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Title: Investigation into the optoelectrical properties of tungsten oxide thin films annealed in an oxygen air

Tungsten oxide (WO{sub x}) thin film have been deposited onto glass substrates using the thermal vacuum evaporation technique, monitored by an annealing process in a variable oxygen atmosphere. Analysis by X-ray diffraction and Raman spectroscopy showed the structural changes from orthorhombic to monoclinic which depend on the annealing temperature and the oxygen content. AFM study shows that the increase of oxygen content leads to a decrease of the root-mean-square from 94.64 nm to 2 nm. Ellipsometric measurements have been used to evaluate the optical constants. Further, it is found that when the oxygen content increases, the band gap of the annealed layer varies from 3.01 eV to 3.52 eV by against, the Urbach energy decreases. The AC conductivity plot showed a universal power law according to the Jonscher model. Moreover, at high frequency semiconductor-to-metallic behavior has been observed. Finally, the effect of annealing in oxygen atmosphere on their structural modifications, morphological, optical properties and electrical conductivity are reported.
Authors:
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Publication Date:
OSTI Identifier:
22420713
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 60; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; ATOMIC FORCE MICROSCOPY; ELECTRIC CONDUCTIVITY; EV RANGE; IMPEDANCE; LAYERS; MICROSTRUCTURE; MONOCLINIC LATTICES; OPTICAL PROPERTIES; ORTHORHOMBIC LATTICES; OXYGEN; RAMAN SPECTROSCOPY; SEMICONDUCTOR MATERIALS; SUBSTRATES; THIN FILMS; TUNGSTEN OXIDES; VACUUM EVAPORATION; X-RAY DIFFRACTION