged point defects, such as dopant atoms, impurities, vacancies, or self-interstitials. The atomistic structure of the grain boundaries, their energy, and the segregation of point defects mutually depend on each other. Grain boundary segregation of charged point defects induces the formation of space charge layers in the adjoining crystals. In order to investigate the relation between grain boundary structure and composition, grain boundaries in Fedoped SrTiO3 bicrystals and in SrTiO3 ceramics were studied by HRTEM and by AEM with subnanometer resolution.Quantitative HRTEM served to investigate the atomistic structure of Σ=3, (111) grain boundaries in Fe-doped SrTiO3 bicrystals with a doping level of Fe/Ti= 0.04at% (Fig. 1). Analysis of the translation state revealed that the Σ=3, (111) grain boundary has an excess volume: normal to the boundary plane, the spacing between the two crystals exceeds what one would expect from a coincidence site lattice model by (0.06 ±0.01 )nm.

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Journal articles on the topic 'Space charge doping'

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