Journal articles: 'Poole-Frenkel-Transport'

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Girolami, M., A. Bellucci, P. Calvani, R. Flammini, and D. M. Trucchi. "Radiation-assisted Frenkel-Poole transport in single-crystal diamond." Applied Physics Letters 103, no. 8 (August 19, 2013): 083502. http://dx.doi.org/10.1063/1.4818904.

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Lenz, Thomas, Moses Richter, Gebhard J. Matt, Norman A. Luechinger, Samuel C. Halim, Wolfgang Heiss, and Christoph J. Brabec. "Charge transport in nanoparticular thin films of zinc oxide and aluminum-doped zinc oxide." Journal of Materials Chemistry C 3, no. 7 (2015): 1468–72. http://dx.doi.org/10.1039/c4tc01969e.

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In this work, we report on the electrical characterization of nanoparticular thin films of zinc oxide and aluminum-doped ZnO. Temperature-dependent current–voltage measurements revealed that charge transport is well described by the Poole–Frenkel model.

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Acharya, Sanchar, Binita Tongbram, Indradev S. Samajdar, and Anil Kottantharayil. "What causes Poole-Frenkel transport in VLS grown silicon nanowires?" Materials Science in Semiconductor Processing 105 (January 2020): 104749. http://dx.doi.org/10.1016/j.mssp.2019.104749.

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Acharya, Sanchar, and Anil Kottantharayil. "Poole–Frenkel Transport in Gold Catalyzed VLS Grown Silicon Nanowires." IEEE Transactions on Electron Devices 65, no. 5 (May 2018): 1685–91. http://dx.doi.org/10.1109/ted.2018.2817544.

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CHOHAN, M. H., A. H. KHALID, M. ZULFIQAR, P. K. BUTT, FARAH KHAN, and RIZWAN HUSSAIN. "ELECTRON TRANSPORT MECHANISM IN COBALT POLYMETHACRYLATE (CoPMA)." Modern Physics Letters B 05, no. 29 (December 20, 1991): 1933–38. http://dx.doi.org/10.1142/s021798499100232x.

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Electron transport mechanisms in cobalt polymethacrylate have been investigated. The electrical measurements made on the polymer, show that the current-voltage relationship at lower voltages (V<300 V) is ohmic whereas at higher voltages it is exponential. The strong temperature dependence of current on voltage indicates the dominance of a Poole-Frenkel mechanism and the existence of trapping levels. Low activation energy values suggest an electronic conduction mechanism.

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Schwarz, R., J. J. Sun, R. Rocha, E. Morgado, and Paulo Freitas. "Transition from Tunneling to Poole-Frenkel Type Transport in Aluminum-Nitride." Materials Science Forum 258-263 (December 1997): 1259–64. http://dx.doi.org/10.4028/www.scientific.net/msf.258-263.1259.

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Betti Beneventi, Giovanni, Lucrezia Guarino, Massimo Ferro, and Paolo Fantini. "Three-dimensional Poole-Frenkel analytical model for carrier transport in amorphous chalcogenides." Journal of Applied Physics 113, no. 4 (January 28, 2013): 044506. http://dx.doi.org/10.1063/1.4788798.

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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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Choueib, M., A. Ayari, P. Vincent, S. Perisanu, and S. T. Purcell. "Evidence for Poole–Frenkel conduction in individual SiC nanowires by field emission transport measurements." Journal of Applied Physics 109, no. 7 (April 2011): 073709. http://dx.doi.org/10.1063/1.3556736.

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Kim, Hog Young, Ahrum Sohn, and Dong Wook Kim. "Temperature-Dependent Current-Voltage Characteristics in ZnO Based Schottky Diodes." Advanced Materials Research 894 (February 2014): 391–95. http://dx.doi.org/10.4028/www.scientific.net/amr.894.391.

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Using currentvoltage (IV) measurements, the temperature-dependent current transport in Ag/Zn-polar ZnO Schottky diodes was investigated. Both the series and shunt resistances of the diode were altered at the different temperatures, which were related to the amount of free carriers and the formation of a vacuum-activated surface conduction path, respectively. The reverse biased current transport was associated with a thermally assisted tunneling field emission of carriers and the Poole-Frenkel effect, for higher and lower voltages, respectively. The average interface state density decreased with increasing temperature, which was due to a result of molecular restructuring and reordering and/or variation of the ideality factor with temperatures across the Ag/ZnO interface.

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Zhao, Xin-Dong, Hong Zhao, and Wei-Feng Sun. "Significantly Improved Electrical Properties of Crosslinked Polyethylene Modified by UV-Initiated Grafting MAH." Polymers 12, no. 1 (January 1, 2020): 62. http://dx.doi.org/10.3390/polym12010062.

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Direct current (DC) electrical performances of crosslinked polyethylene (XLPE) have been evidently improved by developing graft modification technique with ultraviolet (UV) photon-initiation. Maleic anhydride (MAH) molecules with characteristic cyclic anhydride were successfully grafted to polyethylene molecules under UV irradiation, which can be efficiently realized in industrial cable production. The complying laws of electrical current varying with electric field and the Weibull statistics of dielectric breakdown strength at altered temperature for cable operation were analyzed to study the underlying mechanism of improving electrical insulation performances. Compared with pure XLPE, the appreciably decreased electrical conductivity and enhanced breakdown strength were achieved in XLPE-graft-MAH. The critical electric fields of the electrical conduction altering from ohm conductance to trap-limited mechanism significantly decrease with the increased testing temperature, which, however, can be remarkably raised by grafting MAH. At elevated temperatures, the dominant carrier transport mechanism of pure XLPE alters from Poole–Frenkel effect to Schottky injection, while and XLPE-graft-MAH materials persist in the electrical conductance dominated by Poole–Frenkel effect. The polar group of grafted MAH renders deep traps for charge carriers in XLPE-graft-MAH, and accordingly elevate the charge injection barrier and reduce charge mobility, resulting in the suppression of DC electrical conductance and the remarkable amelioration of insulation strength. The well agreement of experimental results with the quantum mechanics calculations suggests a prospective strategy of UV initiation for polar-molecule-grafting modification in the development of high-voltage DC cable materials.

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Novikov, S. V., and A. V. Vannikov. "Charge Carrier Transport in Nonpolar Disordered Organic Materials: What is the Reason for Poole-Frenkel Behavior?" Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals 361, no. 1 (May 2001): 89–94. http://dx.doi.org/10.1080/10587250108025723.

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Gorduk, Semih, Ozge Koyun, Oguzhan Avciata, Ahmet Altindal, and Ulvi Avciata. "Synthesis of Peripherally Tetrasubstituted Phthalocyanines and Their Applications in Schottky Barrier Diodes." Journal of Chemistry 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/9715069.

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New metal-free and metallophthalocyanine compounds (Zn, Co, Ni, and Cu) were synthesized using 2-hydroxymethyl-1,4-benzodioxan and 4-nitrophthalonitrile compounds. All newly synthesized compounds were characterized by elemental analysis, FT-IR, UV-Vis, 1H-NMR, MALDI-TOF MS, and GC-MS techniques. The applications of synthesized compounds in Schottky barrier diodes were investigated. Ag/Pc/p–Si structures were fabricated and charge transport mechanism in these devices was investigated using dc technique. It was observed from the analysis of the experimental results that the charge transport can be described by Ohmic conduction at low values of the reverse bias. On the other hand, the voltage dependence of the measured current for high values of the applied reverse bias indicated that space charge limited conduction is the dominant mechanism responsible for dc conduction. From the observed voltage dependence of the current density under forward bias conditions, it has been concluded that the charge transport is dominated by Poole-Frenkel emission.

