Growth and Characterization of Vacuum Evaporated WO3 Thin Films for Electrochromic Device Application

摘要

WO3 thin films were prepared by vacuum evaporation technique. The deposition parameters such as substrate temperature, deposition rate, film -substrate combination, vacuum during the film deposition were controlled. The influence of substrate temperature on the composition and structure of WO films has been studied. The density of the films was found to be dependent on the substrate temperature and increased from 5.0 to 6.5 g/cm (accuracy - 0.1 g/cm) with increasing temperature from 303 to 553 K and then slightly decreased with further increase of temperature. The films formed at Ts ~ 503 K and heat treated in air at 673 K for six hours showed 20.59 wt% of oxygen indicating that the films attained highest oxidations state (W+6) which is comparable with the starting material. The WO films deposited at Ts ~ 503 K and subsequently annealed at 673 K for 6 hours in air showed characteristic (020), (021), (002) orientationsrepresenting the orthorhombic phase of WO3.