scholarly journals Charge Transport Mechanism in Thin Cuticles Holding Nandi Flame Seeds

2009 ◽  
Vol 2009 ◽  
pp. 1-9
Author(s):  
Wycliffe K. Kipnusu ◽  
Gabriel Katana ◽  
Charles M. Migwi ◽  
I. V. S. Rathore ◽  
Joshua R. Sangoro
Keyword(s):  
Transport Mechanism ◽  
Localized States ◽  
Variable Range Hopping ◽  
Charge Transport Mechanism ◽  
Conductivity Measurements ◽  
Ohmic Conduction ◽  
Metal Sample ◽  
Temperature Dependent ◽  
Density Of Localized States ◽  
High Fields

Metal-sample-metal sandwich configuration has been used to investigate DC conductivity in 4 m thick Nandi flame [Spathodea campanulata P. Beauv.] seed cuticles. characteristics showed ohmic conduction at low fields and space charge limited current at high fields. Charge mobility in ohmic region was . Temperature-dependent conductivity measurements have been carried out in the temperature range 320 K 450 K. Activation energy within a temperature of 320 K–440 K was about 0.86 eV. Variable range hopping (VRH) is the main current transport mechanism at the range of 330–440 K. The VRH mechanism was analyzed based on Mott theory and the Mott parameters: density of localized states near the Fermi-level and hopping distance  cm, while the hopping energy () was in the range of 0.72 eV–0.98 eV.

Physical Insights on Charge Transport Mechanism and the LF Noise Behavior in Oxidized Si Structures with Ge Nanoclusters

2016 ◽  
Vol 39 ◽  
pp. 105-113
Author(s):  
Vladimir Lysenko ◽  
Yurii V. Gomeniuk ◽  
Valeriya N. Kudina ◽  
Nikolay Garbar ◽  
Sergey Kondratenko ◽  
...  
Keyword(s):  
Charge Transport ◽  
Transport Mechanism ◽  
Physical Mechanism ◽  
Low Frequency ◽  
Localized States ◽  
Frequency Noise ◽  
Strong Temperature Dependence ◽  
Charge Transport Mechanism ◽  
Dc And Ac Conductivity ◽  
Charge Hopping

To ascertain physical mechanism of charge transport in Si/SiOx structures with Ge nanoclusters the measurements of their DC and AC conductivity, and also the low-frequency measurements were performed. It was revealed that in the temperatures range 110 – 250 K the characteristics measured are governed by the hopping mechanism of charge transport. The model proposed suggests that the charge hopping becomes possible due to the band of localized states inducing in the bandgap of silicon substrate when Ge nanoclusters are introduced. The model was used to estimate some parameters of hopping transport. Also, the analysis of the low-frequency noise measured for Si/SiOx structures with Ge nanoclusters allowed to ascertain the mechanism of charge hopping resulting in strong temperature dependence of the 1/f noise measured.

THE MAGNETORESISTANCE OF CARBON-BLACK SAMPLES AT DIFFERENT TEMPERATURES

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2960-2963 ◽  
Author(s):  
A. APARECIDO-FERREIRA ◽  
E. S. ALVES ◽  
G. M. RIBEIRO ◽  
J. F. SAMPAIO
Keyword(s):  
Magnetic Fields ◽  
Carbon Black ◽  
Temperature Dependence ◽  
Electrical Conduction ◽  
Experimental Results ◽  
Localized States ◽  
Variable Range Hopping ◽  
Coulomb Gap ◽  
Different Temperatures ◽  
High Fields

We present experimental results for the magnetoresistance of carbon-black, in magnetic fields (B) up to 15 T, and its temperature dependence at temperatures (T) from 10 K to 1.2 K. At these temperatures the electrical conduction is given by variable range hopping with Coulomb gap. The results show a B2 dependence at low fields and a B1/2 dependence in the limits of high fields. We show that the model of hydrogenlike localized states cannot explain the experimental results.

LEAKAGE CURRENT CONDUCTION BEHAVIOR OF FLUORINATED POLYIMIDE FILM

2006 ◽  
Vol 20 (06) ◽  
pp. 315-320
Author(s):  
YONG K. LEE
Keyword(s):  
Electric Field ◽  
Leakage Current ◽  
Transport Mechanism ◽  
Conduction Mechanism ◽  
Polyimide Film ◽  
Charge Transport Mechanism ◽  
Ohmic Conduction ◽  
Fluorinated Polyimide ◽  
Current Conduction ◽  
Conduction Behavior

Leakage current of fluorinated polyimide film was measured as function of time, electric field and sample temperature. Several existing conduction and charge transport mechanism was fit to the experimental results. It was concluded that the bulk limited Pool–Frenkel conduction mechanism was likely to dominate for the leakage current at high electric field (higher than 1 MV/cm) and Ohmic conduction was main conduction mechanism at low electric field (lower than 1 MV/cm).

