scholarly journals Electrical Transport Properties ofNi95Ti5Catalyzed Multi wall Carbon Nanotubes Film

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Zishan Husain Khan ◽  
Numan Salah ◽  
Sami Habib
Keyword(s):  
Carbon Nanotubes ◽  
Temperature Region ◽  
Electrical Transport ◽  
Conduction Mechanism ◽  
Variable Range Hopping ◽  
Electrical Transport Properties ◽  
Multi Wall Carbon Nanotubes ◽  
Variable Range ◽  
Temperature Range ◽  
Dimensional Variable

Carbon nanotubes (CNTs) can be understood as one or more graphite sheets rolled up into a seamless cylinder. CNTs have gained much attention and scientific interest due to their unique properties and potential applications since their discovery in 1991. In the present work, we have deposited Ni95Ti5 film using thermal deposition method. Finally, theNi95Ti5catalyzed multi wall carbon nanotubes (MWNTs) are grown on silicon substrate using low pressure chemical vapor deposition (LPCVD) method and the electrical transport properties of this MWNTs film are studied over a temperature range (284–4K) to explain the conduction mechanism. We have suggested two types of conduction mechanism for the entire temperature range. For the temperature region (284–220K), the conduction is due to thermally activated process, whereas the conduction takes place via variable range hopping (VRH) for the temperature range of (220–4K). The VRH mechanism changes from three dimensions to two dimensions as we move down to the temperature below 50K. Therefore, the data for the temperature region (220–50K) is plotted for three dimensional variable range hopping (3D VRH) model and the two dimensional variable range hopping (2D VRH) for lower temperature range of (50–4K). These VRH models give a good fit to the experimental data. Using these models, we have calculated various interesting electrical parameters such as activation energy, density of states, hopping distance and hopping energy.

High Temperature Variable Range Hopping in Heavy Al Implanted 4H-SiC

2016 ◽  
Vol 858 ◽  
pp. 283-286 ◽  
Author(s):  
Antonella Parisini ◽  
Andrea Parisini ◽  
Marco Gorni ◽  
Roberta Nipoti
Keyword(s):  
Electrical Transport ◽  
Room Temperature ◽  
Hole Transport ◽  
Variable Range Hopping ◽  
Electrical Transport Properties ◽  
Hopping Transport ◽  
Variable Range ◽  
Transmission Electron ◽  
Temperature Variable ◽  
Post Implantation

In this work, we confirm and extend the results of a previous study where a variable range hopping transport through localized impurity states has been found to dominate the electrical transport properties of 3×1020 cm-3 and 5×1020 cm-3 Al+ implanted 4H-SiC layers after 1950-2000 °C post implantation annealing. In this study, samples with longer annealing times have been taken into account. The temperature dependence of these sample conductivity follows a variable range hopping law, consistent with a nearly two-dimensional hopping transport of non-interacting carriers that in the highest doped samples, persists up to around room temperature. This result indicates that the hole transport becomes strongly anisotropic on increasing the doping level. At the origin of this unusual electrical behavior, may be the presence of basal plane stacking faults, actually observed by transmission electron microscopy in one of the 5×1020 cm-3 samples

Effect of Morphology on the Electrical Transport Properties of Polyaniline Films for Electronic Applications

1997 ◽  
Vol 488 ◽  
Author(s):  
S. S. Hardaker ◽  
K. Eaiprasertsak ◽  
J. Yon ◽  
R. V. Gregory ◽  
G. X. Tessema
Keyword(s):  
Temperature Dependence ◽  
Electrical Transport ◽  
Chemical Reduction ◽  
Variable Range Hopping ◽  
Structure And Properties ◽  
Electrical Transport Properties ◽  
One Dimensional ◽  
Temperature Dependence Of Conductivity ◽  
Polyaniline Films ◽  
Dimensional Variable

AbstractAlthough it is well known that the oxidation state of polyaniline is an important characteristic, there are few reports of its influence on the development of morphology and electrical properties in fibers and films. In this work, differential scanning calorimentry is used in conjunction with measurements of temperature dependence of conductivity and thermoelectric power to elucidate the intimate relationship between structure and properties. By increasing the amount of chemical reduction of polyaniline solutions, films are prepared which exhibit a thermal transition between 300 and 385 °C, indicative of melting. Increasing the chemical reduction also increases the conductivity of iodine doped films. The most reduced film exhibited a semiconductor transport mechanism, while the other films could be modeled with a quasi-one dimensional variable range hopping mechanism. The temperature dependence of conductivity also showed increasing order for increasing reduction, consistent with the DSC results.

scholarly journals Electrical Properties of Polytypic Mg Doped GaAs Nanowires

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
N. Cifuentes ◽  
E. R. Viana ◽  
H. Limborço ◽  
D. B. Roa ◽  
A. Abelenda ◽  
...  
Keyword(s):  
Electrical Transport ◽  
Field Effect Transistors ◽  
Variable Range Hopping ◽  
Transport Parameters ◽  
Electrical Transport Properties ◽  
Variable Range ◽  
Gaas Nanowires ◽  
P Type ◽  
Mg Doped ◽  
Variable Range Hopping Conduction

The electrical transport properties of individual Mg doped GaAs nanowires are investigated. It is shown that Mg can be successfully used as a nontoxic p-type dopant in GaAs nanowires. The doping levels, expanding over two orders of magnitude, and free holes mobility in the NW were obtained by the analysis of field effect transistors transfer curves. The temperature dependence of the electrical resistivity above room temperature shows that the polytypic structure of the NWs strongly modifies the NWs charge transport parameters, like the resistivity activation energy and holes mobility. At lower temperatures the NWs exhibit variable range hopping conduction. Both Mott and Efros-Shklovskii variable range hopping mechanisms were clearly identified in the nanowires.

scholarly journals Transition of conduction mechanism from band to variable-range hopping conduction due to Al doping in heavily Al-doped 4H-SiC epilayers

2019 ◽  
Vol 58 (9) ◽  
pp. 098004 ◽  
Author(s):  
Hideharu Matsuura ◽  
Akinobu Takeshita ◽  
Tatsuya Imamura ◽  
Kota Takano ◽  
Kazuya Okuda ◽  
...  
Keyword(s):  
Conduction Mechanism ◽  
Hopping Conduction ◽  
Variable Range Hopping ◽  
Al Doping ◽  
Variable Range ◽  
Variable Range Hopping Conduction

scholarly journals Magnetic and Electrical Transport Properties of Vanadium Telluride

1980 ◽  
Vol 35 (7) ◽  
pp. 701-703 ◽  
Author(s):  
C. Prasad ◽  
R. A. Singh
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Magnetic Susceptibility ◽  
Electrical Transport ◽  
Powdered Sample ◽  
Neel Temperature ◽  
Electrical Transport Properties ◽  
Néel Temperature ◽  
Paramagnetic Curie Temperature ◽  
Temperature Range

Measurements of the magnetic susceptibility of a powdered sample of VTe in the temperature range 90 - 700 K, and of the a.c. electrical conductivity (σ), thermoelectric power (θ) and dielectric constant (ε′) of pressed pellets of the compound in the temperature range 300 -1100 K are reported. The compound is found to be antiferromagnetic with Neel temperature 420 ± 5 K. The effective paramagnetic moment and paramagnetic Curie temperature are found to be 1.6 μB and - 250 K, respectively. The dependence of σ, θ and ε′ on temperature shows no anomaly at the Neel temperature and is indicative of the metallic nature of the compound.

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