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Pautmeier, L., R. Richert, and H. Bässler. "Poole-Frenkel behavior of charge transport in organic solids with off-diagonal disorder studied by Monte Carlo simulation." Synthetic Metals 37, no. 1-3 (August 1990): 271–81. http://dx.doi.org/10.1016/0379-6779(90)90158-h.

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Солован, М. Н., Г. О. Андрущак, А. И. Мостовой, Т. Т. Ковалюк, В. В. Брус, and П. Д. Марьянчук. "Диоды Шоттки графит/p-SiC, полученные методом переноса нарисованной пленки графита на SiC." Физика и техника полупроводников 52, no. 2 (2018): 248. http://dx.doi.org/10.21883/ftp.2018.02.45451.8603.

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AbstractGraphite/ p -SiC Schottky diodes are fabricated using the recently suggested technique of transferring drawn graphite films onto p -SiC single-crystal substrates. The current–voltage and capacitance–voltage characteristics are measured at different temperatures and at different frequencies of a small-signal AC signal, respectively. The temperature dependences of the potential-barrier height and of the series resistance of the graphite/ p -SiC junctions are measured and analyzed. The dominant mechanisms of the charge–carrier transport through the diodes are determined. It is shown that the dominant mechanisms of the transport of charge carriers through the graphite/ p -Si Schottky diodes at a forward bias are multi-step tunneling recombination and tunneling described by the Newman formula (at high bias voltages). At reverse biases, the dominant mechanisms of charge transport are the Frenkel–Poole emission and tunneling. It is shown that the graphite/ p -SiC Schottky diodes can be used as detectors of ultraviolet radiation since they have the open-circuit voltage V _oc = 1.84 V and the short-circuit current density I _sc = 2.9 mA/cm^2 under illumination from a DRL 250-3 mercury–quartz lamp located 3 cm from the sample.

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LIU, JING, and HAI-BO ZHANG. "SELF-CONSIST CHARGING PROCESS OF POLYMER IRRADIATED BY INTERMEDIATE-ENERGY ELECTRON BEAM." Surface Review and Letters 21, no. 05 (September 29, 2014): 1450062. http://dx.doi.org/10.1142/s0218625x14500620.

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This paper reports on the electron scattering, charge transport and charge trapping of a polymer subjected to intermediate-energy electron beam in a self-consist charging model. Numerical simulation of a charging balance is performed using incident intermediate-energy electron current and leakage current, and the space charging characteristics are examined. The mechanisms involve various microscopic parameters that are related to the space potential and the characteristics of the polymer as well as to the effects of the space charge, electron charge, hole charge and trapped charge itself. The dynamic transporting and trapping properties of a polymer are investigated, and the space potential is evaluated using various parameters of irradiation. Trapping of electrons is determined using Poole–Frenkel trapping–detrapping mechanisms. Various types of space charging behavior are observed by controlling irradiation conditions. Furthermore, the peak location of space charge is simulated and validated by Sessler's experimental data in microscopic perspective.

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Jabbari, I., M. Baira, H. Maaref, and R. Mghaieth. "Evidence of Poole-frenkel and Fowler-Nordheim tunneling transport mechanisms in leakage current of (Pd/Au)/Al0.22Ga0.78N/GaN heterostructures." Solid State Communications 314-315 (July 2020): 113920. http://dx.doi.org/10.1016/j.ssc.2020.113920.

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Lean, Meng H., and Wei-Ping L. Chu. "Model for Charge Transport in Ferroelectric Nanocomposite Film." Journal of Polymers 2015 (March 23, 2015): 1–17. http://dx.doi.org/10.1155/2015/745056.

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This paper describes 3D particle-in-cell simulation of charge injection and transport through nanocomposite film comprised of ferroelectric ceramic nanofillers in an amorphous polymer matrix and/or semicrystalline ferroelectric polymer with varying degrees of crystallinity. The classical electrical double layer model for a monopolar core is extended to represent the nanofiller/nanocrystallite by replacing it with a dipolar core. Charge injection at the electrodes assumes metal-polymer Schottky emission at low to moderate fields and Fowler-Nordheim tunneling at high fields. Injected particles propagate via field-dependent Poole-Frenkel mobility. The simulation algorithm uses a boundary integral equation method for solution of the Poisson equation coupled with a second-order predictor-corrector scheme for robust time integration of the equations of motion. The stability criterion of the explicit algorithm conforms to the Courant-Friedrichs-Levy limit assuring robust and rapid convergence. Simulation results for BaTiO3 nanofiller in amorphous polymer matrix and semicrystalline PVDF with varying degrees of crystallinity indicate that charge transport behavior depends on nanoparticle polarization with antiparallel orientation showing the highest conduction and therefore the lowest level of charge trapping in the interaction zone. Charge attachment to nanofillers and nanocrystallites increases with vol% loading or degree of crystallinity and saturates at 30–40 vol% for the set of simulation parameters.

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Кононов, Н. Н., Д. В. Давыдова, С. С. Бубенов, and С. Г. Дорофеев. "Электрические и оптические характеристики пленок из наночастиц Si, нанесенных на подложки высоковольтным электронапылением из золей в этаноле." Журнал технической физики 53, no. 4 (2019): 562. http://dx.doi.org/10.21883/ftp.2019.04.47458.8986.

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Abstract The paper describes the results of studying the optical and electrical characteristics of films made of silicon nanoparticles (nc-Si) deposited on substrates by high-voltage electrospray from sols of nc-Si in ethanol. It was found that the interaction of ethanol droplets carrying nc-Si with an electric field of corona discharge leads to polymerization of ethanol and formation of a polymer layer on the nanoparticle surface. The geometry and electric field strength in the flow area of ethanol droplets could be changed by means of the focusing electrode in the high-voltage device. As a result we could make nc-Si films with different kind of polymer layer on Si nanoparicle surface: nc-Si A and nc-Si B (the films deposited without and with focusing electrode, respectively). The optical band gap Eg of nc-Si A films increased from 1.9 to 2.2 eV after annealing at the temperatures from room one to 400◦C in air atmosphere. The Eg of the nc-Si B films was independent on annealing and was 1.85 eV. The constancy of Eg in nc-Si B films is explained by the polymer properties on the Si nanoparticles surface in these films and more effective blocking the penetration of oxygen atoms from the surrounding atmosphere during annealing to temperatures of 400◦C than in the case of the polymer in nc-Si A films. The temperature dependences of the conductivity (dark and photo) of nc-Si A films are approximated with good accuracy by two exponential functions, the dark activation energies of the films being approximately equal to 0.75 and 0.1 eV. The conductivity of nc-Si A films decreased noticeably when illuminated with radiation in the range 460−470 nm The temperature dependences of the conductivity of nc-Si B films with good accuracy is approximated by one-exponential function of the activation type with activation energies of 0.73 (dark) and 0.59 eV (photo). In contrast to the nc-Si A films, the photoconductivity of nc-Si B films increase by more than 4 times with respect to the dark conductivity when the films were illuminated anologically. The nc-Si B films are photoactive, since sandwich-like structures of Al/nc-Si B/Al can generate emf. The dark and photo-conductivity of nc-Si A films in the voltage range > 2V is determined by the two-center Poole−Frenkel effect, the concentration of the centers that determine the character of the Poole−Frenkel conductivity was 3 · 1017 cm−3. In nc-Si B films in the voltage range 2−5V, the electronic transport is determined by space-charge-limited currents (SCLC) and at higher voltages by the two-center Pool−Frenkel conduction. The concentration of traps contributing to SCLC in the films is 4 · 1016 cm−3. The concentration of the Pool−Frenkel centers, decreases from 3 · 1016 to 2 · 1014 cm−3 with decreasing temperature in the range 120−400◦C according to the activation law with an activation energy of 0.7 eV.