Electronic transport mechanism in polydiacetylene crystals — variable range hopping or phonon-assisted tunnelling

Open Physics ◽  
2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Povilas Pipinys ◽  
Antanas Kiveris
Keyword(s):  
Electronic Transport ◽  
Transport Mechanism ◽  
Rate Dependence ◽  
Experimental Results ◽  
Variable Range Hopping ◽  
Temperature Dependent ◽  
Variable Range ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
High And Low Temperatures

AbstractExperimental results on the current-voltage characteristics of polydiacetylene (PDA) single crystals reported by Aleshin et al [Phys. Rev. Vol. B 69, (2004) art. 214203] are reinterpreted in terms of the phonon-assisted electron tunnelling model. It is shown that the experimental results, measured in the temperature range from 1.8 K to 300 K are consistent with the tunnelling rate dependence on field strength, computed for the same range of temperatures. An advantage of this model over that of Aleshin et al, using the variable range hopping (VRH) model, is the possibility of describing the behaviour of I — V data measured at both high and low temperatures with the same set of parameters characterizing this material. This assertion is confirmed by comparison of the temperature-dependent current-voltage data extracted from Aleshin et al’s work with tunnelling rate dependence on temperature, computed using two different expressions of the phonon-assisted tunnelling theory. The temperature dependence of the conductivity of an ion implanted PDA crystals [B. S. Elman et al, Appl. Phys. Lett., Vol. 46, (1985) p. 100] and polypyrrole [P. Dutta et al, Synth. Met., Vol. 139 (2003) p. 201] are also explained on the basis of this model.

Hopping Conduction in Structures with Ge Nanoclusters Grown on Oxidized Si (001)

2016 ◽  
Vol 39 ◽  
pp. 178-188
Author(s):  
Vladimir Lysenko ◽  
Y.V. Gomeniuk ◽  
Valeriya N. Kudina ◽  
Nikolay Garbar ◽  
Sergey Kondratenko ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Fermi Level ◽  
Transport Mechanism ◽  
Surface Conductivity ◽  
Localized States ◽  
Band Width ◽  
Planar Geometry ◽  
Hopping Conduction ◽  
Variable Range Hopping ◽  
Variable Range

Conductivity and capacitance in structures with Ge nanoclusters grown on oxidized Si (001) with different morphology have been investigated for the temperature range 120-290 K and frequencies 1 kHz-1MHz in co-planar geometry. It was found that structures exhibited T-1/3 conductivity dependence. The Mott’s variable range hopping through quasi-band of localized states at the Fermi level of Ge nanoclusters and their interfaces was found to be the dominant transport mechanism in the surface conductivity channel. The quasi-band width depends of surface morphology varying in the range 110-130 meV, while the middle of the band is located at Ev+140 meV. The peak of reduced conductivity and capacitance were observed under conditions when Fermi level is in the middle of this band.

Variable-range hopping conductivity and structure of density of localized states in LaMnO3+δunder pressure

2006 ◽  
Vol 18 (45) ◽  
pp. 10291-10302 ◽  
Author(s):  
R Laiho ◽  
K G Lisunov ◽  
E Lähderanta ◽  
M L Shubnikov ◽  
Yu P Stepanov ◽  
...  
Keyword(s):  
Localized States ◽  
Variable Range Hopping ◽  
Hopping Conductivity ◽  
Variable Range ◽  
Density Of Localized States

scholarly journals Nonlinear Thermopower Behaviour of N-Type Carbon Nanofibres and Their Melt Mixed Polypropylene Composites

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 269
Author(s):  
Antonio J. Paleo ◽  
Beate Krause ◽  
Maria F. Cerqueira ◽  
Enrique Muñoz ◽  
Petra Pötschke ◽  
...  
Keyword(s):  
Localized States ◽  
Multiwall Carbon Nanotube ◽  
Variable Range Hopping ◽  
Fermi Energy Level ◽  
Temperature Dependent ◽  
Carbon Nanofibres ◽  
Polypropylene Composites ◽  
Carbon Nanofibre ◽  
Temperature Dependent Electrical Conductivity ◽  
Multiwall Carbon

The temperature dependent electrical conductivity σ (T) and thermopower (Seebeck coefficient) S (T) from 303.15 K (30 °C) to 373.15 K (100 °C) of an as-received commercial n-type vapour grown carbon nanofibre (CNF) powder and its melt-mixed polypropylene (PP) composite with 5 wt.% of CNFs have been analysed. At 30 °C, the σ and S of the CNF powder are ~136 S m−1 and −5.1 μV K−1, respectively, whereas its PP/CNF composite showed lower conductivities and less negative S-values of ~15 S m−1 and −3.4 μV K−1, respectively. The σ (T) of both samples presents a dσ/dT < 0 character described by the 3D variable range hopping (VRH) model. In contrast, their S (T) shows a dS/dT > 0 character, also observed in some doped multiwall carbon nanotube (MWCNT) mats with nonlinear thermopower behaviour, and explained here from the contribution of impurities in the CNF structure such as oxygen and sulphur, which cause sharply varying and localized states at approximately 0.09 eV above their Fermi energy level (EF).

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