Total absorption of WO3/WS2 stacked thin films in middle infrared light

Abstract

Abstract WS2 and WO3 suffer from low absorption in middle infrared light region, inducing low responsivity of TMDs based infrared optoelectronic detectors working in corresponding wavelength region. In this study we prepared WS2/WO3 stacked thin films by post annealing of evaporated WO3 films in sulphur atmosphere. The obtained stacked thin film samples exhibit resistivity as 55\u202fΩ•cm, which is at least two orders of magnitude lower than that of WS2 and WO3 thin films. These thin film samples present high optical absorption up to 99% from visible to middle infrared light region up to 5\u202fμm, which is much broader than WO3 and WS2 thin films. Such enhanced middle infrared light absorption would benefit the preparation of TMD based middle infrared optoelectronic devices with high performance.