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Hussain, A., P. Akhter, and A. S. Bhatti. "Charge Transport Mechanism and the Effects of Device Temperature on Electrical Parameters of Au/ZnPc/N-Si Structures." Key Engineering Materials 442 (June 2010): 372–80. http://dx.doi.org/10.4028/www.scientific.net/kem.442.372.

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Gold/Zinc Phthalocyanine/n-Si metal semiconductor contact with organic interfacial layer have been developed and characterized by Current–Voltage-Temperature (I-V-T) measurements, to study its junction and charge transport properties. The junction parameters, of diode ideality factor (n), barrier height (b) and series resistance (R¬S), of the device are found to shift with device temperature. The barrier height and the diode ideality factor are found to increase and the series resistance is found to decrease with increasing device temperature. The activation energy of the charge carriers is found to be 44 meV and the peak of interface state energy distribution curves is found to shift in terms of Ess-Ev value from 0.582 eV to 0.776 eV with increasing device temperature. The data analysis implies that the Fermi level of the organic interfacial layer shifts as function of device temperature by 100 meV in the device temperature range of 283K to 343K. In terms of dominant conduction mechanism, the I-V-T data analysis confirms the fit of data to the relationship log (IV4)  V1/2 for higher device temperatures and the Poole-Frenkel type is found to be the dominant conduction mechanism for the hybrid device.

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Kim, Hogyoung, Seok Choi, and Byung Joon Choi. "Influence of AlN and GaN Pulse Ratios in Thermal Atomic Layer Deposited AlGaN on the Electrical Properties of AlGaN/GaN Schottky Diodes." Coatings 10, no. 5 (May 19, 2020): 489. http://dx.doi.org/10.3390/coatings10050489.

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Atomic layer deposited AlGaN with different AlN and GaN pulse ratios (2:1, 1:1, and 1:2) was used to prepare AlGaN/GaN Schottky diodes, and their current transport mechanisms were investigated using current–voltage (I–V) and capacitance–voltage (C–V) measurements. Under low reverse bias condition, the sample with the pulse ratio of 2:1 was explained by Poole–Frenkel emission and the negative temperature dependence for the sample with the pulse ratio of 1:2 was associated with the acceptor levels in the AlGaN layer. Fast interface traps at 0.24–0.29 eV were observed for the samples with the pulse ratios of 1:1 and 1:2, whereas bulk traps at ~0.34 eV were observed for the sample with the pulse ratio of 2:1. Higher trap densities were obtained from the C–V hysteresis measurements when the pulse ratios were 1:1 and 1:2, indicating the presence of a charge trapping interfacial layer. According to the X-ray photoelectron spectroscopy spectra, the pulse ratio of 2:1 was found to have less oxygen-related defects in the AlGaN layer.

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Postel-Pellerin, Jérémy, Gilles Micolau, Philippe Chiquet, Maminirina Joelson, and Jean-Baptiste Decitre. "A global modeling approach of the leakage phenomena in dielectrics." E3S Web of Conferences 88 (2019): 05002. http://dx.doi.org/10.1051/e3sconf/20198805002.

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Thanks to its low noise level, the LSBB environment provides particular environment to carry out high quality electrical characterizations. In this paper, we propose a complete modeling approach of the experimental results from our experimental microelectronic setup. The tested device is a Metal Oxide Semiconductor (MOS) floating gate capacitor which can be found in electrostatic non volatile memories such as Flash. The main idea is to characterize and model the leakage current through the tunnel oxide. We proposed, in a previous work, a model for charge loss considering a fractional Poisson process, involving only two parameters, expressed as a Mittag-Leffler (ML) function. Here, we also propose a combo of Fowler-Nordheim (FN) and Poole-Frenkel (PF) models for leakage currents, based on tunnel effect transport through the oxide. It gives the leakage current on a medium-to-long scale of time while the ML model can possibly take into account a shorter time step. The perspective is to find a relationship between these different models, used in various fields, to propose a generic model of phenomena involving leakage in complex and porous materials at different scales of time and space.

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Martínez, Haydee P., José A. Luna, Roberto Morales, José F. Casco, José A. D. Hernández, Adan Luna, Zaira J. Hernández, et al. "Blue Electroluminescence in SRO-HFCVD Films." Nanomaterials 11, no. 4 (April 8, 2021): 943. http://dx.doi.org/10.3390/nano11040943.

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In this work, electroluminescence in Metal-Insulator-Semiconductors (MIS) and Metal-Insulator-Metal (MIM)-type structures was studied. These structures were fabricated with single- and double-layer silicon-rich-oxide (SRO) films by means of Hot Filament Chemical Vapor Deposition (HFCVD), gold and indium tin oxide (ITO) were used on silicon and quartz substrates as a back and front contact, respectively. The thickness, refractive indices, and excess silicon of the SRO films were analyzed. The behavior of the MIS and MIM-type structures and the effects of the pristine current-voltage (I-V) curves with high and low conduction states are presented. The structures exhibit different conduction mechanisms as the Ohmic, Poole–Frenkel, Fowler–Nordheim, and Hopping that contribute to carrier transport in the SRO films. These conduction mechanisms are related to the electroluminescence spectra obtained from the MIS and MIM-like structures with SRO films. The electroluminescence present in these structures has shown bright dots in the low current of 36 uA with a voltage of −20 V to −50 V. However, when applied voltages greater than −67 V with 270 uA, a full area with uniform blue light emission is shown.

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Muralidharan, Pradyumna, Stephen M. Goodnick, and Dragica Vasileska. "Multiscale modeling of transport in silicon heterojunction solar cells." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2017, DPC (January 1, 2017): 1–15. http://dx.doi.org/10.4071/2017dpc-tha3_presentation1.

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Silicon based single junction solar cell technology continued to make significant strides in the past year with new world record module efficiencies being reported for the Panasonic heterojunction with thin intrinsic layer (HIT) module (23.8%) and the SunPower rooftop silicon module (24.1%). The HIT cell which is comprised of amorphous silicon (a-Si) and crystalline silicon (c-Si) currently holds the world record efficiency (25.6%) for a silicon based single junction solar cell. Further improvement in this technology requires a rigorous understanding of the underlying physics of the device. The device performance of a-Si and c-Si heterojunction solar cells depends heavily on the nature of transport at the hetero interface and defect assisted transport through the a-Si. Different microscopic processes dominate transport in different regions of the device and take place across widely varying time scales. In this work we present a multiscale model which utilizes different simulation methodologies to study physics in various regions of the device, namely, the Ensemble Monte Carlo (EMC), Kinetic Monte Carlo (KMC), and Drift Diffusion (DD) solvers. The EMC studies the behavior of the photogenerated carriers at the heterointerface; the KMC analyzes transport of the photogenerated carriers through the intrinsic amorphous silicon (i-a-Si) barrier layer; and the DD solver calculates current and other device properties in the low field regions of the cell. These solvers are then self consistently coupled to analyze device performance. Previously, our KMC simulations have shown that hopping is the main mode of transport through the i-a-Si, and the photogenerated carries are collected by defect emission rather that Poole - Frenkel emission or direct tunneling1. In addition, using EMC simulations we have shown that the photogenerated carriers exhibit non Maxwellian behavior at the heterointerface2. This work specifically describes the self-consistent coupling of the DD and EMC solvers. By adding the EMC solver to the multiscale solver we are able to capture the high field behavior of the photogenerated carriers, and its affect on device parameters such as JSC, VOC, FF and efficiency.

