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Document Details
Document Type
:
Article In Journal
Document Title
:
Electrical conduction mechanisms in thermally evaporated tungsten trioxide (WO3) thin films
Electrical conduction mechanisms in thermally evaporated tungsten trioxide (WO3) thin films
Subject
:
Physics
Document Language
:
English
Abstract
:
Thin films of amorphous tungsten trioxide, a-WO3, have been thermally evaporated onto glass substrate held at 350K. Annealing at 723K caused the formation of polycrystalline tungsten trioxide, c-WO3, with a monoclinic structure. The dark DC electrical conductivity of both a-WO 3 and c-WO3 was studied over a temperature range from 298 to 625K in two environmental conditions (air and vacuum). A simple Arrhenius law, a polaron model and a variable range hopping model have been used to explain the conduction mechanism for a-WO3 films. Using the variable range hopping model, the density of localized states at the Fermi level, N(EF), was found to be 1.08 × 1019eV -1cm-3. The mechanism of electrical conduction in c-WO3 films is explained by means of the Seto model. The Seto model parameters were determined as the energy barrier (Eb ≤ 0.15eV), the energy of trapping states with respect to the Fermi level (Et ≤ 0.9eV) and the impurity concentration (ND ≤ 4.05 × 1015eV-1cm-3). The thickness dependence of resistivity of c-WO3 films has been found to decrease markedly with increasing film thickness, which is explained on the basis of the effective mean free path model. Using this model, the mean free path of electrons in c-WO 3 films was evaluated. The temperature dependence of the thermoelectric power for a-WO3 films reveals that our samples are n-type semiconductors.
ISSN
:
0953-8984
Journal Name
:
Journal of Physics Condensed Matter
Volume
:
18
Issue Number
:
44
Publishing Year
:
1427 AH
2006 AD
Article Type
:
Article
Added Date
:
Wednesday, December 28, 2011
Researchers
Researcher Name (Arabic)
Researcher Name (English)
Researcher Type
Dr Grade
Email
Michael G Hutchins
Hutchins, Michael G
Researcher
Doctorate
عمر أبو الخير
Abu-Alkhair, Omar
Researcher
Master
M M El-Nahass
El-Nahass, M M
Researcher
Doctorate
prof_nahhas@yahoo.com
K A Abdel-Hady
Abdel-Hady, K A
Researcher
Doctorate
Files
File Name
Type
Description
31840.pdf
pdf
Abstract
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