Electrochromic properties of rf-sputtered tungstic oxide film prepared from a W metal target

Abstract
Tungstic oxide film is prepared from a W metal target by the rf sputtering method and its electrochromic characteristics are compared with that from WO3 target. Maximum coloration efficiency found for both kinds of films are equal and about 0.06 cm2 /mC at the wavelength of 600 nm, which is higher than that of typical evaporated films. Films from the W metal target, for the maximum coloration efficiency, can be prepared at a broader oxygen range of sputtering atmosphere than that of a WO3 target. It is found that films from a W metal target can be prepared at higher input power than that of a WO3 target. Therefore, the W metal target is suitable to get films with required thickness and EC characteristics.