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LUCOVSKY, GERALD. "PART II: CONDUCTION BAND-EDGE STATES ASSOCIATED WITH REMOVAL OF d-STATE DEGENERACIES BY THE STATIC JAHN-TELLER EFFECT." International Journal of High Speed Electronics and Systems 16, no. 01 (March 2006): 263–300. http://dx.doi.org/10.1142/s0129156406003643.

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X-ray absorption spectroscopy (XAS) is used to study band edge electronic structure of high-k transition metal (TM) and trivalent lanthanide rare earth (RE) oxide dielectrics. The lowest conduction band d*-states in nano-crystalline TiO 2, ZrO 2 and HfO 2 are correlated with features in the O K 1 edge, and transitions from occupied Ti 2p, Zr 3p and Hf 4p states to empty Ti 3d-, Zr 4d-, and Hf 5d-states, respectively. Optical band gaps, E opt , and conduction band offset energy with respect to Si , E B , scale monotonically with d-state energies of the TM/RE atoms. The multiplicity of d-state features in the Ti L 2,3 spectrum of TiO 2, and the O K 1 derivative spectra for ZrO 2 and HfO 2 indicate a complete removal of d-state degeneracies resulting from a static Jahn-Teller effect. Similar degeneracy removals are shown for complex nano-crystalline TM/RE oxides such as Zr and Hf titanates, and La , Gd and Dy scandates. XAS and band edge spectra indicate an additional band edge defect state assigned Jahn-Teller distortions at internal grain boundaries. These defect states are electronically active act as bulk traps in metal oxide semiconductor (MOS) devices, contributing to asymmetries in tunneling and Frenkel-Poole transport with important consequences for performance and reliability in advanced Si devices.

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Popov, Vladimir P., Fedor V. Tikhonenko, Valentin A. Antonov, Ida E. Tyschenko, Andrey V. Miakonkikh, Sergey G. Simakin, and Konstantin V. Rudenko. "Diode-Like Current Leakage and Ferroelectric Switching in Silicon SIS Structures with Hafnia-Alumina Nanolaminates." Nanomaterials 11, no. 2 (January 22, 2021): 291. http://dx.doi.org/10.3390/nano11020291.

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Silicon semiconductor-insulator-semiconductor (SIS) structures with high-k dielectrics are a promising new material for photonic and CMOS integrations. The “diode-like” currents through the symmetric atomic layer deposited (ALD) HfO2/Al2O3/HfO2… nanolayers with a highest rectification coefficient 103 are observed and explained by the asymmetry of the upper and lower heterointerfaces formed by bonding and ALD processes. As a result, different spatial charge regions (SCRs) are formed on both insulator sides. The lowest leakages are observed through the stacks, with total Al2O3 thickness values of 8–10 nm, which also provide a diffusive barrier for hydrogen. The dominant mechanism of electron transport through the built-in insulator at the weak field E < 1 MV/cm is thermionic emission. The Poole-Frenkel (PF) mechanism of emission from traps dominates at larger E values. The charge carriers mobility 100–120 cm2/(V s) and interface states (IFS) density 1.2 × 1011 cm−2 are obtained for the n-p SIS structures with insulator HfO2:Al2O3 (10:1) after rapid thermal annealing (RTA) at 800 °C. The drain current hysteresis of pseudo-metal-oxide-semiconductor field effect transistor (MOSFET) with the memory window 1.2–1.3 V at the gate voltage |Vg| < ±2.5 V is maintained in the RTA treatment at T = 800–900 °C for these transistors.

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Abdeldaym, A., and MA Elhady. "Role of copper oxide nanoparticles and gamma irradiation in optimising mechanical and the DC-electrical properties of nylon 66." Journal of Composite Materials 54, no. 24 (April 11, 2020): 3595–610. http://dx.doi.org/10.1177/0021998320918347.

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This study used an aqueous precipitation method to synthesise copper oxide (CuO) nanoparticles. Nylon 66/CuO-based nanocomposites were prepared through a melt-mixing process using CuO nanoparticles with differing contents (1, 2, 3 and 4 wt%) and varying doses of gamma radiation (100, 200 and 300 kGy). The study also investigated the impact of these combinations on the structural, mechanical and DC-electrical attributes of nylon 66. The combination of CuO nanoparticles and gamma irradiation caused nylon 66 to undergo structural changes verified through X-ray diffraction measurement and Fourier-transform infrared spectroscopy. Scanning electron microscopy was used to examine the morphology of the nylon 66/CuO nanocomposites and revealed that the CuO nanoparticles belonging to the nylon 66 matrixes had a homogeneous dispersion. According to the mechanical finding, the influence of CuO nanoparticles and gamma irradiation significantly augmented the flexural strength and flexural modulus of the nanocomposites. However, this addition led to a decline of elongation at break. To better understand the tensile mechanism, a correlation of tensile strength using theoretical models premised on Money, Einstein and Pukanszky were undertaken. The optimal deviation was exhibited by the Pukanszky model using tensile plots on an experimental basis. The study also examined the nanocomposite’s DC-electrical conductivity; electrical conductivity increased with CuO nanoparticle content and gamma irradiation. For every sample, the prevailing transport mechanism was the Poole–Frenkel emission. This finding is encouraging for the development of innovative materials with augmented tensile strength and nanoelectronic devices.

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Gnatyuk, Volodymyr, Olena Maslyanchuk, Mykhailo Solovan, Viktor Brus, and Toru Aoki. "CdTe X/γ-ray Detectors with Different Contact Materials." Sensors 21, no. 10 (May 18, 2021): 3518. http://dx.doi.org/10.3390/s21103518.

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Different contact materials and optimization of techniques of their depositions expand the possibilities to obtain high performance room temperature CdTe-based X/γ-ray detectors. The heterostructures with ohmic (MoOx) and Schottky (MoOx, TiOx, TiN, and In) contacts, created by DC reactive magnetron sputtering and vacuum thermal evaporation, as well as In/CdTe/Au diodes with a p-n junction, formed by laser-induced doping, have been developed and investigated. Depending on the surface pre-treatment of semi-insulating p-CdTe crystals, the deposition of a MoOx film formed either ohmic or Schottky contacts. Based on the calculations and I-V characteristics of the Mo-MoOx/p-CdTe/MoOx-Mo, In/p-CdTe/MoOx-Mo, Ti-TiOx/p-CdTe/MoOx-Mo, and Ti-TiN/p-CdTe/MoOx-Mo Schottky-diode detectors, the current transport processes were described in the models of the carrier generation–recombination within the space-charge region (SCR) at low bias, and space-charge limited current incorporating the Poole–Frenkel effect at higher voltages, respectively. The energies of generation–recombination centers, density of trapping centers, and effective carrier lifetimes were determined. Nanosecond laser irradiation of the In electrode, pre-deposited on the p-CdTe crystals, resulted in extending the voltage range, corresponding to the carrier generation–recombination in the SCR in the I-V characteristics of the In/CdTe/Au diodes. Such In/CdTe/Au p-n junction diode detectors demonstrated high energy resolutions (7%@59.5 keV, 4%@122 keV, and 1.6%@662 keV).

