Structural, optical and electrical properties of β-In2S3-3xO3x thin films obtained by PVD

β-In2S3−3xO3x thin films have been synthesized following a dry physical process on glass substrates. The highest temperature used during the elaboration of the films is 473 K. The films have been structurally and optically characterized by X-ray diffraction, electronic microprobe analysis, X-ray photoelectron spectroscopy, scanning electronic microscopy and atomic force microscopy. They crystallize in the tetragonal β-In2S3 structure. Their optical band gap varies from 2.1 eV, when they are pure β-In2S3, to 2.9 eV when they contain 8.5 at.% of oxygen. The electrical properties of the thin films have also been determined, they have n-type electrical conductivity of approximately 10−3 S·cm−1. All these properties make β-In2S3−3xO3x thin films good candidates to substitute CBD-CdS as buffer layer in CIGS-based solar cells.