Transport model for disordered organic nanocomposites

2014 ◽  
Vol 1660 ◽  
Author(s):  
Andrés Vercik

ABSTRACTElectric transport in disordered media is usually explained in terms of different transport regimes, such as SCLC (Space Charge Limited Current) or TCLC (Trap Charge Limited Current) regimes. These models lead to exponential dependencies of the current on voltage, e.g., quadratic for SCLC or higher order for TCLC, with transition regions between them where fitting is poor. Alternatively, a statistical distribution in space and energy of the disordered traps, e.g., Gaussian or exponential, allows explaining transport in disordered materials. In this work, we propose a modeling based on the density of states (DOS) function, fitted from normalized differential conductivity curves obtained from experimental current-voltage curves. In general a Gaussian function is used for low energies whereas one or more exponential functions are used for higher energies. The proposed model is used to reproduce experimental current-voltage curves of organic nanocomposites, with gold and silver nanoparticles within chitosan matrixes. A unique expression is obtained for a very accurate fitting the experimental current-voltage characteristics in the whole voltage range without transition regions.

2014 ◽  
Vol 34 (2) ◽  
pp. 105-111 ◽  
Author(s):  
Germán Ayala Valencia ◽  
Jaiber Humberto Rodríguez Llanos ◽  
Luci Cristina de Oliveira Vercik ◽  
Andrés Vercik

Abstract The effect of gold nanoparticles (AuNPs) on the electronic transport in chitosan and chitosan/AuNPs films was experimentally and theoretically studied. The electronic properties (current-voltage curves) relative to the transport in the organic bulk in films were fitted to various models: space-charge limited current (SCLC), trap-charge limited current (TCLC) and scaling rule. However, it was found that the TCLC model, ITCLC(V)αVl+1 and scaling rule, I(V)α(V-VT)ξ, describes better the electronic transport in chitosan and chitosan/AuNPs films. Current-voltage (I-V) curves showed an increasing conductivity with the AuNPs concentration. In addition, a bistable behavior was observed in chitosan/AuNPs films and it was attributed to the electron capture in the AuNPs. The results reported in this paper indicate that the electronic conductivity and bistable behavior in chitosan/AuNPs films could be controlled by the AuNPs incorporation on the chitosan matrix.


2014 ◽  
Vol 573 ◽  
pp. 201-208 ◽  
Author(s):  
I.Sheik Arafat ◽  
N.B. Balamurugan ◽  
C. Priya

– In this paper, we have investigated the Scattering effects in Carrier Transport of Near-ballistic SiNW MOSFET, which incorporates elastic scattering, optical phonon emission and its combination with Roughness Scattering. Current–voltage (I–V) characteristics of Proposed model is compared with Natori’s Ballistic and Quasi-Ballistic Transport model. We study the impact of Surface Roughness in the device leads on the current variability of a Gate-All-Around (GAA) SiNW MOSFET, which shows a remarkable decrease in electric current, mobility variation and transconductance because of scattered mobility. Analog parameters like the transconductance (gm), the transconductance generation factor (gm/Id), the early voltage (VA) have also been investigated. Effectiveness of the proposed model has been confirmed by comparing the analytical results with the TCAD simulation results.


2020 ◽  
Vol 18 (1) ◽  
pp. 232-238
Author(s):  
Zhihong Zhang ◽  
Gailei Tian ◽  
Lin Han

AbstractSolute transport through the clay liner is a significant process in many waste landfills or unmanaged landfills. At present, researchers mainly focus on the test study about semi-membrane property of clay material, however, the influence of chemical osmosis caused by membrane effect on solute transport and fluid velocity is insufficient. In this investigation, based on the classical advection-diffusion equation, a one-dimensional solute transport model for low-permeable clay material has been proposed, in which the coupled fluid velocity related with hydraulic gradient and concentration gradient is introduced, and the semi-membrane effect is embodied in the diffusion mechanism. The influence of chemical osmosis on fluid velocity and solute transport has been analyzed using COMSOL Multiphysics software. The simulated results show that chemical osmosis has a significant retarded action on fluid velocity and pollutant transport. The proposed model can effectively reveal the change in process of coupled fluid velocity under dual gradient and solute transport, which can provide a theoretical guidance for similar fluid movement in engineering.


2021 ◽  
Vol 13 (7) ◽  
pp. 1318-1323
Author(s):  
Myeong-Cheol Shin ◽  
Dong-Hyeon Kim ◽  
Seong-Woo Jung ◽  
Michael A. Schweitz ◽  
Sang-Mo Koo

ABSTRACTThis study report on the formation of AlN/SiC heterostructure Schottky diodes for use of temperature sensing applications enhance the sensitivity. We analyzed the sensitivity of the AlN/SiC Schottky diode sensor depending on the annealing temperature. AlN/4H-SiC Schottky diodes were fabricated by depositing aluminum nitride (AlN) thin film on 4H/SiC by radio frequency sputtering. The forward bias electrical characteristics were determined under DC bias (in the voltage range of 0–1.5 V). The ideality factor, barrier height, and sensitivity were derived through current–voltage–temperature (I–V–T) measurements in the temperature range of 300–500 K. The sensitivity of the AlN/4H-SiC Schottky barrier diode ranged from 2.5–5.0 mV/K.


Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 98
Author(s):  
Eugeny Ryndin ◽  
Natalia Andreeva ◽  
Victor Luchinin

The article presents the results of the development and study of a combined circuitry (compact) model of thin metal oxide films based memristive elements, which makes it possible to simulate both bipolar switching processes and multilevel tuning of the memristor conductivity taking into account the statistical variability of parameters for both device-to-device and cycle-to-cycle switching. The equivalent circuit of the memristive element and the equation system of the proposed model are considered. The software implementation of the model in the MATLAB has been made. The results of modeling static current-voltage characteristics and transient processes during bipolar switching and multilevel turning of the conductivity of memristive elements are obtained. A good agreement between the simulation results and the measured current-voltage characteristics of memristors based on TiOx films (30 nm) and bilayer TiO2/Al2O3 structures (60 nm/5 nm) is demonstrated.