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29

Alema, Fikadu, and Konstantin Pokhodnya. "Dielectric properties of BaMg1∕3Nb2∕3O3 doped Ba0.45Sr0.55Tio3 thin films for tunable microwave applications." Journal of Advanced Dielectrics 05, no. 04 (December 2015): 1550030. http://dx.doi.org/10.1142/s2010135x15500307.

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Ba(Mg[Formula: see text]Nb[Formula: see text]O3 (BMN) doped and undoped Ba[Formula: see text]Sr[Formula: see text]TiO3 (BST) thin films were deposited via radio frequency magnetron sputtering on Pt/TiO2/SiO2/Al2O3 substrates. The surface morphology and chemical state analyses of the films have shown that the BMN doped BST film has a smoother surface with reduced oxygen vacancy, resulting in an improved insulating properties of the BST film. Dielectric tunability, loss, and leakage current (LC) of the undoped and BMN doped BST thin films were studied. The BMN dopant has remarkably reduced the dielectric loss ([Formula: see text]38%) with no significant effect on the tunability of the BST film, leading to an increase in figure of merit (FOM). This is attributed to the opposing behavior of large Mg[Formula: see text] whose detrimental effect on tunability is partially compensated by small Nb[Formula: see text] as the two substitute Ti[Formula: see text] in the BST. The coupling between [Formula: see text] and V[Formula: see text] charged defects suppresses the dielectric loss in the film by cutting electrons from hopping between Ti ions. The LC of the films was investigated in the temperature range of 300–450[Formula: see text]K. A reduced LC measured for the BMN doped BST film was correlated to the formation of defect dipoles from [Formula: see text], V[Formula: see text] and Nb[Formula: see text] charged defects. The carrier transport properties of the films were analyzed in light of Schottky thermionic emission (SE) and Poole–Frenkel (PF) emission mechanisms. The result indicated that while the carrier transport mechanism in the undoped film is interface limited (SE), the conduction in the BMN doped film was dominated by bulk processes (PF). The change of the conduction mechanism from SE to PF as a result of BMN doping is attributed to the presence of uncoupled Nb[Formula: see text] sitting as a positive trap center at the shallow donor level of the BST.

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30

Muralidharan, Pradyumna, Stuart Bowden, Stephen M. Goodnick, and Dragica Vasileska. "A Multiscale Modeling Approach to Study Transport in Silicon Heterojunction Solar Cells." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2016, DPC (January 1, 2016): 002095–110. http://dx.doi.org/10.4071/2016dpc-tha33.

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Single junction solar cells based on Silicon continue to be relevant and commercially successful in the market due to their high efficiencies and relatively low cost processing. Heterojunction solar cells based on crystalline (c-Si) and amorphous (a-Si) silicon (HIT Cells) have paved the way for devices with high VOC's (>700 mV) and high efficiencies (>20%) [1]. Panasonic currently holds the world record efficiency of 25.6% for its trademark a-Si/c-Si HIT cell [2]. The novel structure of the device precludes the usage of traditional methods (such as drift diffusion) to accurately understand the nature of transport. Theoretical models used by commercial simulators make a variety of assumptions that simplifies the transport problem (assumes a Maxwellian distribution of carriers) and thus lacks the sophistication to study defect transport. In this work we utilize a combination of Ensemble Monte Carlo (EMC) simulations, Kinetic Monte Carlo (KMC) simulations and traditional drift - diffusion (DD) simulations to study transport in the heterojunction solar cell. The device performance of an amorphous silicon (a-Si)/crystalline silicon (c-Si) solar cell depends strongly on the interfacial transport properties of the device [3]. The energy of the photogenerated carriers at the barrier strongly depends on the strength of the inversion at the heterointerface and their collection requires interaction with the defects present in the intrinsic amorphous silicon buffer layer [4]. In this work we present a multiscale model which can bridge the gap in time scales between different microscopic processes to study the transport through the interface by coupling an ensemble Monte Carlo (EMC) and a kinetic Monte Carlo (KMC). The EMC studies carrier properties such as the energy distribution function (EDF) at the heterointerface whereas the KMC method allows us to simulate the interaction of discrete carriers with discrete defects [5]. This method allows us to study defect transport which takes place on a time scale which is too long for traditional ensemble Monte Carlo's to analyze. We analyze the injection and extraction of carriers via defects by calculating transition rates for different processes. By using the principles of SRH recombination, this method can also be extended to study recombination processes at the interface and in the amorphous bulk which are crucial parameters for solar cell performance. Therefore, by using the multiscale approach all important processes can be studied rigorously to evaluate device performance. Our simulations indicate that a phonon assisted emission process from a defect is the most favored extraction mechanism and both Poole-Frenkel emission (<2%) and thermionic emission (<1%) were not significant. We extended our simulation methodology to study recombination at the interface and in the buffer layer of the device to find that the device performance is mainly interface recombination limited and that defect densities in the buffer layer have to be really high (>1018 cm-3) in order to degrade device performance.

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31

Pal, Chandana, Isabelle Chambrier, Andrew N. Cammidge, A. K. Sharma, and Asim K. Ray. "Steady state charge conduction through solution processed liquid crystalline lanthanide bisphthalocyanine films." Journal of Porphyrins and Phthalocyanines 23, no. 11n12 (December 2019): 1603–15. http://dx.doi.org/10.1142/s1088424619501918.

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In-plane electrical characteristics of non-peripherally octyl(C[Formula: see text]H[Formula: see text]- and hexyl(C[Formula: see text]H[Formula: see text]-substituted liquid crystalline (LC) double decker lanthanide bisphthalocyanine (LnPc[Formula: see text] complexes with central metal ions lutetium (Lu), and gadolinium (Gd) have been measured in thin film formulations on interdigitated gold (Au) electrodes for the applied voltage ([Formula: see text] range of [Formula: see text]. The conduction mechanism is found to be Ohmic within the bias of [Formula: see text] while the bulk limited Poole–Frenkel mechanism is responsible for the higher bias. The compounds show individual characteristics depending on the central metal ions, substituent chain lengths and their mesophases. Values of 67.55 [Formula: see text]cm[Formula: see text] and 42.31 [Formula: see text]cm[Formula: see text] have been obtained for room temperature in-plane Ohmic conductivity of as-deposited octyl lutetium (C[Formula: see text]LuPc[Formula: see text] and hexyl gadolinium (C[Formula: see text]GdPc[Formula: see text] films, respectively while C[Formula: see text]GdPc[Formula: see text] films exhibit nearly two orders of magnitude smaller conductivity. On annealing at 80[Formula: see text]C, Ohmic conductivities of C[Formula: see text]LuPc[Formula: see text] and C[Formula: see text]GdPc[Formula: see text] are found to have increased but the conductivity of C[Formula: see text]GdPc[Formula: see text] decreased by more than one order of magnitude to 1.5 [Formula: see text]cm[Formula: see text]. For physical interpretation of the charge transport behavior of these three molecules, their UV-vis optical absorption spectra in the solution and in as-deposited and annealed solid phases and atomic force microscopy study have been performed. It is believed that both orientation and positional reorganizations are responsible, depending upon the size of the central ion and side chain length.

