beta-In2S3 thin films, deposited by spray pyrolysis, were treated in N-2 and air plasmas at 240 and 400 Pa. X-ray diffraction, SEM, and EDS analysis, and optical and electrical studies have been used to characterize the as-prepared and plasma treated thin films. The post-deposition plasma treatments affect the morphology and the optoelectronic properties of the In2S3 thin films. The In2S3 thin films treated with N-2 plasma at 240 Pa showed an optical band gap, E-g, of 2.16 eV and an electrical conductivity of 2 x 10(-2) (Omega cm)(-1). (C) 2008 Elsevier B.V. All rights reserved.