Eur. Phys. J. Appl. Phys. 30, 153-158 (2005)
https://doi.org/10.1051/epjap:2005031

Effect of annealing on properties of CuInS₂ thin films

¹ Laboratoire de Photovoltaïque et Matériaux Semiconducteurs (LPMS), École Nationale d'Ingénieurs de Tunis, BP 37, le Belvédère, 1002 Tunis, Tunisia
² Institut de Physique et Chimie des Matériaux, Strasbourg, France

Corresponding author: Brini_rawdha@yahoo.fr

Received: 12 October 2004
Revised: 22 December 2004
Accepted: 20 January 2005
Published online: 14 April 2005

Abstract

Surface morphology, structural and optical properties of CuInS₂ thin films grown by the single source thermal evaporation in vacuum have been studied. The films were annealed from 250 to 550 °C in argon atmosphere with low oxygen concentration (O₂ < 2 ppm). CuInS₂ films are characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and optical transmittance and reflectance spectra. The maximum grain size of the sample after annealing at 550 °C was over 150 nm. The electron dispersion spectroscopy and X-ray analysis concludes that the polycrystalline CuInS₂ thin film after annealing above 200 °C were sulphur-poor. We obtain CuInS₂ layers with high structural and optical quality at annealing temperature above 450 °C with formation of In₂O₃ as minority phase. The band gap energy of the CuInS₂ films after annealing above 450 °C was about 1.50 eV which perfectly matches the solar spectrum for energy conversion.