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32

ANWAR, M., S. A. SIDDIQI, and I. M. GHAURI. "DC CONDUCTION MECHANISMS IN AMORPHOUS THIN FILMS OF MIXED OXIDES In2O3–SnO2 SYSTEM DEPOSITED BY CO-EVAPORATION." International Journal of Modern Physics B 20, no. 15 (June 20, 2006): 2159–74. http://dx.doi.org/10.1142/s021797920603456x.

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A discussion of dc conduction mechanisms in thermally co-evaporated amorphous thin films of Al – In 2 O 3– SnO 2– Al structure is presented. Composition (in molar %), film thickness, substrate temperature, and post deposition annealing have profound effects on the electrical properties of the films. The effects of temperature on the I – V characteristics and electrical conductivity of Al – In 2 O 3– SnO 2– Al structure are also reported. The values of dielectric constants estimated by capacitance measurements suggest that high-field conduction mechanism is predominantly of Poole–Frenkel type. At low temperature and low field the electron hopping process dominates but at higher temperature the conduction takes place by transport in the extended states (free-band conduction). The transition from hopping to free band conduction is due to overlapping of localized levels and the free band. The increase in the formation of ionized donors with increase in temperature during electrical measurements indicates that electronic part of the conductivity is higher than the ionic part. The initial increase in conductivity with increase in Sn content in In 2 O 3 lattice is caused by the Sn atom substitution of In atom, giving out one extra electron. The decrease in electrical conductivity above the critical Sn content (10 mol % SnO 2) is caused by the defects formed by Sn atoms, which act as carrier traps rather than electron donors. The increase in electrical conductivity with film thickness is caused by the increase in free carriers density, which is generated by oxygen vacancy acting as two electrons donor. The increase in conductivity with substrate temperature and annealing is due either to the severe deficiency of oxygen, which deteriorates the film properties and reduces the mobility of the carriers or to the diffusion of Sn atoms from interstitial locations into the In cation sites and formation of indium species of lower valence state so that the In 3+ oxidation state may be changed to the In 2+ oxidation state.

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33

Yang, Ming-Cong, Jun-ichi Hanna, and Hiroaki Iino. "Novel calamitic liquid crystalline organic semiconductors based on electron-deficient dibenzo[c,h][2,6]naphthyridine: synthesis, mesophase, and charge transport properties by the time-of-flight technique." Journal of Materials Chemistry C 7, no. 42 (2019): 13192–202. http://dx.doi.org/10.1039/c9tc03990b.

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34

NITHYAPRAKASH, D., B. PUNITHAVENI, and J. CHANDRASEKARAN. "TRANSPORT PROPERTIES OF THERMALLY EVAPORATED In2Se3 THIN FILMS." Surface Review and Letters 16, no. 05 (October 2009): 723–29. http://dx.doi.org/10.1142/s0218625x09013293.

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Thin films of In2Se3 were prepared by thermal evaporation. X-ray diffraction indicated that the as-grown films were amorphous in nature and became polycrystalline γ-In2Se3 films after annealing. The ac conductivity and dielectric properties of In2Se3 films have been investigated in the frequency range 100 Hz–100 kHz. The ac conductivity σ ac is found to be proportional to ωn where n < 1. The temperature dependence of both ac conductivity and the parameter n is reasonably well interpreted by the correlated barrier hopping (CBH) model. The values of dielectric constant ε and loss tangent tan δ were found to increase with frequency and temperature. The ac conductivity of the films was found to be hopping mechanism. In I–V characteristic for different field and temperature were studied and it has been found that the conduction process is Poole–Frenkel type.

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35

Mahmood, K., and Nadeem Sabir. "Interface-Controlled Carrier Transport in Metal-Lutetium Oxide-Metal Structures Deposited by Electron-Beam Evaporation Technique." MRS Advances 2, no. 44 (2017): 2373–78. http://dx.doi.org/10.1557/adv.2017.322.

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ABSTRACTNano-thin films of Lu2O3 with 80nm thickness have been deposited on metal-coated glass substrate in metal-insulator-metal (MIM) geometry by electron-beam evaporation technique. High field and temperature dependent electrical characterization on grown MIM structures have been investigated in symmetric electrode configuration using Al, Cr or Cu metals. The temperature dependent I-T characteristic features have been found to support the conduction mechanism across MIM systems to be an electrode-limited process except for Al-Lu2O3-Al device, which show Poole-Frenkel mechanism in high electric field region. The associated parameters such as activation energy (∆E), coefficient of barrier lowering (β) and effective height of Schottky barrier at zero biasing (Фo) have been evaluated at different values of temperature and electric field to further investigate the dominent conduction mechanism.

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36

Marat-Mendes, José N., Eugen R. Neagu, and Rodica M. Neagu. "Electric Charge Trapping and Transport at Medium Fields in Low-Density Polyethylene." Materials Science Forum 480-481 (March 2005): 495–500. http://dx.doi.org/10.4028/www.scientific.net/msf.480-481.495.

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The transient conductivity in low-density polyethylene is studied. Isochronal currentvoltage measurements for 1800 s and 1 day time intervals are carried out under dry N2 atmosphere. When after every measurement the sample is fully discharged at high temperature the isochronal current - voltage characteristic reveals an ohmic behavior. When the next field increase is applied without sample discharging the current-voltage characteristic is super-quadratic. We explain this increase of the current assuming that a fraction of the previous injected charge is detrapped by the field and it contributes to current increase. Consequently the current – voltage characteristic is strongly dependent on the time lag between two successive rises in the field. Neither the Poole-Frenkel mechanism nor the Richardson – Schottky mechanism can by used to explain the experimental results. The isothermal charging and discharging currents are explained assuming the movement of injected/ejected charge in the resultant local field. The values obtained for the adjustable parameters of the model are in good agreement with the values in the literature.

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37

Sahoo, Santosh K., H. Bakhru, Sumit Kumar, D. Misra, Colin A. Wolden, Y. N. Mohapatra, and D. C. Agrawal. "Field Dependent Carrier Transport Mechanisms in Metal-Insulator–Metal Devices with Ba0.8Sr0.2TiO3/ ZrO2 Heterostructured Thin Films as the Dielectric." MRS Proceedings 1547 (2013): 53–60. http://dx.doi.org/10.1557/opl.2013.855.

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ABSTRACTBa0.8Sr0.2TiO3/ZrO2 heterostructured thin films with different individual layer ZrO2 thicknesses are deposited on Pt/Ti/SiO2/Si substrates by a sol-gel process. The current versus voltage (I-V) measurements of the above multilayered thin films in metal-insulator-metal (MIM) device structures are taken in the temperature range of 310 to 410K. The electrical conduction mechanisms contributing to the leakage current at different field regions have been studied in this work. Various models are used to know the different conduction mechanisms responsible for the leakage current in these devices. It is observed that Poole-Frenkel mechanism is the dominant conduction process in the high field region with deep electron trap energy levels (φt) whereas space charge limited current (SCLC) mechanism is contributing to the leakage current in the medium field region with shallow electron trap levels (Et). Also, it is seen that Ohmic conduction process is the dominant mechanism in the low field region having activation energy (Ea) for the electrons. The estimated trap level energy varies from 0.2 to 1.31 eV for deep level traps and from 0.08 to 0.18 eV for shallow level traps whereas the activation energy for electrons in ohmic conduction process varies from 0.05 to 0.17 eV with the increase of ZrO2 sub layer thickness. An energy band diagram is given to explain the dominance of the various leakage mechanisms in different field regions for these heterostructured thin films.

