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Influence of hydrogen annealing on the optoelectronic properties of WO3 thin films
Ist Teil von
International journal of hydrogen energy, 2015-09, Vol.40 (36), p.12343-12351
Ort / Verlag
Elsevier Ltd
Erscheinungsjahr
2015
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
The optoelectronic properties of WO3 thin films were investigated after hydrogen treatment. Thin films were deposited on heated substrates by the thermal evaporation and were subsequently annealed at various temperatures in hydrogen for 2 h. Structural studies were performed using X-ray diffraction and atomic force microscopy. As-deposited films were amorphous and became crystalline by thermal annealing. The chemical properties were characterized by X-ray photoelectron spectroscopy, and revealed reduction in stoichiometry and the presence of oxygen vacancies in the films as a result of hydrogen annealing. Spectrophotometric measurements showed that the transmittance of the films was decreased consistently with hydrogen annealing. Significant changes in the optical constants and indirect band gap were noticed. Hall measurements showed the significantly reduced electrical resistivity due to the presence of oxygen vacancies.
•The effect of hydrogen annealing on thermally evaporated WO3 thin films was studied.•Hydrogen was found to be more reactive with WO3 at a higher annealing temperature of 550 °C.•Oxygen defects were created due to the annealing in hydrogen ambient.•Optical properties of the films were modified as a result of annealing.•Electrical properties of the films were significantly enhanced after annealing in hydrogen.