Structural and optical studies of chemically deposited Sn 2 S 3 thin films Emine Gu ¨ neri a, *, Fatma Go ¨ de b , Behiye Boyarbay c , Cebrail Gu ¨ mu ¨s ¸ d a Primary Education Department, Erciyes University, 38039 Kayseri, Turkey b Physics Department, Mehmet Akif Ersoy University, 15030 Burdur, Turkey c Physics Department, Erciyes University, 38039 Kayseri, Turkey d Physics Department, Cukurova University, 01330 Adana, Turkey 1. Introduction The interest in semiconductor thin films of chalcogenides such as Cu x S [1], Sn x S y [2], CuInSe 2 [3], CuInS [4] is increasing day by day due to their potential applications. Among these, Sn x S y is very promising as a material for the researchers, due to its different phases and properties [5]. Most of the studies working on Sn x S y thin films have fabricated SnS, SnS 2 thin films by using different deposition methods [6–12]. Nevertheless, it should be noted that until now, little research has been undertaken on the deposition of Sn 2 S 3 thin films. Chen et al. [13] were successful in growing Sn 2 S 3 thin films using a potentiostatic electrodeposition method. Salah et al. [14] and Lopez et al. [15] fabricated these films using a spray pyrolysis technique. However, none of the above studies investi- gated the effect of deposition time on the structural and optical properties of Sn 2 S 3 thin films. Therefore, in this study, we examined the effect of deposition time on these properties of the Sn 2 S 3 thin films deposited using chemical bath deposition (CBD), which is a simple, controllable, and inexpensive technique [16]. Also, the real and imaginary parts of the dielectric constant of the thin films deposited with CBD were calculated for the first time. 2. Experimental details In this study, Sn 2 S 3 thin films were deposited on amorphous glass substrates using CBD method. The substrate, with dimen- sions of 75 mm  25 mm  1 mm, was cleaned with detergent, soaked in diluted acid, rinsed in deionized water, followed by a dip in isopropyl alcohol for 3 min, and then rinsed in deionized water. The cleaned substrates were dried in air prior to deposition. The aqueous solution used for the deposition bath was prepared in a 100 ml beaker by the sequential addition of 5 ml of 1 M stannous chloride (SnCl 2 2H 2 O), 10 ml of 3.75 M triethanolamine (N(CH 2 CH 2 OH) 3 ), 5 ml of 1 M thioacetamide (CH 3 CSNH 2 ) and 80 ml distilled water, while being stirred continuously. The pH of the deposition bath was adjusted to a pH of about 10.7 by adding 5 ml ammonia/ammonium chloride (NH 3 /NH 4 Cl). The dried substrates were immersed vertically in the beaker with the reaction solution remaining unstirred and the temperature was set to 30 8C by using a drying oven. After the deposition times of 20 h, 22 h and 24 h, the thin films obtained were removed from the chemical bath, rinsed with deionized water, dried in air at room temperature and preserved in an airtight plastic container. Next, the thin film deposited on one side of the substrate was cleaned using cotton swabs moistened in dilute hydrochloric acid (HCI) to examine the effect of deposition time. Materials Research Bulletin 47 (2012) 3738–3742 A R T I C L E I N F O Article history: Received 27 December 2011 Received in revised form 20 April 2012 Accepted 11 June 2012 Available online 19 June 2012 PACS: 68.55.a 61.72.up 61.66.Fn 78.30.j 07.79.Cz Keywords: A. Thin film A. Chalcogenides A B S T R A C T Sn 2 S 3 thin films were grown on commercial glass substrates by chemical bath deposition at room temperature. The structural and optical properties of Sn 2 S 3 thin films were studied as a function of deposition time. The thin films were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and UV–vis spectroscopy. The XRD pattern showed that the Sn 2 S 3 thin films had an orthorhombic polycrystalline structure. The lattice constants of the thin films were a = 8.741 A ˚ , b = 14.034 A ˚ and c = 3.728 A ˚ . The characteristic bonds of Sn 2 S 3 were observed at 66.3, 111.7, 224.7 and 308.9 cm 1 using Raman shift experiment. The optical energy band gap of the thin films decreased from 2.12 eV to 2.03 eV with increasing deposition time from 20 to 24 h. The optical constants of the thin films were obtained using the experimentally recorded transmission data as a function of the wavelength. ß 2012 Elsevier Ltd. All rights reserved. * Corresponding author. Tel.: +90 352 437 32 06x37094; fax: +90 248 213 30 99. E-mail address: emineg7@gmail.com (E. Gu ¨ neri). Contents lists available at SciVerse ScienceDirect Materials Research Bulletin jo u rn al h om ep age: ww w.els evier.c o m/lo c ate/mat res b u 0025-5408/$ – see front matter ß 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.materresbull.2012.06.031