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38

Habermehl, S., and C. Carmignani. "Charge Transport in Low Stress Si-rich Silicon Nitride Thin Films." MRS Proceedings 687 (2001). http://dx.doi.org/10.1557/proc-687-b5.11.

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AbstractField dependent bulk charge transport in Si-rich, low stress silicon nitride thin films is studied in correlation to the local atomic Si-N bond strain. Across a range of film compositions varying from fully stoichiometric Si3N4 to Si-rich SiN0.54, Poole-Frenkel emission is determined to be the dominant charge transport mechanism with the Poole- Frenkel barrier height found to decrease concomitantly from 1.10 to 0.52 eV. Across the same composition range the local residual Si-N bond strain, as measured by FTIR spectroscopy, is observed to vary from 0.006 to –0.0026. Comparison of the barrier height to the residual strain reveals a direct correlation between the two quantities. It is concluded that reductions in the Poole-Frenkel barrier height are a manifestation of compositionally induced strain relief at the molecular level. Reductions in the barrier height result in increased Poole-Frenkel emission detrapping rates and consequently higher leakage currents in Si-rich films.

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39

Hamadani, Behrang H., and Douglas Natelson. "Gated Nonlinear Transport in Organic Thin Film Transistors." MRS Proceedings 771 (2003). http://dx.doi.org/10.1557/proc-771-l6.10.

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AbstractCharge transport in poly(3-hexylthiophene) field effect transistors has been studied in a series of devices with channel lengths ranging from 3 μm down to 200 nm over a broad range of temperatures and gate voltages. We report gate-modulated highly nonlinear transport at temperatures below ∼200 K that is consistent in form with a Poole-Frenkel-like hopping mechanism in the space charge limited current regime. There is also consistency between this behavior and the hypothesis that density of localized states is strongly energy dependent. We also observe what appears to be a crossover from thermally activated to nonthermal hopping below 30 K.

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40

Liu, Jie, Xu Xu, and M. P. Anantram. "Ab Initio Study of the Sub-threshold Electron Transport Properties of Ultra-scaled Amorphous Phase Change Material Germanium Telluride." MRS Proceedings 1697 (2014). http://dx.doi.org/10.1557/opl.2014.423.

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ABSTRACTThe sub-threshold electron transport properties of amorphous (a-) germanium telluride (GeTe) phase change material (PCM) ultra-thin films are investigated by using ab initio molecular dynamics, density function theory, and Green’s function simulations. The simulation results reproduce the trends in measured electron transport properties, e.g. current-voltage curve, intra-bandgap donor-like and acceptor-like defect states, and p-type conductivity. The underlying physical mechanism of electron transport in ultra-scaled a-PCM is unraveled. We find that, though the current-voltage curve of the ultra-scaled a-PCM resembles that of the bulk a-PCM, their physical origins are different. Unlike the electron transport in bulk a-PCM, which is governed by the Poole-Frenkel effect, the electron transport in ultra-scaled a-PCM is largely dominated by tunneling transport via intra-bandgap donor-like and acceptor-like defect states.

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41

Lau, S. P., J. M. Shannon, B. J. Sealy, and J. M. Marshall. "The Role of Charged Defects In Current Transport Through Hydrogenated Amorphous Silicon Alloys." MRS Proceedings 507 (1998). http://dx.doi.org/10.1557/proc-507-655.

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ABSTRACTCurrent transport in metal-semiconductor-metal structures based on amorphous silicon alloys has been studied in relation to the density of dangling bond state defects. The density of defects was changed by varying alloy composition or by current stressing. We show that the change of current-voltage characteristics and activation energy with defect density and the onset of Poole-Frenkel conduction with composition require charged defects. It is found that there are more charged defects in amorphous silicon nitride (a-Si1−xNx:H) than in amorphous silicon carbide (a-Si1−xCx:H). In addition, an excess of negatively charged dangling bond defects compared to positively charged dangling bond defects is observed in a-Si1−xNx:H films. This is attributed to the presence of N4+ act as the donor states in silicon nitride. We find that the density of charged dangling bond defects can be higher than 1019cm−3.

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Yang, Chia-Han, Yue Kuo, Chen-Han Lin, and Way Kuo. "Temperature Effects on Charge Transfer Mechanisms of nc-ITO Embedded ZrHfO High-k Nonvolatile Memory Devices." MRS Proceedings 1337 (2011). http://dx.doi.org/10.1557/opl.2011.1068.

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ABSTRACTThe nanocrystalline ITO embedded Zr-doped HfO2 high-k dielectric thin film has been made into MOS capacitors for nonvolatile memory studies. The devices showed large charge storage densities, large memory windows, and long charge retention times. In this paper, authors investigated the temperature effect on the charge transport and reliability of this kind of device in the range of 25°C to 125°C. The memory window increased with the increase of the temperature. The temperature influenced the trap and detrap of not only the deeply-trapped but also the loosely-trapped charges. The device lost its charge retention capability with the increase of the temperature. The Schottky emission relationship fitted the device in the positive gate voltage region. However, the Frenkel-Poole mechanism was suitable in the negative gate voltage region.

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43

Jensen, Kevin L. "Electron Transmission Through Modified Schottky Barriers." MRS Proceedings 685 (2001). http://dx.doi.org/10.1557/proc-685-d14.4.1.

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AbstractThe effects of a Coulomb-like potential in the Schottky barrier existing between a material-diamond interface is analyzed. The inclusion is intended to mimic the effects of an ionized trap within the barrier, and therefore to account for charge injection into the conduction band of diamond via a Poole-Frenkel transport mechanism. The present treatment is to provide a qualitative account of the increase in current density near the inclusion, which can be substantial. The model is first reduced to an analytically tractable one-dimensional tunneling problem addressable by an Airy Function approach in order to investigate the nature of the effect. A more comprehensive numerical approach is then applied. Finally, statistical arguments are used to estimate emission site densities using the results of the aforementioned analysis.

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Liu, Jie, Xu Xu, and M. P. Anantram. "Role of Inelastic Electron-Phonon Scattering in Ultra-Scaled Phase Change Material Nanostructures." MRS Proceedings 1697 (2014). http://dx.doi.org/10.1557/opl.2014.692.

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ABSTRACTThe electron transport properties of ultra-scaled amorphous phase change material (PCM) GeTe are studied using non-equilibrium Green’s function (NEGF). The inelastic electron-phonon scattering is included using Born approximation. It is shown that, in ultra-scaled PCM device with 6 nm channel length, less than 4% of the energy carried by the incident electrons from the source is transferred to the atomic lattice before reaching the drain, indicating that the electron transport is largely elastic. Our simulation results show that the inelastic electron-phonon scattering, which plays an important role to excite trapped electrons in bulk PCM devices, exerts very limited influence on the current density value and the shape of current-voltage curve of ultra-scaled PCM devices. The analysis reveals that the Poole-Frenkel law and the Ohm’s law, which are the governing physical mechanisms of the bulk PCM devices, cease to be valid in the ultra-scaled PCM devices.

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45

Jauhiainen, Anders, Stefan Bengtsson, and Olof Engström. "Electrical Properties Of Undoped Polycrystalline Diamond Thin Films On Silicon." MRS Proceedings 416 (1995). http://dx.doi.org/10.1557/proc-416-331.

