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 TypeDr GradeEmail
Michael G HutchinsHutchins, Michael GResearcherDoctorate 
عمر أبو الخيرAbu-Alkhair, Omar ResearcherMaster 
M M El-NahassEl-Nahass, M MResearcherDoctorateprof_nahhas@yahoo.com
K A Abdel-HadyAbdel-Hady, K AResearcherDoctorate 

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