scholarly journals The Electronic Transport Mechanism in Amorphous Tetrahedrally-Coordinated Carbon Films

1997 ◽  
Vol 498 ◽  
Author(s):  
J. P. Sullivan ◽  
T. A. Friedmann ◽  
R. G. Dunn ◽  
E. B. Stechel ◽  
P. A. Schultz ◽  
...  
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Stress Relaxation ◽  
Electronic Transport ◽  
Transport Mechanism ◽  
Thermal Evolution ◽  
Carbon Films ◽  
Temperature Dependent ◽  
Thermally Activated ◽  
Relaxation Measurements

ABSTRACTThe electronic transport mechanism in tetrahedrally-coordinated amorphous carbon was investigated using measurements of stress relaxation, thermal evolution of electrical conductivity, and temperature-dependent conductivity measurements. Stress relaxation measurements were used to determine the change in 3-fold coordinated carbon concentration, and the electrical conductivity was correlated to this change. It was found that the conductivity was exponentially proportional to the change in 3-fold concentration, indicating a tunneling or hopping transport mechanism. It was also found that the activation energy for transport decreased with increasing anneal temperature. The decrease in activation energy was responsible for the observed increase in electrical conductivity. A model is described wherein the transport in this material is described by thermally activated conduction along 3-fold linkages or chains with variable range and variable orientation hopping. Thermal annealing leads to chain ripening and a reduction in the activation energy for transport.

Structural, Electrical and Optical Properties of Laser Deposited Thin Films of Srco0.8Fe0.2O3-δ

1994 ◽  
Vol 369 ◽  
Author(s):  
C. Zhang ◽  
H. Deng ◽  
J. Varon ◽  
B. Abeles ◽  
Y. Yang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Activation Energy ◽  
Electrical Conductivity ◽  
Optical Properties ◽  
Optical Absorption ◽  
Laser Deposition ◽  
Electrical And Optical Properties ◽  
Thermally Activated ◽  
Characteristic Features

AbstractThin film SrCo0.8Fe0.2O3-δ were made by pulse laser deposition. The electrical conductivity is thermally activated in the temperature 25-500 °C with an activation energy of 0.17-0.19 eV and is temperature independant from 500-800 °C. The optical absorption shows characteristic features which are interpreted qualitatively in terms of a simple band structure diagram.

Relaxation Measurements of the Persistent Photoconductivity in Sulfur-Doped a-Si:H.

1996 ◽  
Vol 420 ◽  
Author(s):  
D. Quicker ◽  
J. Kakalios
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Sulfur Atom ◽  
Hydrogenated Amorphous Silicon ◽  
Persistent Photoconductivity ◽  
Sulfur Concentration ◽  
Illumination Time ◽  
Thermally Activated ◽  
Relaxation Measurements ◽  
Hydrogenated Amorphous

AbstractThe slow relaxation of the persistent photoconductivity (PPC) effect in sulfur-doped hydrogenated amorphous silicon (a-Si:H) has been measured as a function of temperature and illumination time. The relaxation is found to be thermally activated, with an activation energy which varies with sulfur concentration, while illuminating the film for a longer time leads to a longer relaxation time. A correlation is observed between changes of the photoconductivity during illumination and the magnitude of the PPC effect following illumination. These effects are also observed in compensated a-Si:H, suggesting that the mechanism for the PPC effect is the same in both sulfur-doped a-Si:H and compensated a-Si:H. The presence of donor and compensating acceptor states in sulfur-doped a-Si:H could arise from valence alternation pair sulfur atom defects.

scholarly journals The electronic transport mechanism in amorphous tetrahedrally-coordinated carbon films

1998 ◽  
Author(s):  
J.P. Sullivan ◽  
T.A. Friedmann ◽  
R.G. Dunn ◽  
E.B. Stechel ◽  
P.A. Schultz
Keyword(s):  
Electronic Transport ◽  
Transport Mechanism ◽  
Carbon Films

Stress-Time-Temperature Relations in Polysulfide Rubbers

1946 ◽  
Vol 19 (4) ◽  
pp. 1178-1192 ◽  
Author(s):  
M. D. Stern ◽  
A. V. Tobolsky
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
High Temperature ◽  
Stress Relaxation ◽  
Relaxation Process ◽  
Network Structure ◽  
Constant Load ◽  
Internal Structures ◽  
Relaxation Measurements ◽  
Temperature Relaxation