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ABSTRACTWe have investigated the electrical properties of undoped polycrystalline diamond thin films deposited on (100)-oriented n-type and p-type silicon substrates. The films, intended for electronic applications, were manufactured using hot filament chemical vapour deposition (HFCVD). To a large extent the capacitance-voltage characteristics are influenced by traps located close to the interface between the diamond layer and the silicon substrate. These traps play an important role for voltage sharing between the diamond layer and the silicon space charge region. The DC current density through the diamond film has the same functional dependence on the electric field for films deposited on both n- and p-Si. The field dependency agrees with a Frenkel-Poole transport model. Further, although the DC current transport is thermally activated, it does not follow an Arrhenius relation. A possible reason is that traps within a broad range of energy levels are involved in the charge transport. Finally, current transients resulting from stepwise changes in the applied voltage follow a power law time dependence where the kinetics depend only weakly on temperature.

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46

Mondon, François, Jacques Cluzel, Denis Blachier, Yves Morand, Laurent Martel, and Gilles Reimbold. "Electrical Characterization of Copper Penetration Effects in the Gate Oxide of MOS Devices." MRS Proceedings 714 (2001). http://dx.doi.org/10.1557/proc-714-l8.12.1.

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ABSTRACTCopper penetration in thermal oxide was investigated using MOS capacitors by annealing at 450 °C and bias-temperature stress at 250 °C. Copper induces minority carrier generation lifetime decay and oxide leakage current increase. Degradation is enhanced by capacitor biasing, which confirms the role of Cu+ ions. The current-voltage characteristics are consistent with Poole-Frenkel model, showing that electron transport proceeds through traps created in the oxide bulk by copper. When a negative bias is applied, copper traps are removed from oxide near SiO2-Si interface and the leakage current is cancelled but the generation lifetime remains nil, copper contamination of silicon surface being not removed.None of these effects are observed when the copper gate is separated from oxide by a 10 nm TiN layer, proving that this material is an efficient barrier against copper diffusion at 450°C.

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47

Cavallari, Marco R., Vinicius R. Zanchin, Cleber A. Amorim, Gerson dos Santos, Fernando J. Fonseca, Adnei M. Andrade, and Sergio Mergulhão. "Time-of-Flight Technique Limits of Applicability for Thin-Films of Π-Conjugated Polymers." MRS Proceedings 1402 (2012). http://dx.doi.org/10.1557/opl.2012.262.

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ABSTRACTTime of flight (ToF) is the most straightforward technique to determine polymeric semiconductor mobility for electronic applications. We demonstrate ToF limits of applicability to amorphous PPV derivatives, such as poly[2-methoxy-5-(3’,7’-dimethylloctyloxy)-1-4-phenylene vinylene] (MDMO-PPV) and poly[2-methoxy-5-(2’-ethylhexyloxy)-1-4-phenylene vinylene] (MEH-PPV), and polycrystalline poly(3-hexylthiophene) (P3HT). Hole and electron mobility (μ) in submicrometric films (200 – 500 nm) is overestimated compared to casted layers, due to reduced absorption capability, which is confirmed by Charge Extraction by Linearly Increasing Voltage (CELIV) measurements. Charge transport properties in nanometric films, such as for Field-Effect Transistors (FET), can not be studied by current-mode ToF. Hole mobility of ca. 10-5 cm2/Vs with Poole-Frenkel behavior for PPV derivatives and 10-3 cm2/Vs for P3HT is at least one order of magnitude higher than ToF results.

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Sabahi Namini, Abbas, Mehdi Shahedi Asl, Gholamreza Pirgholi-Givi, Seyed Ali Delbari, Javid Farazin, Şemsettin Altındal, and Yashar Azizian-Kalandaragh. "On the electrical characteristics of Al/p-Si diodes with and without (PVP: Sn-TeO2) interlayer using current–voltage (I–V) measurements." Applied Physics A 126, no. 12 (November 12, 2020). http://dx.doi.org/10.1007/s00339-020-04086-0.

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AbstractThe present study aims to investigate the effect of (PVP: Sn-TeO2) interfacial layer on the electrical parameters of the Al/p-Si diode. For this aim, (Sn-TeO2) nanostructures were developed by the ultrasound-assisted method, and both their electrical and optical characteristics were investigated by XRD, SEM, EDS, and UV–Vis methods. The bandgap of Sn-TeO2 was found as 4.65 eV from the (αhυ)2 vs (hυ) plot. The main electrical parameters of the Al/p-Si diodes with/ without (PVP: Sn-TeO2) interlayer, such as ideality factor (n), zero-bias barrier height (Φ0), and series resistance (Rs), were calculated by applying and comparing two methods of thermionic emission theory and Cheung’s functions. These results show that the presence of the (PVP: Sn-TeO2 interlayer, along with the increase of Φ0, and the decrease of n and Rs, led to a significant increment in the rectification of MPS when compared to MS diode. The current-transport mechanisms (CTMs) of them were examined through the forward LnIF − LnVF and reverse LnIR − VR0.5 bias currents, and then, the Poole–Frenkel and Schottky field-lowering coefficients (β) were calculated and obtained its value from the theoretical and experimental methods showed that the mechanism of the reverse current of MS and MPS diodes is governing by the Schottky emission and Pool-Frenkel mechanism, respectively.

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Satyala, Nikhil T., Wudyalew T. Wondmagegn, Ron J. Pieper, and Michael R. Korn. "Simulation of Copper Phthalocyanine (CuPc)/Fullerene (C60) Heterojunction. photovoltaic cell with and without electron transport layer (ETL)." MRS Proceedings 1212 (2009). http://dx.doi.org/10.1557/proc-1212-s08-18.

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AbstractA two-dimensional finite element simulation model for the bi-layer heterostructure organic photovoltaic (PV) cell, based on copper phthalocyanine (CuPc) and fullerene (C60) in the presence and absence of electron transport layers (ETLs) is presented. The effect of bathocuproine (BCP), tris(8-hydroxyquinolinato)aluminum (Alq3), and copper phthalocyanine (CuPc) as ETLs on short-circuit current (Jsc), open-circuit voltage (Voc), and power conversion efficiency (PCE) is investigated. The Frenkel-Poole mobility model was employed in describing the conduction mechanisms in the active layers. Singlet exciton and Langevin recombination techniques were employed to describe excitonic generation and recombination, respectively. The obtained simulation results demonstrate that the efficiency of PV cells is primarily dependent on the short-circuit current, the absorption capability of the active layers, and the charge collection efficiency at the electrodes. In addition, significant reduction in power conversion efficiency is observed with increasing thickness of the ETL layer. From among the modeled device designs, PV cells containing a 50Å BCP layer result in the best power conversion efficiencies of 2.05%.

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Simon, Mark Alexander, Marco Nardone, sergey Kostylev, Ilya V. Karpov, and Victor G. Karpov. "Charge Transport in Nanoglasses of Phase-Change Memory." MRS Proceedings 1251 (2010). http://dx.doi.org/10.1557/proc-1251-h01-11.

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AbstractWe discuss possible mechanisms for Poole-Frenkel type of non-ohmic conduction in chalcogenide glasses in the range of room temperatures. Overall, we list 8 such mechanisms, only one of which (Schottky emission) can be ruled out as inconsistent with the observations. Seven others can give more or less satisfactory fits of the observed non-linear IV curves. Our analysis calls upon indicative facts that would enable one to discriminate between the various alternative models.

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Journal articles on the topic 'Poole-Frenkel-Transport'

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