Study of Optical and Electrical Properties of In 2 S 3 :Sn Films Deposited by Spray Pyrolysis M. KRAINI, 1,5 N. BOUGUILA, 1 I. HALIDOU, 2 A. MOADHEN, 3 C. VA ´ ZQUEZ-VA ´ ZQUEZ, 4 M.A. LO ´ PEZ-QUINTELA, 4 and S. ALAYA 1 1.—Laboratoire de Physique des Mate ´riaux et des Nanomate ´riaux Applique ´e a ` l’Environnement, Faculte ´ des Sciences de Gabe `s, Universite ´ de Gabe `s, Cite ´ Erriadh Manara Zrig, 6072 Gabe `s, Tunisia. 2.—Unite ´ de Recherches sur les He ´te ´ro-Epitaxies et Applications (URHEA), Faculte ´ des Sciences, 5000 Monastir, Tunisia. 3.—Unite ´ de Recherche Nanomate ´riaux et Photonique, Faculte ´ des Sciences de Tunis, Universite ´ de Tunis El Manar, 2092 El Manar, Tunisia. 4.—Laboratory of Magnetism and Nanotechnology, Institute of Technological Research, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain. 5.—e-mail: mabrouk.1985@hotmail.fr Tin-doped In 2 S 3 films were grown by the chemical spray pyrolysis method using compressed air as a carrier gas. Tin is incorporated in the solution using SnCl 4 . Structural and optical properties of films were investigated by x-ray diffraction (XRD), absorption, Raman and photoluminescence spectroscopies. Field emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectroscopy were used to explore the surface morphology. The proper- ties of In 2 S 3 thin films are influenced by Sn doping. XRD studies revealed that the deposited films were polycrystalline in nature exhibiting cubic structure and oriented preferentially towards (111). According to FESEM, the surface morphology of the films was free of defects. Raman studies showed different peaks related to In 2 S 3 phase and did not show any secondary phases of In-Sn and Sn-S. In 2 S 3 :Sn films exhibited transparency over 60–85% in the visible and infrared regions. The optical band gap was found to vary in the range 2.71–2.58 eV for direct transitions. The room temperature photoluminescence (PL) studies revealed two PL bands, centered at 529 nm (band A) and 725 nm (band B). From these results, one can conclude that our material can be used as transmittive windows in low-cost solar cells. The conductance and capacitance characterization at ambient temperature were also investigated and gave interesting physical properties for photovoltaic applications. Key words: Sn-doped In 2 S 3 , Raman spectroscopy, photoluminescence spectroscopy, admittance spectroscopy INTRODUCTION Metal chalcogenides (sulfides, tellurides and selenides) are of great importance because they are potential candidates for optoelectronic applications such as photodetectors, solar cells, thin film tran- sistors etc. 1–4 Among these materials, In 2 S 3 thin films appear to be promising candidates for many technological applications due to their stability and photoconductive behavior. 5 They can be used as an effective nontoxic substitute for cadmium sulfide (CdS) in thin film chalcogenide-based solar cells. Even though CdS is capable of forming efficient heterojunctions, 6 there is great interest in replacing CdS by a cadmium-free buffer for environmental reasons. It has been reported that an In 2 S 3 buffer layer is quite efficient in yielding good results for ITO/CuInS 2 /In 2 S 3 /Ag thin film solar cells. 7 Cu (In,Ga)Se 2 -based solar cells with In 2 S 3 buffer layer deposited by atomic layer chemical vapor deposition (ALCVD) can reach efficiencies (16.4%) close to those obtained by devices made with a standard CdS buffer layer. 8 An efficiency of 8.9% can be (Received December 23, 2014; accepted April 21, 2015) Journal of ELECTRONIC MATERIALS DOI: 10.1007/s11664-015-3806-5 Ó 2015 The Minerals, Metals & Materials Society