Abstract Polysulfide rubbers of various internal structures have been investigated by measurements of continuous and intermittent relaxation of stress and by creep under constant load at temperatures between 35° C and 120° C. Continuous stress relaxation measurements indicate that these rubbers obey approximately the simple Maxwellian law of relaxation of stress, which indicates that one definite type of bond in the network structure is responsible for stress decay. The activation energy for the relaxation process in each of the polysulfide rubbers is nearly the same, indicating that the same type of bond is responsible for the relaxation behavior of all the polysulfides investigated. In contrast to hydrocarbon rubbers, oxygen is not the cause of high temperature relaxation in polysulfide rubbers, nor does heating in air at moderate temperatures for times comparable to the relaxation time produce changes in physical properties as determined by modulus or by appearance of the samples. Several possibilities regarding the mechanism of the relaxation process and the type of bond involved are considered in the light of the experimental results.

Electrical Conductivity of Pyrolysed Polyamides Derived from 1,4-Bis(2-Cyano-2-Carboxyvinyl)Benzene and Various Aromatic Diamines

1997 ◽  
Vol 9 (2) ◽  
pp. 189-203 ◽  
Author(s):  
Christoforos A Krontiras ◽  
Michael N Pisanias ◽  
John A Mikroyannidis ◽  
Stavroula N Georga
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Pyrolysis Temperature ◽  
Degree Of Crystallinity ◽  
Chain Mechanism ◽  
Aromatic Diamines ◽  
X Ray ◽  
Thermally Activated ◽  
Heat Treated

The electrical conductivity of three homopolyamides, synthesized from aromatic diamines and identified as PAM, PAP and PAS, was investigated as a function of temperature in the range 100–700 K, following pyrolysis for 24 h in an atmosphere of N2 at temperatures of 550, 700, 800 and 850 °C. X-ray profiles were recorded for the three polymers before and following pyrolysis. The non-heat-treated polymers are amorphous whereas a certain degree of crystallinity is observed following pyrolysis. The observed conductivity covered a range from 10−9 to 10 S cm−1 depending on the polymer and the pyrolysis temperature. The results suggest that the conductivity is thermally activated and is due to two mechanisms, the intra-chain conductivity and the inter-chain conductivity. The activation energy for the intra-chain mechanism varies from 0.36 to 0.01 eV and for the inter-chain mechanism the activation energy varies from 2.76 to 0.08 eV, depending on the pyrolysis temperature for both mechanisms.

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.

Effect of Cu doping on the electrical Properties of ZnTe by Vacuum Thermal Evaporation

2018 ◽  
Vol 31 (3) ◽  
pp. 20
Author(s):  
Sarmad M. M. Ali ◽  
Alia A.A. Shehab ◽  
Samir A. Maki
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Hall Effect ◽  
Carrier Concentration ◽  
Hall Mobility ◽  
Cu Doping ◽  
Before And After ◽  
Hall Effect Measurements ◽  
Evaporation Technique ◽  
P Type

In this study, the ZnTe thin films were deposited on a glass substrate at a thickness of 400nm using vacuum evaporation technique (2×10-5mbar) at RT. Electrical conductivity and Hall effect measurements have been investigated as a function of variation of the doping ratios (3,5,7%) of the Cu element on the thin ZnTe films. The temperature range of (25-200°C) is to record the electrical conductivity values. The results of the films have two types of transport mechanisms of free carriers with two values of activation energy (Ea1, Ea2), expect 3% Cu. The activation energy (Ea1) increased from 29meV to 157meV before and after doping (Cu at 5%) respectively. The results of Hall effect measurements of ZnTe , ZnTe:Cu films show that all films were (p-type), the carrier concentration (1.1×1020 m-3) , Hall mobility (0.464m2/V.s) for pure ZnTe film, increases the carrier concentration (6.3×1021m-3) Hall mobility (2m2/V.s) for doping (Cu at 3%) film, but  decreases by increasing Cu concentration.

Theoretical investigation of electronic transport mechanism in molecular junction by tunneling

2021 ◽  
Vol 607 ◽  
pp. 412705
Author(s):  
Mayra Moura-Moreira ◽  
Denner F.S. Ferreira ◽  
Jordan Del Nero
Keyword(s):  
Theoretical Investigation ◽  
Electronic Transport ◽  
Transport Mechanism ◽  
Molecular Junction
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