2015 ◽  
Vol 9 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Vandana Kumari ◽  
Anusaiya Kaswan ◽  
Dinesh Patidar ◽  
Narendra Saxena ◽  
Kananbala Sharma

Current-voltage characteristics and DC electrical conductivity were studied for Ge30-xSe70Snx (x = 8, 11, 14, 17 and 20) glassy thin pellets of diameter 12mm and thickness 1mm prepared under a constant load of 5 tons using a well-known melt quenching technique in bulk as a function of composition. The I-V characteristics were recorded at room temperature as well as elevated temperatures up to 300?C. The experimental data suggests that glass containing 20 at.% of Sn has the minimum resistance allowing maximum current through the sample as compared to other counterparts of the series. Therefore, DC conductivity is found to increase with increasing Sn concentration. Composition dependence of DC conductivity is discussed in terms of the bonding between Se and Sn. Plots between ln I and V1/2 provide linear relationship for both low and high voltage range. These results have been explained through the Pool-Frenkel mechanism. The I-V characteristics show ohmic behaviour in the low voltage range and this behaviour turns to non-ohmic from ohmic in the higher voltage range due to voltage induced temperature effects.


Author(s):  
Renjun Xu ◽  
Pelen Liu ◽  
Yin Zhang ◽  
Fang Cai ◽  
Jindong Wang ◽  
...  

Domain adaptation (DA) has achieved a resounding success to learn a good classifier by leveraging labeled data from a source domain to adapt to an unlabeled target domain. However, in a general setting when the target domain contains classes that are never observed in the source domain, namely in Open Set Domain Adaptation (OSDA), existing DA methods failed to work because of the interference of the extra unknown classes. This is a much more challenging problem, since it can easily result in negative transfer due to the mismatch between the unknown and known classes. Existing researches are susceptible to misclassification when target domain unknown samples in the feature space distributed near the decision boundary learned from the labeled source domain. To overcome this, we propose Joint Partial Optimal Transport (JPOT), fully utilizing information of not only the labeled source domain but also the discriminative representation of unknown class in the target domain. The proposed joint discriminative prototypical compactness loss can not only achieve intra-class compactness and inter-class separability, but also estimate the mean and variance of the unknown class through backpropagation, which remains intractable for previous methods due to the blindness about the structure of the unknown classes. To our best knowledge, this is the first optimal transport model for OSDA. Extensive experiments demonstrate that our proposed model can significantly boost the performance of open set domain adaptation on standard DA datasets.


2021 ◽  
Author(s):  
Di Wu

Ion-channel functions are often studied by the current-voltage relation, which is commonly fitted by the Boltzmann equation, a powerful model widely used nowadays. However, the Boltzmann model is restricted to a two-state ion-permeation process. Here we present an improved model that comprises a flexible number of states and incorporates both the single-channel conductance and the open-channel probability. Employing the channel properties derived from the single-channel recording experiments, the proposed model is able to describe various current-voltage relations, especially the reversal ion-permeation curves showing the inward- and outward-rectifications. We demonstrate the applicability of the proposed model using the published patch-clamp data of BK and MthK potassium channels, and discuss the similarity of the two channels based on the model studies.


2019 ◽  
Vol 9 ◽  
pp. 59-69
Author(s):  
Alok Dhaundiyal ◽  
Divine Atsu

This paper presents the modeling and simulation of the characteristics and electrical performance of photovoltaic (PV) solar modules. Genetic coding is applied to obtain the optimized values of parameters within the constraint limit using the software MATLAB. A single diode model is proposed, considering the series and shunt resistances, to study the impact of solar irradiance and temperature on the power-voltage (P-V) and current-voltage (I-V) characteristics and predict the output of solar PV modules. The validation of the model under the standard test conditions (STC) and different values of temperature and insolation is performed, as well as an evaluation using experimentally obtained data from outdoor operating PV modules. The obtained results are also subjected to comply with the manufacturer’s data to ensure that the proposed model does not violate the prescribed tolerance range. The range of variation in current and voltage lies in the domain of 8.21 – 8.5 A and 22 – 23 V, respectively; while the predicted solutions for current and voltage vary from 8.28 – 8.68 A and 23.79 – 24.44 V, respectively. The measured experimental power of the PV module estimated to be 148 – 152 W is predicted from the mathematical model and the obtained values of simulated solution are in the domain of 149 – 157 W. The proposed scheme was found to be very effective at determining the influence of input factors on the modules, which is difficult to determine through experimental means.


2021 ◽  
Author(s):  
Denice Feria ◽  
Sonia Sharma ◽  
Yu-Ting Chen ◽  
Zhi-Ying Weng ◽  
Kuo-Pin Chiu ◽  
...  

Abstract Understanding the mechanism of the negative differential resistance (NDR) in transition metal dichalcogenides is essential for fundamental science and the development of electronic devices. Here, the NDR of the current-voltage characteristics was observed based on the glutamine-functionalized WS2 quantum dots (QDs). The NDR effect can be adjusted by varying the applied voltage range, air pressure, surrounding gases, and relative humidity. A peak-to-valley current ratio as high as 6.3 has been achieved at room temperature. Carrier trapping induced by water molecules was suggested to be responsible for the mechanism of the NDR in the glutamine-functionalized WS2 QDs. Investigating the NDR of WS2 QDs may promote the development of memory applications and emerging devices.


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